[ https://issues.apache.org/jira/browse/HADOOP-6904?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Hairong Kuang updated HADOOP-6904:
----------------------------------
Attachment: majorMinorVersion1.patch
A new patch is attached. This is a little bit different from Sanjay's summary:
1. getProxy or waitProxy returns an object that contains the reference to the RPC proxy and
the server version #. The caller of getProxy/waitProxy could cache the server version# by
itself.
2. getProtocolVersion will always get the server version from the server side.
Returning methods that supported at the server side along with getProtocolVersion is a good
solution to support across branch client/server RPCs. Dhruba is especially interested in this
approach. Lets get back to this after we put more thoughts. For this jira, I prefer to go
with the version# for now.
> A baby step towards inter-version communications between dfs client and NameNode
> --------------------------------------------------------------------------------
>
> Key: HADOOP-6904
> URL: https://issues.apache.org/jira/browse/HADOOP-6904
> Project: Hadoop Common
> Issue Type: New Feature
> Components: ipc
> Affects Versions: 0.22.0
> Reporter: Hairong Kuang
> Assignee: Hairong Kuang
> Fix For: 0.22.0
>
> Attachments: majorMinorVersion.patch, majorMinorVersion1.patch, rpcVersion.patch,
rpcVersion1.patch
>
>
> Currently RPC communications in Hadoop is very strict. If a client has a different version
from that of the server, a VersionMismatched exception is thrown and the client can not connect
to the server. This force us to update both client and server all at once if a RPC protocol
is changed. But sometime different versions do not mean the client & server are not compatible.
It would be nice if we could relax this restriction and allows us to support inter-version
communications.
> My idea is that DfsClient catches VersionMismatched exception when it connects to NameNode.
It then checks if the client & the server is compatible. If yes, it sets the NameNode
version in the dfs client and allows the client to continue talking to NameNode. Otherwise,
rethrow the VersionMismatch exception.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
|