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From ste...@apache.org
Subject [2/3] hadoop git commit: YARN-2768 Improved Yarn Registry service record structure (stevel)
Date Thu, 06 Nov 2014 20:22:38 GMT
YARN-2768 Improved Yarn Registry service record structure (stevel)


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/e333584c
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/e333584c
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/e333584c

Branch: refs/heads/branch-2.6
Commit: e333584ca6e37f0a51cb27dadbe9047f7775d8e7
Parents: b557f68
Author: Steve Loughran <stevel@apache.org>
Authored: Thu Nov 6 20:21:25 2014 +0000
Committer: Steve Loughran <stevel@apache.org>
Committed: Thu Nov 6 20:21:49 2014 +0000

----------------------------------------------------------------------
 hadoop-yarn-project/CHANGES.txt                 |   2 +
 .../apache/hadoop/registry/cli/RegistryCli.java |  25 +-
 .../registry/client/binding/JsonSerDeser.java   | 142 +++++------
 .../client/binding/RegistryTypeUtils.java       | 166 ++++++++-----
 .../registry/client/binding/RegistryUtils.java  |   7 +-
 .../client/exceptions/NoRecordException.java    |  10 +-
 .../impl/zk/RegistryOperationsService.java      |  12 +-
 .../registry/client/types/AddressTypes.java     |   2 +
 .../hadoop/registry/client/types/Endpoint.java  | 131 ++++++++---
 .../registry/client/types/ProtocolTypes.java    |   7 +-
 .../registry/client/types/ServiceRecord.java    |  26 +--
 .../client/types/ServiceRecordHeader.java       |  59 -----
 .../src/main/tla/yarnregistry.tla               |  94 ++++++--
 .../hadoop/registry/RegistryTestHelper.java     |  36 ++-
 .../client/binding/TestMarshalling.java         |  72 ++++--
 .../operations/TestRegistryOperations.java      |   5 +-
 .../src/site/markdown/registry/yarn-registry.md | 233 +++++++++++++++----
 17 files changed, 623 insertions(+), 406 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/CHANGES.txt
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index 5eb58d3..33331b4 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -665,6 +665,8 @@ Release 2.6.0 - UNRELEASED
     YARN-2677 registry punycoding of usernames doesn't fix all usernames to be
     DNS-valid (stevel)
 
+    YARN-2768 Improved Yarn Registry service record structure (stevel)
+
     ---
 
     YARN-2598 GHS should show N/A instead of null for the inaccessible information

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/cli/RegistryCli.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/cli/RegistryCli.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/cli/RegistryCli.java
index 863039e..bf2b5e5 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/cli/RegistryCli.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/cli/RegistryCli.java
@@ -24,6 +24,7 @@ import java.io.PrintStream;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.util.List;
+import java.util.Map;
 
 import com.google.common.base.Preconditions;
 import org.apache.commons.cli.CommandLine;
@@ -174,24 +175,22 @@ public class RegistryCli extends Configured implements Tool {
 				ServiceRecord record = registry.resolve(argsList.get(1));
 
 				for (Endpoint endpoint : record.external) {
-					if ((endpoint.protocolType.equals(ProtocolTypes.PROTOCOL_WEBUI))
-							|| (endpoint.protocolType.equals(ProtocolTypes.PROTOCOL_REST))) {
-						sysout.print(" Endpoint(ProtocolType="
-								+ endpoint.protocolType + ", Api="
-								+ endpoint.api + "); Uris are: ");
-					} else {
-						sysout.print(" Endpoint(ProtocolType="
+						sysout.println(" Endpoint(ProtocolType="
 								+ endpoint.protocolType + ", Api="
 								+ endpoint.api + ");"
 								+ " Addresses(AddressType="
 								+ endpoint.addressType + ") are: ");
 
-					}
-					for (List<String> a : endpoint.addresses) {
-						sysout.print(a + " ");
-					}
-					sysout.println();
-				}
+          for (Map<String, String> address : endpoint.addresses) {
+            sysout.println("  [ ");
+            for (Map.Entry<String, String> entry : address.entrySet()) {
+              sysout.println("    " + entry.getKey()
+                             + ": \"" + entry.getValue() + "\"");
+            }
+            sysout.println("  ]");
+          }
+          sysout.println();
+        }
 				return 0;
       } catch (Exception e) {
         syserr.println(analyzeException("resolve", e, argsList));

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/JsonSerDeser.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/JsonSerDeser.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/JsonSerDeser.java
index e086e36..af4e4f4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/JsonSerDeser.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/JsonSerDeser.java
@@ -19,6 +19,7 @@
 package org.apache.hadoop.registry.client.binding;
 
 import com.google.common.base.Preconditions;
+import org.apache.commons.lang.StringUtils;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.fs.FSDataInputStream;
@@ -45,8 +46,6 @@ import java.io.File;
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.InputStream;
-import java.nio.ByteBuffer;
-import java.util.Arrays;
 
 /**
  * Support for marshalling objects to and from JSON.
@@ -62,30 +61,30 @@ public class JsonSerDeser<T> {
 
   private static final Logger LOG = LoggerFactory.getLogger(JsonSerDeser.class);
   private static final String UTF_8 = "UTF-8";
-  public static final String E_NO_SERVICE_RECORD = "No service record at path";
+  public static final String E_NO_DATA = "No data at path";
+  public static final String E_DATA_TOO_SHORT = "Data at path too short";
+  public static final String E_MISSING_MARKER_STRING =
+      "Missing marker string: ";
 
   private final Class<T> classType;
   private final ObjectMapper mapper;
-  private final byte[] header;
 
   /**
    * Create an instance bound to a specific type
    * @param classType class to marshall
-   * @param header byte array to use as header
    */
-  public JsonSerDeser(Class<T> classType, byte[] header) {
+  public JsonSerDeser(Class<T> classType) {
     Preconditions.checkArgument(classType != null, "null classType");
-    Preconditions.checkArgument(header != null, "null header");
     this.classType = classType;
     this.mapper = new ObjectMapper();
     mapper.configure(DeserializationConfig.Feature.FAIL_ON_UNKNOWN_PROPERTIES,
         false);
-    // make an immutable copy to keep findbugs happy.
-    byte[] h = new byte[header.length];
-    System.arraycopy(header, 0, h, 0, header.length);
-    this.header = h;
   }
 
+  /**
+   * Get the simple name of the class type to be marshalled
+   * @return the name of the class being marshalled
+   */
   public String getName() {
     return classType.getSimpleName();
   }
@@ -183,7 +182,7 @@ public class JsonSerDeser<T> {
     if (count != len) {
       throw new EOFException(path.toString() + ": read finished prematurely");
     }
-    return fromBytes(path.toString(), b, 0);
+    return fromBytes(path.toString(), b);
   }
 
   /**
@@ -206,8 +205,7 @@ public class JsonSerDeser<T> {
    * @throws IOException on any failure
    */
   private void writeJsonAsBytes(T instance,
-      DataOutputStream dataOutputStream) throws
-      IOException {
+      DataOutputStream dataOutputStream) throws IOException {
     try {
       byte[] b = toBytes(instance);
       dataOutputStream.write(b);
@@ -228,36 +226,50 @@ public class JsonSerDeser<T> {
   }
 
   /**
-   * Convert JSON To bytes, inserting the header
-   * @param instance instance to convert
-   * @return a byte array
-   * @throws IOException
+   * Deserialize from a byte array
+   * @param path path the data came from
+   * @param bytes byte array
+   * @throws IOException all problems
+   * @throws EOFException not enough data
+   * @throws InvalidRecordException if the parsing failed -the record is invalid
    */
-  public byte[] toByteswithHeader(T instance) throws IOException {
-    byte[] body = toBytes(instance);
-
-    ByteBuffer buffer = ByteBuffer.allocate(body.length + header.length);
-    buffer.put(header);
-    buffer.put(body);
-    return buffer.array();
+  public T fromBytes(String path, byte[] bytes) throws IOException,
+      InvalidRecordException {
+    return fromBytes(path, bytes, "");
   }
 
