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Daryn Sharp commented on MAPREDUCE-3825:
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I should clarify how I implemented #1. Conceptually it does exactly what is
proposed.
* {{FileSystem#getDelegationTokens(renewer)}} unconditionally acquires all
tokens
* {{FileSystem#getDelegationTokens(renewer, creds)}} acquires only the tokens
that are missing from the creds. I would rather have added them to the creds
and returned just the new tokens. The idea was previously turned down, so I
was striving for compatibility with existing api. Note: existing impl causes
token cache to log it acquired the same token multiple times when it really
hasn't. The method should probably add new tokens to the creds, and return
only the new tokens instead of the full set.
* {{FileSystem#getDelegationTokens(renewer, creds)}} gets a unique list of leaf
filesystems and then gets their tokens
* {{FileSystems#getEmbeddedFileSystems()}} is implemented w/o the word embedded
and returns filesystems. Returning a list of URIs isn't desirable since it
forces a {{FileSystem.get}} which may create a new fs instance if the cache is
off, or creates unnecessary overhead if the cache is on. Both normal
filesystems and viewfs already have instantiations of the filesystems so I
thought it makes sense to return them.
bq. At end call getDelegationTokens(renewer) for each of non-dulicate URIs;
getDelegationTokens will return only one token since it is guaranteed that the
calls are for the leaf file systems.
The patch does acquire tokens for only the unique set of leaf filesystems. If
{{getDelegationTokens}} is required to return only one token, then why not call
{{getDelegationToken}} which is the existing method implemented by filesystems?
I don't think we want all subclasses to override {{getDelegationTokens}} since
it will force them to copy-n-paste the default impl with a one line tweak.
Thoughts?
> Need generalized multi-token filesystem support
> -----------------------------------------------
>
> Key: MAPREDUCE-3825
> URL: https://issues.apache.org/jira/browse/MAPREDUCE-3825
> Project: Hadoop Map/Reduce
> Issue Type: Bug
> Components: security
> Affects Versions: 0.23.1, 0.24.0
> Reporter: Daryn Sharp
> Assignee: Daryn Sharp
>
> This is the counterpart to HADOOP-7967. The token cache currently tries to
> assume a filesystem's token service key. The assumption generally worked
> while there was a one to one mapping of filesystem to token. With the advent
> of multi-token filesystems like viewfs, the token cache will try to use a
> service key (ie. for viewfs) that will never exist (because it really gets
> the mounted fs tokens).
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