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https://issues.apache.org/jira/browse/ZOOKEEPER-4282?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17397435#comment-17397435
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Mohammad Arshad commented on ZOOKEEPER-4282:
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[~ztzg] Thanks for sharing the scary story. Its supporting the need to protect
the internal ZooKeeper data structure from outside modification.
bq. I would suggest opening another ticket, and creating PRs preventing the
server crash for 3.5 and 3.6. WDYT? Should I take care of it?
I think preventing server crash after allowing wrong data to be set in quota
znode will work but it is better to prevent the cause itself. Should not allow
to set wrong data in quota znodes.
But the changes I am proposing will be big and may not go in branch-3.6 and
branch-3.5. So I am OK with any work around solution on those branches. If you
have interest please go ahead.(y)
> Redesign quota feature
> ----------------------
>
> Key: ZOOKEEPER-4282
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-4282
> Project: ZooKeeper
> Issue Type: New Feature
> Components: quota
> Reporter: Mohammad Arshad
> Assignee: Mohammad Arshad
> Priority: Major
> Fix For: 3.8.0
>
>
> *Quota Use Case:*
> Generally in a big data solution deployment multiple services (hdfs, yarn,
> hbase etc.) use single Zookeeper cluster. So it is very important to ensure
> fare usage by all services. Sometime services unintentionally, mainly because
> of faulty behavior, create many znodes and impact the overall reliability of
> the ZooKeeper service. To ensure the faire usage quota feature is required.
> But this is the only use case there are many other use cases for quota
> feature.
> *Current Problems:*
> # Currently, user can set quota by updating znode
> “/zookeeper/quota/nodepath”, or using setquota/delquota in CLI command.
> This makes the quota setting infective
> Currently any user can set/delete quota, which is not proper, it should be
> admin operation
> # User is allowed to modify zookeeper system paths like /zookeeper/quota.
> These are internal to zookeeper should not be allowed to modify.
> # Generally services create single top level znode in Zookeeper like /hbase
> and create all required znode under it.
> It is better if it is configurable who can create top level znodes to
> controll ZooKeeper usage.
> # After ZOOKEEPER-231, there two kinds quota enforcement limits 1. Hard limit
> 2. Soft limit.
> I think there should be only limit. When enforce quota is enabled that limits
> becomes the hard limit otherwise it is soft limit same as old feature, just
> logs warnings.
> *Proposed Solution*
> # Add setQuota and deleteQuota admin APIs. Add listQuota normal user API
> Modify quota cli commands to use these APIs instead of directory modifying
> ZooKeeper system path /zookeeper/quota/
> # Protect ZooKeeper system paths from outside modification. System should
> only be readable from outside
> # Expose configuration to set ACL for root system znode.
> After this, at the time of ZooKeeper service deployment administrator can
> create top level znode for a service and set quota. This way we can control
> overall ZooKeeper usage
> # Revert some of the changes in ZOOKEEPER-231 and move to single quota limit
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