   /**
-   * Deserialize from a byte array
+   * Deserialize from a byte array, optionally checking for a marker string.
+   * <p>
+   * If the marker parameter is supplied (and not empty), then its presence
+   * will be verified before the JSON parsing takes place; it is a fast-fail
+   * check. If not found, an {@link InvalidRecordException} exception will be
+   * raised
    * @param path path the data came from
    * @param bytes byte array
-   * @return offset in the array to read from
+   * @param marker an optional string which, if set, MUST be present in the
+   * UTF-8 parsed payload.
+   * @return The parsed record
    * @throws IOException all problems
    * @throws EOFException not enough data
-   * @throws InvalidRecordException if the parsing failed -the record is invalid
+   * @throws InvalidRecordException if the JSON parsing failed.
+   * @throws NoRecordException if the data is not considered a record: either
+   * it is too short or it did not contain the marker string.
    */
-  public T fromBytes(String path, byte[] bytes, int offset) throws IOException,
-      InvalidRecordException {
-    int data = bytes.length - offset;
-    if (data <= 0) {
-      throw new EOFException("No data at " + path);
+  public T fromBytes(String path, byte[] bytes, String marker)
+      throws IOException, NoRecordException, InvalidRecordException {
+    int len = bytes.length;
+    if (len == 0 ) {
+      throw new NoRecordException(path, E_NO_DATA);
+    }
+    if (StringUtils.isNotEmpty(marker) && len < marker.length()) {
+      throw new NoRecordException(path, E_DATA_TOO_SHORT);
+    }
+    String json = new String(bytes, 0, len, UTF_8);
+    if (StringUtils.isNotEmpty(marker)
+        && !json.contains(marker)) {
+      throw new NoRecordException(path, E_MISSING_MARKER_STRING + marker);
     }
-    String json = new String(bytes, offset, data, UTF_8);
     try {
       return fromJson(json);
     } catch (JsonProcessingException e) {
@@ -266,52 +278,7 @@ public class JsonSerDeser<T> {
   }
 
   /**
-   * Read from a byte array to a type, checking the header first
-   * @param path source of data
-   * @param buffer buffer
-   * @return the parsed structure
-   * Null if the record was too short or the header did not match
-   * @throws IOException on a failure
-   * @throws NoRecordException if header checks implied there was no record
-   * @throws InvalidRecordException if record parsing failed
-   */
-  @SuppressWarnings("unchecked")
-  public T fromBytesWithHeader(String path, byte[] buffer) throws IOException {
-    int hlen = header.length;
-    int blen = buffer.length;
-    if (hlen > 0) {
-      if (blen < hlen) {
-        throw new NoRecordException(path, E_NO_SERVICE_RECORD);
-      }
-      byte[] magic = Arrays.copyOfRange(buffer, 0, hlen);
-      if (!Arrays.equals(header, magic)) {
-        LOG.debug("start of entry does not match service record header at {}",
-            path);
-        throw new NoRecordException(path, E_NO_SERVICE_RECORD);
-      }
-    }
-    return fromBytes(path, buffer, hlen);
-  }
-
-  /**
-   * Check if a buffer has a header which matches this record type
-   * @param buffer buffer
-   * @return true if there is a match
-   * @throws IOException
-   */
-  public boolean headerMatches(byte[] buffer) throws IOException {
-    int hlen = header.length;
-    int blen = buffer.length;
-    boolean matches = false;
-    if (blen > hlen) {
-      byte[] magic = Arrays.copyOfRange(buffer, 0, hlen);
-      matches = Arrays.equals(header, magic);
-    }
-    return matches;
-  }
-
-  /**
-   * Convert an object to a JSON string
+   * Convert an instance to a JSON string
    * @param instance instance to convert
    * @return a JSON string description
    * @throws JsonParseException parse problems
@@ -324,4 +291,19 @@ public class JsonSerDeser<T> {
     return mapper.writeValueAsString(instance);
   }
 
+  /**
+   * Convert an instance to a string form for output. This is a robust
+   * operation which will convert any JSON-generating exceptions into
+   * error text.
+   * @param instance non-null instance
+   * @return a JSON string
+   */
+  public String toString(T instance) {
+    Preconditions.checkArgument(instance != null, "Null instance argument");
+    try {
+      return toJson(instance);
+    } catch (IOException e) {
+      return "Failed to convert to a string: " + e;
+    }
+  }
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryTypeUtils.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryTypeUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryTypeUtils.java
index b4254a3..ec59d59 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryTypeUtils.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryTypeUtils.java
@@ -22,17 +22,19 @@ import com.google.common.base.Preconditions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
-import org.apache.hadoop.registry.client.types.AddressTypes;
+import static org.apache.hadoop.registry.client.types.AddressTypes.*;
 import org.apache.hadoop.registry.client.types.Endpoint;
 import org.apache.hadoop.registry.client.types.ProtocolTypes;
+import org.apache.hadoop.registry.client.types.ServiceRecord;
 
 import java.net.InetSocketAddress;
 import java.net.MalformedURLException;
 import java.net.URI;
 import java.net.URL;
 import java.util.ArrayList;
-import java.util.Arrays;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Static methods to work with registry types —primarily endpoints and the
@@ -94,79 +96,66 @@ public class RegistryTypeUtils {
     Preconditions.checkArgument(protocolType != null, "null protocolType");
     Preconditions.checkArgument(hostname != null, "null hostname");
     return new Endpoint(api,
-        AddressTypes.ADDRESS_HOSTNAME_AND_PORT,
+        ADDRESS_HOSTNAME_AND_PORT,
         protocolType,
-        tuplelist(hostname, Integer.toString(port)));
+        hostnamePortPair(hostname, port));
   }
 
   /**
    * Create an IPC endpoint
    * @param api API
-   * @param protobuf flag to indicate whether or not the IPC uses protocol
-   * buffers
    * @param address the address as a tuple of (hostname, port)
    * @return the new endpoint
    */
-  public static Endpoint ipcEndpoint(String api,
-      boolean protobuf, List<String> address) {
-    ArrayList<List<String>> addressList = new ArrayList<List<String>>();
-    if (address != null) {
-      addressList.add(address);
-    }
+  public static Endpoint ipcEndpoint(String api, InetSocketAddress address) {
     return new Endpoint(api,
-        AddressTypes.ADDRESS_HOSTNAME_AND_PORT,
-        protobuf ? ProtocolTypes.PROTOCOL_HADOOP_IPC_PROTOBUF
-                 : ProtocolTypes.PROTOCOL_HADOOP_IPC,
-        addressList);
+        ADDRESS_HOSTNAME_AND_PORT,
+        ProtocolTypes.PROTOCOL_HADOOP_IPC,
+        address== null ? null: hostnamePortPair(address));
   }
 
   /**
-   * Create a single-element list of tuples from the input.
-   * that is, an input ("a","b","c") is converted into a list
-   * in the form [["a","b","c"]]
-   * @param t1 tuple elements
-   * @return a list containing a single tuple
+   * Create a single entry map
+   * @param key map entry key
+   * @param val map entry value
+   * @return a 1 entry map.
    */
-  public static List<List<String>> tuplelist(String... t1) {
-    List<List<String>> outer = new ArrayList<List<String>>();
-    outer.add(tuple(t1));
-    return outer;
+  public static Map<String, String> map(String key, String val) {
+    Map<String, String> map = new HashMap<String, String>(1);
+    map.put(key, val);
+    return map;
   }
 
   /**
-   * Create a tuples from the input.
-   * that is, an input ("a","b","c") is converted into a list
-   * in the form ["a","b","c"]
-   * @param t1 tuple elements
-   * @return a single tuple as a list
+   * Create a URI
+   * @param uri value
+   * @return a 1 entry map.
    */
-  public static List<String> tuple(String... t1) {
-    return Arrays.asList(t1);
+  public static Map<String, String> uri(String uri) {
+    return map(ADDRESS_URI, uri);
   }
 
   /**
-   * Create a tuples from the input, converting all to Strings in the process
-   * that is, an input ("a", 7, true) is converted into a list
-   * in the form ["a","7,"true"]
-   * @param t1 tuple elements
-   * @return a single tuple as a list
+   * Create a (hostname, port) address pair
+   * @param hostname hostname
+   * @param port port
+   * @return a 1 entry map.
    */
-  public static List<String> tuple(Object... t1) {
-    List<String> l = new ArrayList<String>(t1.length);
-    for (Object t : t1) {
-      l.add(t.toString());
-    }
-    return l;
+  public static Map<String, String> hostnamePortPair(String hostname, int port) {
+    Map<String, String> map =
+        map(ADDRESS_HOSTNAME_FIELD, hostname);
+    map.put(ADDRESS_PORT_FIELD, Integer.toString(port));
+    return map;
   }
 
