[HADOOP-12474] MiniKMS should use random ports for Jetty server by default

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.8.0, 3.0.0-alpha1
• Target Version/s: 2.8.0
• Hadoop Flags: Reviewed
• Assignee: Mingliang Liu
• Reporter: Mingliang Liu
• Created: 13/Oct/15 06:11
• Updated: 30/Aug/16 01:22
• Resolved: 13/Oct/15 20:10

Description

In MiniKMS, there is potential data race when create jetty server in createJettyServer. It looks like the code searches for a free port and then starts jetty, but maybe there's enough of a race condition between port location and jetty.start to cause intermittent failures.

      ServerSocket ss = new ServerSocket((inPort < 0) ? 0 : inPort, 50, localhost);
      int port = ss.getLocalPort();
      Server server = new Server(0);
      if (!ssl) {
        server.getConnectors()[0].setHost(host);
        server.getConnectors()[0].setPort(port);
      } else {
        ...
        c.setPort(port);

We've seen test failures saying java.net.BindException: Address already in use, e.g. https://builds.apache.org/job/PreCommit-HDFS-Build/12942/testReport/

As in HADOOP-12417, we should always bind port 0 which gives us an ephemeral port, instead of searching a free port before starting jetty.