Affects Version/s: 3.4.8, 3.4.9, 3.4.10, 3.5.0, 3.5.1, 3.5.2, 3.4.11
Fix Version/s: 3.4.11
The QuorumPeer$QuorumServer.recreateSocketAddress() is used to resolved the hostname to a new IP address(InetAddress) when any exception happens to the socket. It will be very useful when a hostname can be resolved to more than one IP address.
But the problem is Java API InetAddress.getByName(String hostname) will always return the first IP address when the hostname can be resolved to more than one IP address, and the first IP address may be unreachable forever. For example, if a machine has two network interfaces: eth0, eth1, say eth0 has ip1, eth1 has ip2, the relationship between hostname and the IP addresses is set in /etc/hosts. When I "close" the eth0 by command "ifdown eth0", the InetAddress.getByName(String hostname) will still return ip1, which is unreachable forever.
So I think it will be better to check the IP address by InetAddress.isReachable(long) and choose the reachable IP address.
I have modified the ZooKeeper source code, and test the new code in my own environment, and it can work very well when I turn down some network interfaces using "ifdown" command.
The original code is:
After my modification: