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  • Reopen client if an ZK::Exceptions::InterruptedSession occurs (#50, mauricio)
  • Insert the "root_znode" path before "master_redis_node_manager_lock" and expose via accessor (#52, jzaleski)


  • Bumped required dependency on ZK gem. ZK 1.7.4 fixes a critical bug with locking (see
  • Fix an issue where a failover would not occur if we couldn't check the role of a downed master


** NOTE: This version of redis_failover requires that you upgrade your clients and Node Managers at the same time.

  • redis_failover now supports distributed monitoring among the Node Managers! Previously, the Node Managers were only used as a means of redundancy in case a particular node manager crashed. Starting with version 1.0 of redis_failover, the Node Managers will all periodically report their health report/snapshots. The primary Node Manager will utilize a configurable "node strategy" to determine if a particular node is available or unavailable.
  • redis_failover now supports a configurable "failover strategy" that's consulted when performing a failover. Currently, a single strategy is provided that takes into account the average latency of the last health check to the redis server.
  • Improved handling of underlying ZK client connection in RedisFailover::NodeManager
  • Add support for passing in an existing ZK client instance to
  • Reduce unnecessary writes to ZK

  • Add support for Redis#client's location method. Fixes a compatibility issue with redis_failover and Sidekiq.

  • Stop repeated attempts to acquire exclusive lock in Node Manager (#36)


  • Stubbed Client#client to return itself, fixes a fork reconnect bug with Resque (dbalatero)


  • Handle the node discovery error condition where the znode points to a master that is now a slave.


  • Introduce a safer master node discovery process for the Node Manager (#34)
  • Improved shutdown process for Node Manager


  • Preserve original master by reading from existing znode state.
  • Prevent Timeout::Error from bringing down the process (#32) (@eric)


  • Add lock assert for Node Manager.


  • Improved exception handling in NodeWatcher.


  • Improve nested exception handling.
  • Fix manual failover support when znode does not exist first.
  • Various fixes to work better with 1.8.7.


  • Make Node Manager's lock path vary with its main znode. (Bira)
  • Node Manager's znode for holding current list of redis nodes is no longer ephemeral. This is unnecessary since the current master should only be changed by redis_failover.
  • Introduce :master_only option for RedisFailover::Client (disabled by default). This option configures the client to direct all read/write operations to the master.
  • Introduce :safe_mode option (enabled by default). This option configures the client to purge its redis clients when a ZK session expires or when the client hasn't recently heard from the node manager.
  • Introduce RedisFailover::Client#on_node_change callback notification for when the currently known list of master/slave redis nodes changes.
  • Added #current_master and #current_slaves to RedisFailover::Client. This is useful for programmatically doing things based on the current master/slaves.
  • redis_node_manager should start if no redis servers are available (#29)
  • Better handling of ZK session expirations in Node Manager.


  • Handle errors raised by redis 3.x client (tsilen)


  • Use a stack for handling nested blocks in RedisFailover::Client (inspired by connection_pool gem)
  • Fix an issue with #multi and Redis 3.x.


  • Support TTL operation (#24)


  • No longer buffer output (kyohsuke)
  • Update redis/zk gem versions to latest (rudionrails)


  • Lock-down gemspec to version 1.1.x of redis-namespace to play nicely with redis 2.2.x.
  • Fix RedisFailover::Client#manual_failover regression (oleriesenberg)


  • Lock-down gemspec to redis 2.2.x in light of upcoming redis 3.x release. Once sufficient testing has been done with the 3.x release, I will relax the constraint in the gemspec.
  • Add environment-scoped configuration file support (oleriesenberg)


  • Added a way to gracefully shutdown/reconnect a RedisFailover::Client. (#13)
  • Upgraded to latest ZK version that supports forking.
  • Handle case where the same RedisFailover::Client is referenced by a #multi block (#14)


  • Fix method signature for RedisFailover::Client#respond_to_missing? (#12)


  • Added YARD documentation.
  • Improve ZooKeeper client connection management.
  • Upgrade to latest ZK gem stable release.


  • Added manual failover support (can be initiated via RedisFailover::Client#manual_failover)
  • Misc. cleanup


  • When new master promotion occurs, make existing slaves point to new candidate before promoting new master.
  • Add support for specifying command-line options in a config.yml file for Node Manager.
  • Upgrade to 0.9 version of ZK client and cleanup ZK connection error handling.


  • Add support for running multiple Node Manager processes for added redundancy (#4)
  • Add support for specifying a redis database in RedisFailover::Client (#5)
  • Improved Node Manager command-line option parsing


  • No longer use problematic ZK#reopen.


  • Handle more ZK exceptions as candidates for reconnecting the client on error.
  • Add safety check to actively purge redis clients if a RedisFailover::Client hasn't heard from the Node Manager in a certain time window.


  • Always try to create path before setting current state in Node Manager.
  • More explicit rescuing of exceptions.


  • More logging around exceptions
  • Handle re-watching on client session expirations / disconnections
  • Use an ephemeral node for the list of redis servers


  • redis_failover is now built on top of ZooKeeper! This means redis_failover enjoys all of the reliability, redundancy, and data consistency offered by ZooKeeper. The old fragile HTTP-based approach has been removed and will no longer be supported in favor of ZooKeeper. This does mean that in order to use redis_failover, you must have ZooKeeper installed and running. Please see the README for steps on how to do this if you don't already have ZooKeeper running in your production environment.


  • No longer force newly available slaves to master if already slaves of that master
  • Honor a node's slave-serve-stale-data configuration option; do not mark a sync-with-master-in-progress slave as available if its slave-serve-stale-data is disabled
  • Change reachable/unreachable wording to available/unavailable
  • Added node reconciliation, i.e. if a node comes back up, make sure that the node manager and the node agree on current role
  • More efficient use of redis client connections
  • Raise proper error for unsupported operations (i.e., those that don't make sense for a failover client)
  • Properly handle any hanging node operations in the failover server


  • Integrated travis-ci
  • Added background monitor to client for proactively detecting changes to current set of redis nodes


  • Added retry support for contacting failover server from client
  • Client now verifies proper master/slave role before attempting operation
  • General edge case cleanup for NodeManager


  • Fix option parser require


  • First release