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From "Doug Cutting (JIRA)" <j...@apache.org>
Subject [jira] Commented: (HADOOP-4348) Adding service-level authorization to Hadoop
Date Thu, 23 Oct 2008 20:22:44 GMT

    [ https://issues.apache.org/jira/browse/HADOOP-4348?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12642260#action_12642260
] 

Doug Cutting commented on HADOOP-4348:
--------------------------------------

Sanjay, I'm fine adding a session layer someday.  That would probably be useful.

Much of what you speak of is authentication, which may have to be session based rather than
per-message.  But, so far as I can see, service-level authorization belongs somewhere between
our two existing layers, so we need to choose one, rather arbitrarily.  My initial observation
was merely, with the two layers we have now, it would be more simply implemented at the RPC
layer.  Looking at the patch, i think would take fewer lines of easier-to-read code to implement
this feature there.  (Compare earlier with later versions of HADOOP-4049.)  Authorization,
as specified in this issue, requires just a lookup of the username and group in a hashtable,
so performance should not be an issue.

So if we want to add service-level authorization now, without first re-architecting things,
and we don't see a strong performance or functionality reason against checking service-level
authorization per-request, then we should put it at the RPC layer.  If we later re-architect
things into more layers, as we probably should, then service-level authorization will end
up in some new, intermediate layer.

My initial comments were a response to the patch, not an architectural treaty.  Let's keep
things grounded in code.  If someone wants to re-architect RPC in this patch, that's fine.
 But until then, we need to decide how to fit the desired feature into the existing code while
making the least mess.  If someone can contribute a patch which implements this feature as
cleanly and simply at the IPC level alone as I think it can be done at the RPC level that'd
be great.

> Adding service-level authorization to Hadoop
> --------------------------------------------
>
>                 Key: HADOOP-4348
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4348
>             Project: Hadoop Core
>          Issue Type: New Feature
>            Reporter: Kan Zhang
>            Assignee: Arun C Murthy
>             Fix For: 0.20.0
>
>         Attachments: HADOOP-4348_0_20081022.patch, jaas_service_v1.patch
>
>
> Service-level authorization is the initial checking done by a Hadoop service to find
out if a connecting client is a pre-defined user of that service. If not, the connection or
service request will be declined. This feature allows services to limit access to a clearly
defined group of users. For example, service-level authorization allows "world-readable" files
on a HDFS cluster to be readable only by the pre-defined users of that cluster, not by anyone
who can connect to the cluster. It also allows a M/R cluster to define its group of users
so that only those users can submit jobs to it.
> Here is an initial list of requirements I came up with.
>     1. Users of a cluster is defined by a flat list of usernames and groups. A client
is a user of the cluster if and only if her username is listed in the flat list or one of
her groups is explicitly listed in the flat list. Nested groups are not supported.
>     2. The flat list is stored in a conf file and pushed to every cluster node so that
services can access them.
>     3. Services will monitor the modification of the conf file periodically (5 mins interval
by default) and reload the list if needed.
>     4. Checking against the flat list is done as early as possible and before any other
authorization checking. Both HDFS and M/R clusters will implement this feature.
>     5. This feature can be switched off and is off by default.
> I'm aware of interests in pulling user data from LDAP. For this JIRA, I suggest we implement
it using a conf file. Additional data sources may be supported via new JIRA's.

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