   /**
-   * Convert a socket address pair into a string tuple, (host, port).
-   * TODO JDK7: move to InetAddress.getHostString() to avoid DNS lookups.
-   * @param address an address
-   * @return an element for the address list
+   * Create a (hostname, port) address pair
+   * @param address socket address whose hostname and port are used for the
+   * generated address.
+   * @return a 1 entry map.
    */
-  public static List<String> marshall(InetSocketAddress address) {
-    return tuple(address.getHostName(), address.getPort());
+  public static Map<String, String> hostnamePortPair(InetSocketAddress address) {
+    return hostnamePortPair(address.getHostName(), address.getPort());
   }
 
   /**
@@ -199,25 +188,37 @@ public class RegistryTypeUtils {
     if (epr == null) {
       return null;
     }
-    requireAddressType(AddressTypes.ADDRESS_URI, epr);
-    List<List<String>> addresses = epr.addresses;
+    requireAddressType(ADDRESS_URI, epr);
+    List<Map<String, String>> addresses = epr.addresses;
     if (addresses.size() < 1) {
       throw new InvalidRecordException(epr.toString(),
           "No addresses in endpoint");
     }
     List<String> results = new ArrayList<String>(addresses.size());
-    for (List<String> address : addresses) {
-      if (address.size() != 1) {
-        throw new InvalidRecordException(epr.toString(),
-            "Address payload invalid: wrong element count: " +
-            address.size());
-      }
-      results.add(address.get(0));
+    for (Map<String, String> address : addresses) {
+      results.add(getAddressField(address, ADDRESS_URI));
     }
     return results;
   }
 
   /**
+   * Get a specific field from an address -raising an exception if
+   * the field is not present
+   * @param address address to query
+   * @param field field to resolve
+   * @return the resolved value. Guaranteed to be non-null.
+   * @throws InvalidRecordException if the field did not resolve
+   */
+  public static String getAddressField(Map<String, String> address,
+      String field) throws InvalidRecordException {
+    String val = address.get(field);
+    if (val == null) {
+      throw new InvalidRecordException("", "Missing address field: " + field);
+    }
+    return val;
+  }
+
+  /**
    * Get the address URLs. Guranteed to return at least one address.
    * @param epr endpoint
    * @return the address as a URL
@@ -237,4 +238,53 @@ public class RegistryTypeUtils {
     }
     return results;
   }
+
+  /**
+   * Validate the record by checking for null fields and other invalid
+   * conditions
+   * @param path path for exceptions
+   * @param record record to validate. May be null
+   * @throws InvalidRecordException on invalid entries
+   */
+  public static void validateServiceRecord(String path, ServiceRecord record)
+      throws InvalidRecordException {
+    if (record == null) {
+      throw new InvalidRecordException(path, "Null record");
+    }
+    if (!ServiceRecord.RECORD_TYPE.equals(record.type)) {
+      throw new InvalidRecordException(path,
+          "invalid record type field: \"" + record.type + "\"");
+    }
+
+    if (record.external != null) {
+      for (Endpoint endpoint : record.external) {
+        validateEndpoint(path, endpoint);
+      }
+    }
+    if (record.internal != null) {
+      for (Endpoint endpoint : record.internal) {
+        validateEndpoint(path, endpoint);
+      }
+    }
+  }
+
+  /**
+   * Validate the endpoint by checking for null fields and other invalid
+   * conditions
+   * @param path path for exceptions
+   * @param endpoint endpoint to validate. May be null
+   * @throws InvalidRecordException on invalid entries
+   */
+  public static void validateEndpoint(String path, Endpoint endpoint)
+      throws InvalidRecordException {
+    if (endpoint == null) {
+      throw new InvalidRecordException(path, "Null endpoint");
+    }
+    try {
+      endpoint.validate();
+    } catch (RuntimeException e) {
+      throw new InvalidRecordException(path, e.toString());
+    }
+  }
+
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryUtils.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryUtils.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryUtils.java
index 8caf400..68dc84e 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryUtils.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/binding/RegistryUtils.java
@@ -33,7 +33,6 @@ import org.apache.hadoop.registry.client.exceptions.NoRecordException;
 import org.apache.hadoop.registry.client.impl.zk.RegistryInternalConstants;
 import org.apache.hadoop.registry.client.types.RegistryPathStatus;
 import org.apache.hadoop.registry.client.types.ServiceRecord;
-import org.apache.hadoop.registry.client.types.ServiceRecordHeader;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -314,7 +313,7 @@ public class RegistryUtils {
       Collection<RegistryPathStatus> stats) throws IOException {
     Map<String, ServiceRecord> results = new HashMap<String, ServiceRecord>(stats.size());
     for (RegistryPathStatus stat : stats) {
-      if (stat.size > ServiceRecordHeader.getLength()) {
+      if (stat.size > ServiceRecord.RECORD_TYPE.length()) {
         // maybe has data
         String path = join(parentpath, stat.path);
         try {
@@ -344,7 +343,6 @@ public class RegistryUtils {
    * <p>
    * @param operations operation support for fetches
    * @param parentpath path of the parent of all the entries
-   * @param stats a map of name:value mappings.
    * @return a possibly empty map of fullpath:record.
    * @throws IOException for any IO Operation that wasn't ignored.
    */
@@ -362,7 +360,6 @@ public class RegistryUtils {
    * <p>
    * @param operations operation support for fetches
    * @param parentpath path of the parent of all the entries
-   * @param stats a map of name:value mappings.
    * @return a possibly empty map of fullpath:record.
    * @throws IOException for any IO Operation that wasn't ignored.
    */
@@ -382,7 +379,7 @@ public class RegistryUtils {
    */
   public static class ServiceRecordMarshal extends JsonSerDeser<ServiceRecord> {
     public ServiceRecordMarshal() {
-      super(ServiceRecord.class, ServiceRecordHeader.getData());
+      super(ServiceRecord.class);
     }
   }
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/exceptions/NoRecordException.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/exceptions/NoRecordException.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/exceptions/NoRecordException.java
index 160433f..b81b9d4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/exceptions/NoRecordException.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/exceptions/NoRecordException.java
@@ -21,17 +21,11 @@ package org.apache.hadoop.registry.client.exceptions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.registry.client.types.ServiceRecord;
-import org.apache.hadoop.registry.client.types.ServiceRecordHeader;
 
 /**
  * Raised if there is no {@link ServiceRecord} resolved at the end
- * of the specified path, for reasons such as:
- * <ul>
- *   <li>There wasn't enough data to contain a Service Record.</li>
- *   <li>The start of the data did not match the {@link ServiceRecordHeader}
- *   header.</li>
- * </ul>
- *
+ * of the specified path.
+ * <p>
  * There may be valid data of some form at the end of the path, but it does
  * not appear to be a Service Record.
  */

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistryOperationsService.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistryOperationsService.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistryOperationsService.java
index 7c01bdf..271ab25 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistryOperationsService.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/impl/zk/RegistryOperationsService.java
@@ -24,9 +24,11 @@ import org.apache.hadoop.classification.InterfaceStability;
 import org.apache.hadoop.registry.client.api.BindFlags;
 import org.apache.hadoop.registry.client.api.RegistryOperations;
 
+import org.apache.hadoop.registry.client.binding.RegistryTypeUtils;
 import org.apache.hadoop.registry.client.binding.RegistryUtils;
 import org.apache.hadoop.registry.client.binding.RegistryPathUtils;
 import org.apache.hadoop.registry.client.exceptions.InvalidPathnameException;
+import org.apache.hadoop.registry.client.exceptions.NoRecordException;
 import org.apache.hadoop.registry.client.types.RegistryPathStatus;
 import org.apache.hadoop.registry.client.types.ServiceRecord;
 import org.apache.zookeeper.CreateMode;
@@ -103,10 +105,12 @@ public class RegistryOperationsService extends CuratorService
       int flags) throws IOException {
     Preconditions.checkArgument(record != null, "null record");
     validatePath(path);
+    // validate the record before putting it
+    RegistryTypeUtils.validateServiceRecord(path, record);
     LOG.info("Bound at {} : {}", path, record);
 
     CreateMode mode = CreateMode.PERSISTENT;
-    byte[] bytes = serviceRecordMarshal.toByteswithHeader(record);
+    byte[] bytes = serviceRecordMarshal.toBytes(record);
     zkSet(path, mode, bytes, getClientAcls(),
         ((flags & BindFlags.OVERWRITE) != 0));
   }
@@ -114,7 +118,11 @@ public class RegistryOperationsService extends CuratorService
   @Override
   public ServiceRecord resolve(String path) throws IOException {
     byte[] bytes = zkRead(path);
-    return serviceRecordMarshal.fromBytesWithHeader(path, bytes);
+
+    ServiceRecord record = serviceRecordMarshal.fromBytes(path,
+        bytes, ServiceRecord.RECORD_TYPE);
+    RegistryTypeUtils.validateServiceRecord(path, record);
+    return record;
   }
 
