[ https://issues.apache.org/jira/browse/HDFS-2949?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Rushabh S Shah updated HDFS-2949: --------------------------------- Status: Patch Available (was: Open) Added a check to see whether any other namenode is active or not. If not active then only transition to Active will go through otherwise not. > HA: Add check to active state transition to prevent operator-induced split > brain > -------------------------------------------------------------------------------- > > Key: HDFS-2949 > URL: https://issues.apache.org/jira/browse/HDFS-2949 > Project: Hadoop HDFS > Issue Type: Improvement > Components: ha, namenode > Affects Versions: 0.24.0 > Reporter: Todd Lipcon > Assignee: Rushabh S Shah > Attachments: HDFS-2949.patch > > > Currently, if the administrator mistakenly calls "-transitionToActive" on one > NN while the other one is still active, all hell will break loose. We can add > a simple check by having the NN make a getServiceState() RPC to its peer with > a short (~1 second?) timeout. If the RPC succeeds and indicates the other > node is active, it should refuse to enter active mode. If the RPC fails or > indicates standby, it can proceed. > This is just meant as a preventative safety check - we still expect users to > use the "-failover" command which has other checks plus fencing built in. -- This message was sent by Atlassian JIRA (v6.2#6252)