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Aaron T. Myers commented on HADOOP-8163: ---------------------------------------- Thanks for addressing my comments, Todd. I think this patch looks a lot better. IllegalStateException is a good choice instead of AssertionError. A few nits follow. +1 once these are addressed: # Am I missing something, or are ensureBaseZNode and baseNodeExists only called by the tests? If so, we should probably relocate them, or at least mark them @VisibleForTesting if they can't be moved for some reason. # Maybe include the path of the ZNode in the log message "Writing record of this node as the most recent active..." # We're now using CamelCase for all ZNode names, but two comments still reference a dash-separated name. # I still think we should rename operationSuccess, etc. Feel free to punt to another JIRA. > Improve ActiveStandbyElector to provide hooks for fencing old active > -------------------------------------------------------------------- > > Key: HADOOP-8163 > URL: https://issues.apache.org/jira/browse/HADOOP-8163 > Project: Hadoop Common > Issue Type: Improvement > Components: ha > Affects Versions: 0.24.0, 0.23.3 > Reporter: Todd Lipcon > Assignee: Todd Lipcon > Attachments: hadoop-8163.txt, hadoop-8163.txt > > > When a new node becomes active in an HA setup, it may sometimes have to take > fencing actions against the node that was formerly active. This JIRA extends > the ActiveStandbyElector which adds an extra non-ephemeral node into the ZK > directory, which acts as a second copy of the active node's information. > Then, if the active loses its ZK session, the next active to be elected may > easily locate the unfenced node to take the appropriate actions. -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira