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https://issues.apache.org/jira/browse/ACCUMULO-3513?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14294563#comment-14294563
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Christopher Tubbs commented on ACCUMULO-3513:
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>From Accumulo's perspective, it would just mean that we "trust" the MapReduce
>layer to do the check... whether that means we choose to lock down access to
>the MapReduce layer, or whatever mechanism involved in the MapReduce layer to
>authenticate clients is properly propagated to Accumulo.
It doesn't prevent unwanted impersonation... it simply assigns trust to the
MapReduce system to do that. At some point, I think that's the best we can get.
We cannot get direct access to the client's credentials, so we must trust
another party (in this case, the MapReduce servers).
We could require that the clients authenticate to Accumulo to generate a shared
secret (really, though, they just need to authenticate to the Authenticator
implementation backing Accumulo). This is analogous to the HDFS delegation
token. The client can then give this shared secret to the MapReduce layer to
use when talking to Accumulo, to ensure that the client did actually hand that
secret to the MapReduce layer, requesting it to do work on its behalf. However,
we still need to designate the MapReduce layer as trustable in some way...
because this layer could reuse one client's credentials to perform an
unauthorized task and give the results to a different user. The whitelist
mechanism gives us some assurance that we've vetted that layer to not do those
sorts of things.
If we already have to designate trust to that intermediate layer, I don't see a
lot of added value with the complexity of the delegation token mechanism to
prove that it is, in fact, doing work on behalf of a particular client.
> Ensure MapReduce functionality with Kerberos enabled
> ----------------------------------------------------
>
> Key: ACCUMULO-3513
> URL: https://issues.apache.org/jira/browse/ACCUMULO-3513
> Project: Accumulo
> Issue Type: Bug
> Components: client
> Reporter: Josh Elser
> Assignee: Josh Elser
> Priority: Blocker
> Fix For: 1.7.0
>
>
> I talked to [~devaraj] today about MapReduce support running on secure Hadoop
> to help get a picture about what extra might be needed to make this work.
> Generally, in Hadoop and HBase, the client must have valid credentials to
> submit a job, then the notion of delegation tokens is used by for further
> communication since the servers do not have access to the client's sensitive
> information. A centralized service manages creation of a delegation token
> which is a record which contains certain information (such as the submitting
> user name) necessary to securely identify the holder of the delegation token.
> The general idea is that we would need to build support into the master to
> manage delegation tokens to node managers to acquire and use to run jobs.
> Hadoop and HBase both contain code which implements this general idea, but we
> will need to apply them Accumulo and verify that it is M/R jobs still work on
> a kerberized environment.
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