JdbcDriverZookeeperTest fails on CI

[eolivelli]

I feel this was the real cause of #494 ZooKeeper server sometimes cannot start because it wants to launch embedded Jetty server

org.apache.zookeeper.server.admin.AdminServer$AdminServerException: Problem starting AdminServer on address 0.0.0.0, port 8080 and command URL /commands
	at org.apache.zookeeper.server.admin.JettyAdminServer.start(JettyAdminServer.java:107)
	at org.apache.zookeeper.server.ZooKeeperServerMain.runFromConfig(ZooKeeperServerMain.java:138)
	at org.apache.curator.test.TestingZooKeeperMain.runFromConfig(TestingZooKeeperMain.java:93)
	at org.apache.curator.test.TestingZooKeeperServer$1.run(TestingZooKeeperServer.java:148)
	at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.net.BindException: Address already in use
	at java.base/sun.nio.ch.Net.bind0(Native Method)
	at java.base/sun.nio.ch.Net.bind(Net.java:455)
	at java.base/sun.nio.ch.Net.bind(Net.java:447)
	at java.base/sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:227)
	at java.base/sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:80)
	at org.eclipse.jetty.server.ServerConnector.open(ServerConnector.java:298)
	at org.eclipse.jetty.server.AbstractNetworkConnector.doStart(AbstractNetworkConnector.java:80)
	at org.eclipse.jetty.server.ServerConnector.doStart(ServerConnector.java:236)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
	at org.eclipse.jetty.server.Server.doStart(Server.java:431)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:68)
	at org.apache.zookeeper.server.admin.JettyAdminServer.start(JettyAdminServer.java:103)
	... 4 more

[eolivelli]

hey @TisonKun I think I found the root cause of the issue #494

[tisonkun]

It sounds like a port conflict/occupied issue? possibly we bind on "0" and let the OS chooses an idle port