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https://issues.apache.org/jira/browse/MAPREDUCE-3825?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13209875#comment-13209875
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Sanjay Radia commented on MAPREDUCE-3825:
-----------------------------------------
Solution 4
* Has some elements from solutions 1, 2 and 3
* Distinguishes between leaf FSs and FSs that embed other FSs
** getCanonicaServiceName() and getDelegationToken() both return null for
embedded FSs - don't like this but seems unavoidable.
* FileSystem#getChidrenFSs() - can be used to get embedded FSs - note it only
returns first level of children - this is more general and can have other uses
down the road.
* addDelegationTokens(renewer, credentials) has a default impl that will work
for all embedded FSs
** Perhaps this should be in FileUtil rather than FileSystem.
{code}
URI[] FileSystem#getChidrenFSs() { // return first level of children
return emptyList; // default - leaf file system return null
}
URI[] ViewFileSystem#getChidrenFileSystems() {
return the mount points but don't recurse through.
}
String FileSystem#getCanonicaServiceName - no change except ViewFileSystem
return null;
Token getDelegationToken() - no change except ViewFileSystem returns null
// Credentials is a map<serviceName, Token>
void FileSystem#addDelegationTokens(renewer, credentials) {
// this is new method - the old getDTs() is not needed.
// Provide a default impl here - viewfs does not override it.
- Walk the tree using getChildredFSs and collect all the leafs,
- if a fs return null then you know it is leaf.
- eliminate dups
- add missing tokens
}
// A Useful Utility - so that the TokenCache in MR can be easily implemented
FileUtil:GetTokens(renewer, path[] ps, credentials) {
foreach (p in ps) {
GetFileSystem(p).addDelegationTokens(renwer, credentials);
return;
}
{code}
> MR should not be getting duplicate tokens for a MR Job.
> -------------------------------------------------------
>
> 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
> Attachments: MAPREDUCE-3825.patch, TokenCache.pdf
>
>
> This is the counterpart to HADOOP-7967.
> MR gets tokens for all input, output and the default filesystem when a MR job
> is submitted.
> The APIs in FileSystem make it challenging to avoid duplicate tokens when
> there are file systems that have embedded
> filesystems.
> Here is the original description that Daryn wrote:
> 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).
> The descriop
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