[HDFS-2731] HA: Autopopulate standby name dirs if they're empty

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0-alpha
• Fix Version/s: 2.0.0-alpha
• Component/s: ha
• Hadoop Flags: Reviewed

Release Note

The HA NameNode may now be started with the "-bootstrapStandby" flag. This causes it to copy the namespace information and most recent checkpoint from its HA pair, and save it to local storage, allowing an HA setup to be bootstrapped without use of rsync or external tools.

• Assignee: Todd Lipcon
• Reporter: Aaron Myers
• Created: 30/Dec/11 00:32
• Updated: 28/Sep/15 20:58
• Resolved: 12/Mar/12 19:45

Description

To setup a SBN we currently format the primary then manually copy the name dirs to the SBN. The SBN should do this automatically. Specifically, on NN startup, if HA with a shared edits dir is configured and populated, if the SBN has empty name dirs it should downloads the image and log from the primary (as an optimization it could copy the logs from the shared dir). If the other NN is still in standby then it should fail to start as it does currently.

Issue Links

• breaks: HDFS-3093 TestAllowFormat is trying to be interactive
• is blocked by: HADOOP-8141 Add method to init krb5 cipher suites
• relates to: HDFS-3079 Document -bootstrapStandby flag for deploying HA