   @Override

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/AddressTypes.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/AddressTypes.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/AddressTypes.java
index 192819c..36dbf0c 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/AddressTypes.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/AddressTypes.java
@@ -38,6 +38,8 @@ public interface AddressTypes {
    * </pre>
    */
   public static final String ADDRESS_HOSTNAME_AND_PORT = "host/port";
+  public static final String ADDRESS_HOSTNAME_FIELD = "host";
+  public static final String ADDRESS_PORT_FIELD = "port";
 
 
   /**

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/Endpoint.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/Endpoint.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/Endpoint.java
index 51418d9..e4effb4 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/Endpoint.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/Endpoint.java
@@ -21,14 +21,16 @@ package org.apache.hadoop.registry.client.types;
 import com.google.common.base.Preconditions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.registry.client.binding.JsonSerDeser;
 import org.apache.hadoop.registry.client.binding.RegistryTypeUtils;
 import org.codehaus.jackson.annotate.JsonIgnoreProperties;
 import org.codehaus.jackson.map.annotate.JsonSerialize;
 
 import java.net.URI;
 import java.util.ArrayList;
-import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 
 /**
  * Description of a single service/component endpoint.
@@ -67,7 +69,7 @@ public final class Endpoint implements Cloneable {
   /**
    * a list of address tuples —tuples whose format depends on the address type
    */
-  public List<List<String>> addresses;
+  public List<Map<String, String>> addresses;
 
   /**
    * Create an empty instance.
@@ -84,10 +86,11 @@ public final class Endpoint implements Cloneable {
     this.api = that.api;
     this.addressType = that.addressType;
     this.protocolType = that.protocolType;
-    this.addresses = new ArrayList<List<String>>(that.addresses.size());
-    for (List<String> address : addresses) {
-      List<String> addr2 = new ArrayList<String>(address.size());
-      Collections.copy(address, addr2);
+    this.addresses = newAddresses(that.addresses.size());
+    for (Map<String, String> address : that.addresses) {
+      Map<String, String> addr2 = new HashMap<String, String>(address.size());
+      addr2.putAll(address);
+      addresses.add(addr2);
     }
   }
 
@@ -101,17 +104,83 @@ public final class Endpoint implements Cloneable {
   public Endpoint(String api,
       String addressType,
       String protocolType,
-      List<List<String>> addrs) {
+      List<Map<String, String>> addrs) {
     this.api = api;
     this.addressType = addressType;
     this.protocolType = protocolType;
-    this.addresses = new ArrayList<List<String>>();
+    this.addresses = newAddresses(0);
     if (addrs != null) {
       addresses.addAll(addrs);
     }
   }
 
   /**
+   * Build an endpoint with an empty address list
+   * @param api API name
+   * @param addressType address type
+   * @param protocolType protocol type
+   */
+  public Endpoint(String api,
+      String addressType,
+      String protocolType) {
+    this.api = api;
+    this.addressType = addressType;
+    this.protocolType = protocolType;
+    this.addresses = newAddresses(0);
+  }
+
+  /**
+   * Build an endpoint with a single address entry.
+   * <p>
+   * This constructor is superfluous given the varags constructor is equivalent
+   * for a single element argument. However, type-erasure in java generics
+   * causes javac to warn about unchecked generic array creation. This
+   * constructor, which represents the common "one address" case, does
+   * not generate compile-time warnings.
+   * @param api API name
+   * @param addressType address type
+   * @param protocolType protocol type
+   * @param addr address. May be null —in which case it is not added
+   */
+  public Endpoint(String api,
+      String addressType,
+      String protocolType,
+      Map<String, String> addr) {
+    this(api, addressType, protocolType);
+    if (addr != null) {
+      addresses.add(addr);
+    }
+  }
+
+  /**
+   * Build an endpoint with a list of addresses
+   * @param api API name
+   * @param addressType address type
+   * @param protocolType protocol type
+   * @param addrs addresses. Null elements will be skipped
+   */
+  public Endpoint(String api,
+      String addressType,
+      String protocolType,
+      Map<String, String>...addrs) {
+    this(api, addressType, protocolType);
+    for (Map<String, String> addr : addrs) {
+      if (addr!=null) {
+        addresses.add(addr);
+      }
+    }
+  }
+
+  /**
+   * Create a new address structure of the requested size
+   * @param size size to create
+   * @return the new list
+   */
+  private List<Map<String, String>> newAddresses(int size) {
+    return new ArrayList<Map<String, String>>(size);
+  }
+
+  /**
    * Build an endpoint from a list of URIs; each URI
    * is ASCII-encoded and added to the list of addresses.
    * @param api API name
@@ -125,40 +194,16 @@ public final class Endpoint implements Cloneable {
     this.addressType = AddressTypes.ADDRESS_URI;
 
     this.protocolType = protocolType;
-    List<List<String>> addrs = new ArrayList<List<String>>(uris.length);
+    List<Map<String, String>> addrs = newAddresses(uris.length);
     for (URI uri : uris) {
-      addrs.add(RegistryTypeUtils.tuple(uri.toString()));
+      addrs.add(RegistryTypeUtils.uri(uri.toString()));
     }
     this.addresses = addrs;
   }
 
   @Override
   public String toString() {
-    final StringBuilder sb = new StringBuilder("Endpoint{");
-    sb.append("api='").append(api).append('\'');
-    sb.append(", addressType='").append(addressType).append('\'');
-    sb.append(", protocolType='").append(protocolType).append('\'');
-
-    sb.append(", addresses=");
-    if (addresses != null) {
-      sb.append("[ ");
-      for (List<String> address : addresses) {
-        sb.append("[ ");
-        if (address == null) {
-          sb.append("NULL entry in address list");
-        } else {
-          for (String elt : address) {
-            sb.append('"').append(elt).append("\" ");
-          }
-        }
-        sb.append("] ");
-      };
-      sb.append("] ");
-    } else {
-      sb.append("(null) ");
-    }
-    sb.append('}');
-    return sb.toString();
+      return marshalToString.toString(this);
   }
 
   /**
@@ -173,7 +218,7 @@ public final class Endpoint implements Cloneable {
     Preconditions.checkNotNull(addressType, "null addressType field");
     Preconditions.checkNotNull(protocolType, "null protocolType field");
     Preconditions.checkNotNull(addresses, "null addresses field");
-    for (List<String> address : addresses) {
+    for (Map<String, String> address : addresses) {
       Preconditions.checkNotNull(address, "null element in address");
     }
   }
@@ -184,7 +229,19 @@ public final class Endpoint implements Cloneable {
    * @throws CloneNotSupportedException
    */
   @Override
-  protected Object clone() throws CloneNotSupportedException {
+  public Object clone() throws CloneNotSupportedException {
     return super.clone();
   }
+
+
+  /**
+   * Static instance of service record marshalling
+   */
+  private static class Marshal extends JsonSerDeser<Endpoint> {
+    private Marshal() {
+      super(Endpoint.class);
+    }
+  }
+
+  private static final Marshal marshalToString = new Marshal();
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ProtocolTypes.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ProtocolTypes.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ProtocolTypes.java
index f225cf0..b836b00 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ProtocolTypes.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ProtocolTypes.java
@@ -34,16 +34,11 @@ public interface ProtocolTypes {
   String PROTOCOL_FILESYSTEM = "hadoop/filesystem";
 
   /**
-   * Classic Hadoop IPC : {@value}.
+   * Hadoop IPC,  "classic" or protobuf : {@value}.
    */
   String PROTOCOL_HADOOP_IPC = "hadoop/IPC";
 
   /**
-   * Hadoop protocol buffers IPC: {@value}.
-   */
-  String PROTOCOL_HADOOP_IPC_PROTOBUF = "hadoop/protobuf";
-
-  /**
    * Corba IIOP: {@value}.
    */
   String PROTOCOL_IIOP = "IIOP";

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecord.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecord.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecord.java
index 378127f..9403d31 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecord.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecord.java
@@ -21,6 +21,7 @@ package org.apache.hadoop.registry.client.types;
 import com.google.common.base.Preconditions;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
 import org.codehaus.jackson.annotate.JsonAnyGetter;
 import org.codehaus.jackson.annotate.JsonAnySetter;
 import org.codehaus.jackson.map.annotate.JsonSerialize;
@@ -41,6 +42,17 @@ import java.util.Map;
 public class ServiceRecord implements Cloneable {
 
