jedis_failover - a failover solution for redis server clusters

This plugin is an implementation of the behaviour implemented originally at the redis_failover Ruby gem. It's main goal is to make your redis cluster to be highly available by automatically switching over the master status to a server that is available once the real master goes down or removing slaves that are not currently available so that clients don't try to access them.

The cluster status data lives in a ZooKeeper server or cluster. Each client process then becomes a NodeManager, that is, a watcher over the overall cluster status. Each NodeManager watches over the Redis cluster and validates the cluster status. They periodically send their current view of the system to ZooKeeper and one of them is selected as the cluster leader and he is the one that makes the final decision if a node is down or if there is a need to switch the master to a different server (and also makes the configuration changes on Redis as expected).

Usage

To use this project with just the defaults set, you can just create a pool using the pool builder as in:

JedisPool pool = new JedisPoolBuilder()
    .withFailoverConfiguration(
        "localhost:2838", // ZooKeeper cluster URL
        Arrays.asList(new HostConfiguration("localhost", 7000), new HostConfiguration("localhost", 7001))) // List of redis servers
    .build();

pool.withJedis(new JedisFunction() {
    @Override
    public void execute(final JedisActions jedis) throws Exception {
        jedis.ping();
    }
});

And you can just use the pool to access your Redis servers as expected. If you would like to be able to configure more stuff, you can, for now, check the source code and tests and see the other variables that can be changed on the configuration.

This library is compatible with the redis_failover as long as you don't the gem's node manager daemon. If you run only in client mode, the clients will correctly read the failover configuration and follow it.

Pending

• More configuration
• Fix leader election bug that prevents the library from working with the redis_failover gem node managers
• Allow for pools to be created without a node manager (client only mode, as in the Ruby gem)
• More tests
• Open HTTP port to allow for easy manual failover even for running processes