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https://issues.apache.org/jira/browse/HADOOP-12076?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14580694#comment-14580694
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Sean Busbey commented on HADOOP-12076:
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{quote}
bq. Since AbstractJavaKeyStore isn't thread safe, do we know what happens if
multiple instances are pointing at the same jks file?
I'm not entirely sure of the usecase that you have in mind. There are
read/write locks in this class for providing thread safety. Perhaps there are
state issues not covered properly? If so, we should file separate jiras for
them.
{quote}
The {{getCache}} method means we have no control over how the HashMap backing
the cache is accessed. A follow-on jira is fine by me.
{quote}
bq. Presuming the above works, how do we reconcile changes that happen to the
underlying jks against the cache?
I think this is largely answered by in the previous question. I guess if
passwords are added to the store that they will be picked up without any need
for restart or new instances - due to them not being cached. If you used the
CLI and deleted an SSL password it would still be returned by the cache until
restart or new instances (again, Configuration.getPassword isn't a problem
there). If you change the existing password to a keystore then it will probably
continue to work until you restart and try to load the certs again. In which
case, if the new password matches the keystore it will work otherwise it won't.
{quote}
Since JavaKeyStoreProvider has already been in released versions, any caching
done here has to maintain the same behavior as found in 2.6.0 and 2.7.0 (or the
change needs to be marked incompatible and release noted).
{quote}
Interestingly, based on trying to change the test to ensure that non-cached
items are not returned when the underlying store is deleted, it seems that the
in-memory keystore instance itself serves as a cache. I have found that when a
credentialEntry is added to the in-memory it is always returned even if the
underlying jks is deleted and the value wasn't queried prior. I even persisted
the store with a flush() and instantiated a new provider. The act of loading
the keystore reads everything into memory - so, even when I remove the file it
is still returned by the getCredentialEntry since it is in the in-memory
keystore. It doesn't even need to be in the cache.
Not sure what value the additional cache adds here. There may be some overhead
to pulling it out of the keystore and the KeyEntry but not sure.
{quote}
Does the loaded KeyStore recognize (non-deleted) changes to the underlying file
after it's been loaded? It's possible that while the file still exists the
keystore could use filesystem stat calls to find out if it has changed and
update its cache as appropriate.
Sounds like we should change the test to be backed by MiniDFS instead of a
local file uri? That should give us a better idea of what's happening in
ACCUMULO-3890.
> Incomplete Cache Mechanism in CredentialProvider API
> ----------------------------------------------------
>
> Key: HADOOP-12076
> URL: https://issues.apache.org/jira/browse/HADOOP-12076
> Project: Hadoop Common
> Issue Type: Bug
> Components: security
> Reporter: Larry McCay
> Assignee: Larry McCay
> Attachments: HADOOP-12076-001.patch
>
>
> The AbstractJavaKeyStoreProvider class in the CredentialProvider API has a
> cache member variable and interrogation of it during access but does not
> populate it.
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