   /**
+   * A type string which MUST be in the serialized json. This permits
+   * fast discarding of invalid entries
+   */
+  public static final String RECORD_TYPE = "JSONServiceRecord";
+
+  /**
+   * The type field. This must be the string {@link #RECORD_TYPE}
+   */
+  public String type = RECORD_TYPE;
+
+  /**
    * Description string
    */
   public String description;
@@ -233,17 +245,5 @@ public class ServiceRecord implements Cloneable {
     return super.clone();
   }
 
-  /**
-   * Validate the record by checking for null fields and other invalid
-   * conditions
-   * @throws NullPointerException if a field is null when it
-   * MUST be set.
-   * @throws RuntimeException on invalid entries
-   */
-  public void validate() {
-    for (Endpoint endpoint : external) {
-      Preconditions.checkNotNull("null endpoint", endpoint);
-      endpoint.validate();
-    }
-  }
+
 }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecordHeader.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecordHeader.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecordHeader.java
deleted file mode 100644
index 2f75dba..0000000
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/java/org/apache/hadoop/registry/client/types/ServiceRecordHeader.java
+++ /dev/null
@@ -1,59 +0,0 @@
-/*
- * Licensed to the Apache Software Foundation (ASF) under one
- * or more contributor license agreements.  See the NOTICE file
- * distributed with this work for additional information
- * regarding copyright ownership.  The ASF licenses this file
- * to you under the Apache License, Version 2.0 (the
- * "License"); you may not use this file except in compliance
- * with the License.  You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.hadoop.registry.client.types;
-
-import org.apache.hadoop.classification.InterfaceAudience;
-import org.apache.hadoop.classification.InterfaceStability;
-
-/**
- * Service record header; access to the byte array kept private
- * to avoid findbugs warnings of mutability
- */
-@InterfaceAudience.Public
-@InterfaceStability.Evolving
-public class ServiceRecordHeader {
-  /**
-   * Header of a service record:  "jsonservicerec"
-   * By making this over 12 bytes long, we can auto-determine which entries
-   * in a listing are too short to contain a record without getting their data
-   */
-  private static final byte[] RECORD_HEADER = {
-      'j', 's', 'o', 'n',
-      's', 'e', 'r', 'v', 'i', 'c', 'e',
-      'r', 'e', 'c'
-  };
-
-  /**
-   * Get the length of the record header
-   * @return the header length
-   */
-  public static int getLength() {
-    return RECORD_HEADER.length;
-  }
-
-  /**
-   * Get a clone of the record header
-   * @return the new record header.
-   */
-  public static byte[] getData() {
-    byte[] h = new byte[RECORD_HEADER.length];
-    System.arraycopy(RECORD_HEADER, 0, h, 0, RECORD_HEADER.length);
-    return h;
-  }
-}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/tla/yarnregistry.tla
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/tla/yarnregistry.tla b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/tla/yarnregistry.tla
index 1c19ade..a950475 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/tla/yarnregistry.tla
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/main/tla/yarnregistry.tla
@@ -4,6 +4,7 @@ EXTENDS FiniteSets, Sequences, Naturals, TLC
 
 
 (*
+============================================================================
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
@@ -19,6 +20,7 @@ EXTENDS FiniteSets, Sequences, Naturals, TLC
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
+============================================================================
  *)
 
 (*
@@ -71,13 +73,22 @@ CONSTANTS
     MknodeActions    \* all possible mkdir actions
 
 
+ASSUME PathChars \in STRING
+ASSUME Paths \in STRING
+
+(* Data in records is JSON, hence a string *)
+ASSUME Data \in STRING
+
+----------------------------------------------------------------------------------------
 
 (* the registry*)
 VARIABLE registry
 
+
 (* Sequence of actions to apply to the registry *)
 VARIABLE actions
 
+
 ----------------------------------------------------------------------------------------
 (* Tuple of all variables.  *)
 
@@ -92,7 +103,6 @@ vars == << registry, actions >>
 
 (* Persistence policy *)
 PersistPolicySet == {
-    "",                      \* Undefined; field not present. PERMANENT is implied.
     "permanent",            \* persists until explicitly removed
     "application",          \* persists until the application finishes
     "application-attempt",  \* persists until the application attempt finishes
@@ -104,7 +114,6 @@ TypeInvariant ==
     /\ \A p \in PersistPolicies: p \in PersistPolicySet
 
 
-
 ----------------------------------------------------------------------------------------
 
 
@@ -129,6 +138,14 @@ RegistryEntry == [
     ]
 
 
+(* Define the set of all string to string mappings *)
+
+StringMap == [
+  STRING |-> STRING
+]
+
+
+
 (*
     An endpoint in a service record
 *)
@@ -140,21 +157,14 @@ Endpoint == [
     addresses: Addresses
 ]
 
-(* Attributes are the set of all string to string mappings *)
-
-Attributes == [
-STRING |-> STRING
-]
-
 (*
     A service record
 *)
 ServiceRecord == [
-    \* ID -used when applying the persistence policy
-    yarn_id: STRING,
 
-    \* the persistence policy
-    yarn_persistence: PersistPolicySet,
+    \* This MUST be present: if it is not then the data is not a service record
+    \* This permits shortcut scan & reject of byte arrays without parsing
+    type: "JSONServiceRecord",
 
     \*A description
     description: STRING,
@@ -166,9 +176,34 @@ ServiceRecord == [
     internal: Endpoints,
 
     \* Attributes are a function
-    attributes: Attributes
+    attributes: StringMap
 ]
 
+----------------------------------------------------------------------------------------
+
+(*
+ There is an operation serialize whose internals are not defined,
+ Which converts the service records to JSON
+ *)
+
+CONSTANT serialize(_)
+
+(* A function which returns true iff the byte stream is considered a valid service record. *)
+CONSTANT containsServiceRecord(_)
+
+(* A function to deserialize a string to JSON *)
+CONSTANT deserialize(_)
+
+ASSUME \A json \in STRING: containsServiceRecord(json) \in BOOLEAN
+
+(* Records can be serialized *)
+ASSUME \A r \in ServiceRecord : serialize(r) \in STRING /\ containsServiceRecord(serialize(r))
+
+(* All strings for which containsServiceRecord() holds can be deserialized *)
+ASSUME \A json \in STRING: containsServiceRecord(json) => deserialize(json) \in ServiceRecord
+
+
+
 
 ----------------------------------------------------------------------------------------
 
@@ -304,8 +339,8 @@ validRegistry(R) ==
         \* an entry must be the root entry or have a parent entry
         /\ \A e \in R: isRootEntry(e) \/ exists(R, parent(e.path))
 
-        \* If the entry has data, it must be a service record
-        /\ \A e \in R: (e.data = << >> \/ e.data \in ServiceRecords)
+        \* If the entry has data, it must contain a service record
+        /\ \A e \in R: (e.data = << >> \/ containsServiceRecord(e.data))
 
 
 ----------------------------------------------------------------------------------------
@@ -336,13 +371,13 @@ mknode() adds a new empty entry where there was none before, iff
 *)
 
 mknodeSimple(R, path) ==
-    LET record == [ path |-> path, data |-> <<>>  ]
+    LET entry == [ path |-> path, data |-> <<>>  ]
     IN  \/ exists(R, path)
-        \/ (exists(R, parent(path))  /\ canBind(R, record) /\ (R' = R \union {record} ))
+        \/ (exists(R, parent(path))  /\ canBind(R, entry) /\ (R' = R \union {entry} ))
 
 
 (*
-For all parents, the mknodeSimpl() criteria must apply.
+For all parents, the mknodeSimple() criteria must apply.
 This could be defined recursively, though as TLA+ does not support recursion,
 an alternative is required
 
@@ -350,7 +385,8 @@ an alternative is required
 Because this specification is declaring the final state of a operation, not
 the implemental, all that is needed is to describe those parents.
 
-It declares that the mkdirSimple state applies to the path and all its parents in the set R'
+It declares that the mknodeSimple() state applies to the path and all
+its parents in the set R'
 
 *)
 mknodeWithParents(R, path) ==
@@ -402,7 +438,7 @@ purge(R, path, id, persistence) ==
          => recursiveDelete(R, p2.path)
 
 (*
-resolveRecord() resolves the record at a path or fails.
+resolveEntry() resolves the record entry at a path or fails.
 
