[jira] [Created] (ZOOKEEPER-2982) Re-try DNS hostname -> IP resolution

["Eron Wright (JIRA)" <ji...@apache.org>]

Eron Wright  created ZOOKEEPER-2982:
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             Summary: Re-try DNS hostname -> IP resolution
                 Key: ZOOKEEPER-2982
                 URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2982
             Project: ZooKeeper
          Issue Type: Bug
          Components: server
    Affects Versions: 3.5.3, 3.5.1, 3.5.0
            Reporter: Eron Wright 
             Fix For: 3.5.4


ZOOKEEPER-1506 fixed a DNS resolution issue in 3.4.  Some portions of the fix haven't yet been ported to 3.5.

To recap the outstanding problem in 3.5, if a given ZK server is started before all peer addresses are resolvable, that server may cache a negative lookup result and forever fail to resolve the address.    For example, deploying ZK 3.5 to Kubernetes using a StatefulSet plus a Service (headless) may fail because the DNS records are created lazily.

{code}
2018-02-18 09:11:22,583 [myid:0] - WARN  [QuorumPeer[myid=0](plain=/0:0:0:0:0:0:0:0:2181)(secure=disabled):Follower@95] - Exception when following the leader
java.net.UnknownHostException: zk-2.zk.default.svc.cluster.local
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:184)
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
        at java.net.Socket.connect(Socket.java:589)
        at org.apache.zookeeper.server.quorum.Learner.sockConnect(Learner.java:227)
        at org.apache.zookeeper.server.quorum.Learner.connectToLeader(Learner.java:256)
        at org.apache.zookeeper.server.quorum.Follower.followLeader(Follower.java:76)
        at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:1133)
{code}



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