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Kihwal Lee commented on HADOOP-7472: ------------------------------------ Result of running test-patch on 0.20-security: [exec] -1 overall. [exec] [exec] +1 @author. The patch does not contain any @author tags. [exec] [exec] -1 tests included. The patch doesn't appear to include any new or modified tests. [exec] Please justify why no tests are needed for this patch. [exec] [exec] -1 javadoc. The javadoc tool appears to have generated 1 warning messages. [exec] [exec] +1 javac. The applied patch does not increase the total number of javac compiler warnings. [exec] [exec] +1 findbugs. The patch does not introduce any new Findbugs (version 1.3.9) warnings. [exec] > RPC client should deal with the IP address changes > -------------------------------------------------- > > Key: HADOOP-7472 > URL: https://issues.apache.org/jira/browse/HADOOP-7472 > Project: Hadoop Common > Issue Type: Improvement > Components: ipc > Affects Versions: 0.20.205.0 > Reporter: Kihwal Lee > Assignee: Kihwal Lee > Priority: Minor > Fix For: 0.20.205.0 > > Attachments: addr_change_dfs-1.patch.txt, addr_change_dfs.patch.txt > > > The current RPC client implementation and the client-side callers assume that > the hostname-address mappings of servers never change. The resolved address > is stored in an immutable InetSocketAddress object above/outside RPC, and the > reconnect logic in the RPC Connection implementation also trusts the resolved > address that was passed down. > If the NN suffers a failure that requires migration, it may be started on a > different node with a different IP address. In this case, even if the > name-address mapping is updated in DNS, the cluster is stuck trying old > address until the whole cluster is restarted. > The RPC client-side should detect this situation and exit or try to recover. > Updating ConnectionId within the Client implementation may get the system > work for the moment, there always is a risk of the cached address:port become > connectable again unintentionally. The real solution will be notifying upper > layer of the address change so that they can re-resolve and retry or > re-architecture the system as discussed in HDFS-34. > For 0.20 lines, some type of compromise may be acceptable. For example, raise > a custom exception for some well-defined high-impact upper layer to do > re-resolve/retry, while other will have to restart. For TRUNK, the HA work > will most likely determine what needs to be done. So this Jira won't cover > the solutions for TRUNK. -- This message is automatically generated by JIRA. For more information on JIRA, see: http://www.atlassian.com/software/jira