docs/root/configuration/upstream/health_checkers/redis.rst
.. _config_health_checkers_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 <envoy_v3_api_field_extensions.health_checkers.redis.v3.Redis.key> to any value and waiting
for traffic to drain.
An example setting for :ref:custom_health_check <envoy_v3_api_msg_config.core.v3.HealthCheck.CustomHealthCheck> 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.extensions.health_checkers.redis.v3.Redis key: foo
v3 API reference <envoy_v3_api_msg_config.core.v3.HealthCheck.CustomHealthCheck>The redis health checker can also be configured with AWS IAM Authentication, in the same way as the redis_proxy filter. see
:ref:AWS IAM Authentication <config_network_filters_redis_proxy_aws_iam> for more information.
The Redis health checker emits some statistics in the health_check.redis. namespace.
.. csv-table:: :header: Name, Description :widths: 1, 2
exists_failure, Total number of health check failures caused by EXISTS check failure.