[HDFS-15625] Namenode trashEmptier should not init ViewFs on startup

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.4.0
• Fix Version/s: 3.4.0
• Component/s: namenode, viewfs
• Labels: pull-request-available
• Hadoop Flags: Reviewed
• Assignee: Uma Maheswara Rao G
• Reporter: Uma Maheswara Rao G
• Created: 10/Oct/20 06:39
• Updated: 12/Oct/20 21:24
• Resolved: 12/Oct/20 21:24

Description

Currently on NN startup, Namenode starts trash emptier.
As part of HDFS-15450 we already fixed it by setting fs.hdfs.impl config in NN.
But as part of other JIRAs we seem to be reverted that change.

If I remember correctly, the issue in HDFS-15450 was about NN can't init ViewFsOverloadScheme because, NN always sets it's RPC address in fs.defaultFS. So, in HA case, user configured uri would always be a logical uri. So, NN could not start it as it can't init because it can't find any mount points with that changed fs.defaultFS authority. However that issues sorted out as for HDFS we recommend to use ViewHDFS and it will auto set a fallback mountpoint if no mount points configured.

However, we still need that changes needed back as initing ViewHDFS/ViewFSOverloadScheme would be costly when it has more mount points. Initing this mount based fs in trashEmptier is unnecessary.

With this JIRA I will just bring back similar functionality back.

Issue Links

• links to: GitHub Pull Request #2378