 It relies on the fact that if the cardinality of a set is 1, then the CHOOSE operator
 is guaranteed to return the single entry of that set, iff the choice predicate holds.
@@ -411,19 +447,28 @@ Using a predicate of TRUE, it always succeeds, so this function selects
 the sole entry of the resolve operation.
 *)
 
-resolveRecord(R, path) ==
+resolveEntry(R, path) ==
     LET l == resolve(R, path) IN
         /\ Cardinality(l) = 1
         /\ CHOOSE e \in l : TRUE
 
 (*
+ Resolve a record by resolving the entry and deserializing the result
+ *)
+resolveRecord(R, path) ==
+    deserialize(resolveEntry(R, path))
+
+
+(*
 The specific action of putting an entry into a record includes validating the record
 *)
 
 validRecordToBind(path, record) ==
       \* The root entry must have permanent persistence
-     isRootPath(path) => (record.attributes["yarn:persistence"] = "permanent"
-     \/ record.attributes["yarn:persistence"] = "")
+     isRootPath(path) => (
+        record.attributes["yarn:persistence"] = "permanent"
+        \/ record.attributes["yarn:persistence"]
+        \/ record.attributes["yarn:persistence"] = {})
 
 
 (*
@@ -432,13 +477,12 @@ marshalled as the data in the entry
  *)
 bindRecord(R, path, record) ==
     /\ validRecordToBind(path, record)
-    /\ bind(R, [path |-> path, data |-> record])
+    /\ bind(R, [path |-> path, data |-> serialize(record)])
 
 
 ----------------------------------------------------------------------------------------
 
 
-
 (*
 The action queue can only contain one of the sets of action types, and
 by giving each a unique name, those sets are guaranteed to be disjoint

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/RegistryTestHelper.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/RegistryTestHelper.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/RegistryTestHelper.java
index 460ecad..91602e1 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/RegistryTestHelper.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/RegistryTestHelper.java
@@ -20,7 +20,6 @@ package org.apache.hadoop.registry;
 
 import org.apache.commons.lang.StringUtils;
 import org.apache.hadoop.security.UserGroupInformation;
-import org.apache.hadoop.util.Shell;
 import org.apache.hadoop.registry.client.api.RegistryConstants;
 import org.apache.hadoop.registry.client.binding.RegistryUtils;
 import org.apache.hadoop.registry.client.binding.RegistryTypeUtils;
@@ -46,11 +45,7 @@ import java.net.URISyntaxException;
 import java.util.List;
 import java.util.Map;
 
-import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.inetAddrEndpoint;
-import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.ipcEndpoint;
-import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.restEndpoint;
-import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.tuple;
-import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.webEndpoint;
+import static org.apache.hadoop.registry.client.binding.RegistryTypeUtils.*;
 
 /**
  * This is a set of static methods to aid testing the registry operations.
@@ -61,18 +56,18 @@ public class RegistryTestHelper extends Assert {
   public static final String SC_HADOOP = "org-apache-hadoop";
   public static final String USER = "devteam/";
   public static final String NAME = "hdfs";
-  public static final String API_WEBHDFS = "org_apache_hadoop_namenode_webhdfs";
-  public static final String API_HDFS = "org_apache_hadoop_namenode_dfs";
+  public static final String API_WEBHDFS = "classpath:org.apache.hadoop.namenode.webhdfs";
+  public static final String API_HDFS = "classpath:org.apache.hadoop.namenode.dfs";
   public static final String USERPATH = RegistryConstants.PATH_USERS + USER;
   public static final String PARENT_PATH = USERPATH + SC_HADOOP + "/";
   public static final String ENTRY_PATH = PARENT_PATH + NAME;
-  public static final String NNIPC = "nnipc";
-  public static final String IPC2 = "IPC2";
+  public static final String NNIPC = "uuid:423C2B93-C927-4050-AEC6-6540E6646437";
+  public static final String IPC2 = "uuid:0663501D-5AD3-4F7E-9419-52F5D6636FCF";
   private static final Logger LOG =
       LoggerFactory.getLogger(RegistryTestHelper.class);
-  public static final String KTUTIL = "ktutil";
   private static final RegistryUtils.ServiceRecordMarshal recordMarshal =
       new RegistryUtils.ServiceRecordMarshal();
+  public static final String HTTP_API = "http://";
 
   /**
    * Assert the path is valid by ZK rules
@@ -148,9 +143,9 @@ public class RegistryTestHelper extends Assert {
     assertEquals(API_WEBHDFS, webhdfs.api);
     assertEquals(AddressTypes.ADDRESS_URI, webhdfs.addressType);
     assertEquals(ProtocolTypes.PROTOCOL_REST, webhdfs.protocolType);
-    List<List<String>> addressList = webhdfs.addresses;
-    List<String> url = addressList.get(0);
-    String addr = url.get(0);
+    List<Map<String, String>> addressList = webhdfs.addresses;
+    Map<String, String> url = addressList.get(0);
+    String addr = url.get("uri");
     assertTrue(addr.contains("http"));
     assertTrue(addr.contains(":8020"));
 
@@ -159,8 +154,9 @@ public class RegistryTestHelper extends Assert {
         nnipc.protocolType);
 
     Endpoint ipc2 = findEndpoint(record, IPC2, false, 1,2);
+    assertNotNull(ipc2);
 
-    Endpoint web = findEndpoint(record, "web", true, 1, 1);
+    Endpoint web = findEndpoint(record, HTTP_API, true, 1, 1);
     assertEquals(1, web.addresses.size());
     assertEquals(1, web.addresses.get(0).size());
   }
@@ -275,14 +271,14 @@ public class RegistryTestHelper extends Assert {
   public static void addSampleEndpoints(ServiceRecord entry, String hostname)
       throws URISyntaxException {
     assertNotNull(hostname);
-    entry.addExternalEndpoint(webEndpoint("web",
+    entry.addExternalEndpoint(webEndpoint(HTTP_API,
         new URI("http", hostname + ":80", "/")));
     entry.addExternalEndpoint(
         restEndpoint(API_WEBHDFS,
             new URI("http", hostname + ":8020", "/")));
 
-    Endpoint endpoint = ipcEndpoint(API_HDFS, true, null);
-    endpoint.addresses.add(tuple(hostname, "8030"));
+    Endpoint endpoint = ipcEndpoint(API_HDFS, null);
+    endpoint.addresses.add(RegistryTypeUtils.hostnamePortPair(hostname, 8030));
     entry.addInternalEndpoint(endpoint);
     InetSocketAddress localhost = new InetSocketAddress("localhost", 8050);
     entry.addInternalEndpoint(
@@ -290,9 +286,7 @@ public class RegistryTestHelper extends Assert {
             8050));
     entry.addInternalEndpoint(
         RegistryTypeUtils.ipcEndpoint(
-            IPC2,
-            true,
-            RegistryTypeUtils.marshall(localhost)));
+            IPC2, localhost));
   }
 
   /**

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/client/binding/TestMarshalling.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/client/binding/TestMarshalling.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/client/binding/TestMarshalling.java
index 14e3b1f..f1814d3 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/client/binding/TestMarshalling.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/client/binding/TestMarshalling.java
@@ -19,9 +19,9 @@
 package org.apache.hadoop.registry.client.binding;
 
 import org.apache.hadoop.registry.RegistryTestHelper;
+import org.apache.hadoop.registry.client.exceptions.InvalidRecordException;
 import org.apache.hadoop.registry.client.exceptions.NoRecordException;
 import org.apache.hadoop.registry.client.types.ServiceRecord;
-import org.apache.hadoop.registry.client.types.ServiceRecordHeader;
 import org.apache.hadoop.registry.client.types.yarn.PersistencePolicies;
 import org.junit.BeforeClass;
 import org.junit.Rule;
@@ -31,8 +31,6 @@ import org.junit.rules.Timeout;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.EOFException;
-
 /**
  * Test record marshalling
  */
@@ -44,6 +42,7 @@ public class TestMarshalling extends RegistryTestHelper {
   public final Timeout testTimeout = new Timeout(10000);
   @Rule
   public TestName methodName = new TestName();
+
   private static RegistryUtils.ServiceRecordMarshal marshal;
 
