.. _config_health_checkers_redis: Redis ===== The Redis health checker is a custom health checker (with :code:`envoy.health_checkers.redis` as name) which checks Redis upstream hosts. It sends a Redis PING command and expect a PONG response. The upstream Redis server can respond with anything other than PONG to cause an immediate active health check failure. Optionally, Envoy can perform EXISTS on a user-specified key. If the key does not exist it is considered a passing health check. This allows the user to mark a Redis instance for maintenance by setting the specified :ref:`key ` to any value and waiting for traffic to drain. An example setting for :ref:`custom_health_check ` as a Redis health checker is shown below: .. code-block:: yaml custom_health_check: name: envoy.health_checkers.redis typed_config: "@type": type.googleapis.com/envoy.config.filter.network.redis_proxy.v2.RedisProxy key: foo * :ref:`v2 API reference `