   @BeforeClass
@@ -55,42 +54,65 @@ public class TestMarshalling extends RegistryTestHelper {
   public void testRoundTrip() throws Throwable {
     String persistence = PersistencePolicies.PERMANENT;
     ServiceRecord record = createRecord(persistence);
-    record.set("customkey","customvalue");
-    record.set("customkey2","customvalue2");
+    record.set("customkey", "customvalue");
+    record.set("customkey2", "customvalue2");
+    RegistryTypeUtils.validateServiceRecord("", record);
     LOG.info(marshal.toJson(record));
     byte[] bytes = marshal.toBytes(record);
-    ServiceRecord r2 = marshal.fromBytes("", bytes, 0);
+    ServiceRecord r2 = marshal.fromBytes("", bytes);
     assertMatches(record, r2);
+    RegistryTypeUtils.validateServiceRecord("", r2);
   }
 
-  @Test
-  public void testRoundTripHeaders() throws Throwable {
-    ServiceRecord record = createRecord(PersistencePolicies.CONTAINER);
-    byte[] bytes = marshal.toByteswithHeader(record);
-    ServiceRecord r2 = marshal.fromBytesWithHeader("", bytes);
-    assertMatches(record, r2);
 
+  @Test(expected = NoRecordException.class)
+  public void testUnmarshallNoData() throws Throwable {
+    marshal.fromBytes("src", new byte[]{});
   }
 
   @Test(expected = NoRecordException.class)
-  public void testRoundTripBadHeaders() throws Throwable {
-    ServiceRecord record = createRecord(PersistencePolicies.APPLICATION);
-    byte[] bytes = marshal.toByteswithHeader(record);
-    bytes[1] = 0x01;
-    marshal.fromBytesWithHeader("src", bytes);
+  public void testUnmarshallNotEnoughData() throws Throwable {
+    // this is nominally JSON -but without the service record header
+    marshal.fromBytes("src", new byte[]{'{','}'}, ServiceRecord.RECORD_TYPE);
+  }
+
+  @Test(expected = InvalidRecordException.class)
+  public void testUnmarshallNoBody() throws Throwable {
+    byte[] bytes = "this is not valid JSON at all and should fail".getBytes();
+    marshal.fromBytes("src", bytes);
+  }
+
+  @Test(expected = InvalidRecordException.class)
+  public void testUnmarshallWrongType() throws Throwable {
+    byte[] bytes = "{'type':''}".getBytes();
+    ServiceRecord serviceRecord = marshal.fromBytes("marshalling", bytes);
+    RegistryTypeUtils.validateServiceRecord("validating", serviceRecord);
   }
 
   @Test(expected = NoRecordException.class)
-  public void testUnmarshallHeaderTooShort() throws Throwable {
-    marshal.fromBytesWithHeader("src", new byte[]{'a'});
+  public void testUnmarshallWrongLongType() throws Throwable {
+    ServiceRecord record = new ServiceRecord();
+    record.type = "ThisRecordHasALongButNonMatchingType";
+    byte[] bytes = marshal.toBytes(record);
+    ServiceRecord serviceRecord = marshal.fromBytes("marshalling",
+        bytes, ServiceRecord.RECORD_TYPE);
   }
 
-  @Test(expected = EOFException.class)
-  public void testUnmarshallNoBody() throws Throwable {
-    byte[] bytes = ServiceRecordHeader.getData();
-    marshal.fromBytesWithHeader("src", bytes);
+  @Test(expected = NoRecordException.class)
+  public void testUnmarshallNoType() throws Throwable {
+    ServiceRecord record = new ServiceRecord();
+    record.type = "NoRecord";
+    byte[] bytes = marshal.toBytes(record);
+    ServiceRecord serviceRecord = marshal.fromBytes("marshalling",
+        bytes, ServiceRecord.RECORD_TYPE);
   }
 
+  @Test(expected = InvalidRecordException.class)
+  public void testRecordValidationWrongType() throws Throwable {
+    ServiceRecord record = new ServiceRecord();
+    record.type = "NotAServiceRecordType";
+    RegistryTypeUtils.validateServiceRecord("validating", record);
+  }
 
   @Test
   public void testUnknownFieldsRoundTrip() throws Throwable {
@@ -102,8 +124,8 @@ public class TestMarshalling extends RegistryTestHelper {
     assertEquals("2", record.get("intval"));
     assertNull(record.get("null"));
     assertEquals("defval", record.get("null", "defval"));
-    byte[] bytes = marshal.toByteswithHeader(record);
-    ServiceRecord r2 = marshal.fromBytesWithHeader("", bytes);
+    byte[] bytes = marshal.toBytes(record);
+    ServiceRecord r2 = marshal.fromBytes("", bytes);
     assertEquals("value", r2.get("key"));
     assertEquals("2", r2.get("intval"));
   }

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/operations/TestRegistryOperations.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/operations/TestRegistryOperations.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/operations/TestRegistryOperations.java
index 7a7f88c..853d7f1 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/operations/TestRegistryOperations.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-registry/src/test/java/org/apache/hadoop/registry/operations/TestRegistryOperations.java
@@ -23,6 +23,7 @@ import org.apache.hadoop.fs.PathIsNotEmptyDirectoryException;
 import org.apache.hadoop.fs.PathNotFoundException;
 import org.apache.hadoop.registry.AbstractRegistryTest;
 import org.apache.hadoop.registry.client.api.BindFlags;
+import org.apache.hadoop.registry.client.binding.RegistryTypeUtils;
 import org.apache.hadoop.registry.client.binding.RegistryUtils;
 import org.apache.hadoop.registry.client.binding.RegistryPathUtils;
 import org.apache.hadoop.registry.client.exceptions.NoRecordException;
@@ -91,10 +92,8 @@ public class TestRegistryOperations extends AbstractRegistryTest {
             childStats.values());
     assertEquals(1, records.size());
     ServiceRecord record = records.get(ENTRY_PATH);
-    assertNotNull(record);
-    record.validate();
+    RegistryTypeUtils.validateServiceRecord(ENTRY_PATH, record);
     assertMatches(written, record);
-
   }
 
   @Test

http://git-wip-us.apache.org/repos/asf/hadoop/blob/e333584c/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/registry/yarn-registry.md
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/registry/yarn-registry.md b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/registry/yarn-registry.md
index a2a5009..b38d9fb 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/registry/yarn-registry.md
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/registry/yarn-registry.md
@@ -353,6 +353,10 @@ application.
         <td>Description</td>
       </tr>
       <tr>
+        <td>type: String</td>
+        <td>Always: "JSONServiceRecord"</td>
+      </tr>
+      <tr>
         <td>description: String</td>
         <td>Human-readable description.</td>
       </tr>
@@ -366,6 +370,8 @@ application.
       </tr>
     </table>
 
+The type field MUST be `"JSONServiceRecord"`. Mandating this string allows future record types *and* permits rapid rejection of byte arrays that lack this string before attempting JSON parsing.
+
 ### YARN Persistence policies
 
 The YARN Resource Manager integration integrates cleanup of service records
@@ -379,7 +385,6 @@ any use of the registry without the RM's participation.
 The attributes, `yarn:id` and `yarn:persistence` specify which records
 *and any child entries* may be deleted as the associated YARN components complete.
 
-
 The `yarn:id` field defines the application, attempt or container ID to match;
 the `yarn:persistence` attribute defines the trigger for record cleanup, and
 implicitly the type of the contents of the `yarn:id` field.
@@ -432,31 +437,32 @@ up according the lifecycle of that application.
     <td>Description</td>
   </tr>
   <tr>
-    <td>addresses: List[List[String]]</td>
-    <td>a list of address tuples whose format depends on the address type</td>
-  </tr>
-  <tr>
-    <td>addressType: String</td>
-    <td>format of the binding</td>
-  </tr>
+    <td>api: URI as String</td>
+    <td>API implemented at the end of the binding</td>
   <tr>
     <td>protocol: String</td>
     <td>Protocol. Examples:
 `http`, `https`, `hadoop-rpc`, `zookeeper`, `web`, `REST`, `SOAP`, ...</td>
   </tr>
   <tr>
-    <td>api: String</td>
-    <td>API implemented at the end of the binding</td>
+    <td>addressType: String</td>
+    <td>format of the binding</td>
   </tr>
+  </tr>
+    <tr>
+    <td>addresses: List[Map[String, String]]</td>
+    <td>a list of address maps</td>
+  </tr>
+
 </table>
 
 
 All string fields have a limit on size, to dissuade services from hiding
 complex JSON structures in the text description.
 
-### Field: Address Type
+#### Field `addressType`: Address Type
 
-The addressType field defines the string format of entries.
+The `addressType` field defines the string format of entries.
 
 Having separate types is that tools (such as a web viewer) can process binding
 strings without having to recognize the protocol.
@@ -467,43 +473,58 @@ strings without having to recognize the protocol.
     <td>binding format</td>
   </tr>
   <tr>
-    <td>`url`</td>
-    <td>`[URL]`</td>
+    <td>uri</td>
+    <td>uri:URI of endpoint</td>
   </tr>
   <tr>
-    <td>`hostname`</td>
-    <td>`[hostname]`</td>
+    <td>hostname</td>
+    <td>hostname: service host</td>
   </tr>
   <tr>
-    <td>`inetaddress`</td>
-    <td>`[hostname, port]`</td>
+    <td>inetaddress</td>
+    <td>hostname: service host, port: service port</td>
   </tr>
   <tr>
-    <td>`path`</td>
-    <td>`[/path/to/something]`</td>
+    <td>path</td>
+    <td>path: generic unix filesystem path</td>
   </tr>
   <tr>
-    <td>`zookeeper`</td>
-    <td>`[quorum-entry, path]`</td>
+    <td>zookeeper</td>
+    <td>hostname: service host, port: service port, path: ZK path</td>
   </tr>
 </table>
 
 
-An actual zookeeper binding consists of a list of `hostname:port` bindings –the
-quorum— and the path within. In the proposed schema, every quorum entry will be
-listed as a triple of `[hostname, port, path]`. Client applications do not
-expect the path to de be different across the quorum. The first entry in the
-list of quorum hosts MUST define the path to be used by all clients. Later
-entries SHOULD list the same path, though clients MUST ignore these.
+In the zookeeper binding, every entry represents a single node in quorum,
+the `hostname` and `port` fields defining the hostname of the ZK instance
+and the port on which it is listening. The `path` field lists zookeeper path
+for applications to use. For example, for HBase this would refer to the znode
+containing information about the HBase cluster.
+
+The path MUST be identical across all address elements in the `addresses` list.
+This ensures that any single address contains enough information to connect
+to the quorum and connect to the relevant znode.
 
 New Address types may be defined; if not standard please prefix with the
 character sequence `"x-"`.
 
-#### **Field: API**
+### Field `api`: API identifier
+
+The API field MUST contain a URI that identifies the specific API of an endpoint.
+These MUST be unique to an API to avoid confusion.
+
+The following strategies are suggested to provide unique URIs for an API
+
+1. The SOAP/WS-* convention of using the URL to where the WSDL defining the service
+2. A URL to the svn/git hosted document defining a REST API
+3. the `classpath` schema followed by a path to a class or package in an application.
+4. The `uuid` schema with a generated UUID.
+
+It is hoped that standard API URIs will be defined for common APIs. Two such non-normative APIs are used in this document
+
+* `http://` : A web site for humans
+* `classpath:javax.management.jmx`: and endpoint supporting the JMX management protocol (RMI-based)
 
-APIs may be unique to a service class, or may be common across by service
-classes. They MUST be given unique names. These MAY be based on service
-packages but MAY be derived from other naming schemes:
 
 ### Examples of Service Entries
 
@@ -524,12 +545,14 @@ overall application. It exports the URL to a load balancer.
 
     {
       "description" : "tomcat-based web application",
-      "registrationTime" : 1408638082444,
       "external" : [ {
-        "api" : "www",
+        "api" : "http://internal.example.org/restapis/scheduler/20141026v1",
         "addressType" : "uri",
-        "protocolType" : "REST",
-        "addresses" : [ [ "http://loadbalancer/" ] [ "http://loadbalancer2/" ] ]
+        "protocol" : "REST",
+        "addresses" : [
+         { "uri" : "http://loadbalancer/" },
+         { "uri" : "http://loadbalancer2/" }
+          ]
       } ],
       "internal" : [ ]
     }
@@ -545,21 +568,23 @@ will trigger the deletion of this entry
     /users/devteam/org-apache-tomcat/test1/components/container-1408631738011-0001-01-000001
 
     {
-      "registrationTime" : 1408638082445,
       "yarn:id" : "container_1408631738011_0001_01_000001",
-      "yarn:persistence" : "3",
-      "description" : null,
+      "yarn:persistence" : "container",
+      "description" : "",
       "external" : [ {
-        "api" : "www",
+        "api" : "http://internal.example.org/restapis/scheduler/20141026v1",
         "addressType" : "uri",
-        "protocolType" : "REST",
-        "addresses" : [ [ "http://rack4server3:43572" ] ]
+        "protocol" : "REST",
+        "addresses" : [{ "uri" : "rack4server3:43572" }  ]
       } ],
       "internal" : [ {
-        "api" : "jmx",
+        "api" : "classpath:javax.management.jmx",
         "addressType" : "host/port",
-        "protocolType" : "JMX",
-        "addresses" : [ [ "rack4server3", "43573" ] ]
+        "protocol" : "rmi",
+        "addresses" : [ {
+          "host" : "rack4server3",
+          "port" : "48551"
+        } ]
       } ]
     }
 
@@ -571,19 +596,22 @@ external endpoint, the JMX addresses as internal.
     {
       "registrationTime" : 1408638082445,
       "yarn:id" : "container_1408631738011_0001_01_000002",
-      "yarn:persistence" : "3",
+      "yarn:persistence" : "container",
       "description" : null,
       "external" : [ {
-        "api" : "www",
+        "api" : "http://internal.example.org/restapis/scheduler/20141026v1",
         "addressType" : "uri",
-        "protocolType" : "REST",
+        "protocol" : "REST",
         "addresses" : [ [ "http://rack1server28:35881" ] ]
       } ],
       "internal" : [ {
-        "api" : "jmx",
+        "api" : "classpath:javax.management.jmx",
         "addressType" : "host/port",
-        "protocolType" : "JMX",
-        "addresses" : [ [ "rack1server28", "35882" ] ]
+        "protocol" : "rmi",
+        "addresses" : [ {
+          "host" : "rack1server28",
+          "port" : "48551"
+        } ]
       } ]
     }
 
@@ -887,3 +915,106 @@ Implementations may throttle update operations.
 **Rate of Polling**
 
 Clients which poll the registry may be throttled.
+
+# Complete service record example
+
+Below is a (non-normative) example of a service record retrieved
+from a YARN application.
+
+
+    {
+      "type" : "JSONServiceRecord",
+      "description" : "Slider Application Master",
+      "yarn:persistence" : "application",
+      "yarn:id" : "application_1414052463672_0028",
+      "external" : [ {
+        "api" : "classpath:org.apache.slider.appmaster",
+        "addressType" : "host/port",
+        "protocol" : "hadoop/IPC",
+        "addresses" : [ {
+          "port" : "48551",
+          "host" : "nn.example.com"
+        } ]
+      }, {
+        "api" : "http://",
+        "addressType" : "uri",
+        "protocol" : "web",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.management",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743/ws/v1/slider/mgmt"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.publisher",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743/ws/v1/slider/publisher"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.registry",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743/ws/v1/slider/registry"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.publisher.configurations",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743/ws/v1/slider/publisher/slider"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.publisher.exports",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "http://nn.example.com:40743/ws/v1/slider/publisher/exports"
+        } ]
+      } ],
+      "internal" : [ {
+        "api" : "classpath:org.apache.slider.agents.secure",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "https://nn.example.com:52705/ws/v1/slider/agents"
+        } ]
+      }, {
+        "api" : "classpath:org.apache.slider.agents.oneway",
+        "addressType" : "uri",
+        "protocol" : "REST",
+        "addresses" : [ {
+          "uri" : "https://nn.example.com:33425/ws/v1/slider/agents"
+        } ]
+      } ]
+    }
+
+It publishes a number of endpoints, both internal and external.
+
+External:
+
+1. The IPC hostname and port for client-AM communications
+1. URL to the AM's web UI
+1. A series of REST URLs under the web UI for specific application services.
+The details are irrelevant —note that they use an application-specific API
+value to ensure uniqueness.
+
+Internal:
+1. Two URLS to REST APIs offered by the AM for containers deployed by
+ the application itself.
+
+Python agents running in the containers retrieve the internal endpoint
+URLs to communicate with their AM. The record is resolved on container startup
+and cached until communications problems occur. At that point the registry is
+queried for the current record, then an attempt is made to reconnect to the AM.
+
+Here "connectivity" problems means both "low level socket/IO errors" and
+"failures in HTTPS authentication". The agents use two-way HTTPS authentication
+—if the AM fails and another application starts listening on the same ports
+it will trigger an authentication failure and hence service record reread.


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