TestFailover - Amazon ElastiCache
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Represents the input of a TestFailover operation which test automatic failover on a specified node group (called shard in the console) in a replication group (called cluster in the console).

This API is designed for testing the behavior of your application in case of ElastiCache failover. It is not designed to be an operational tool for initiating a failover to overcome a problem you may have with the cluster. Moreover, in certain conditions such as large-scale operational events, Amazon may block this API.

Note the following
  • A customer can use this operation to test automatic failover on up to 5 shards (called node groups in the ElastiCache API and Amazon CLI) in any rolling 24-hour period.

  • If calling this operation on shards in different clusters (called replication groups in the API and CLI), the calls can be made concurrently.

  • If calling this operation multiple times on different shards in the same Redis (cluster mode enabled) replication group, the first node replacement must complete before a subsequent call can be made.

  • To determine whether the node replacement is complete you can check Events using the Amazon ElastiCache console, the Amazon CLI, or the ElastiCache API. Look for the following automatic failover related events, listed here in order of occurrance:

    1. Replication group message: Test Failover API called for node group <node-group-id>

    2. Cache cluster message: Failover from primary node <primary-node-id> to replica node <node-id> completed

    3. Replication group message: Failover from primary node <primary-node-id> to replica node <node-id> completed

    4. Cache cluster message: Recovering cache nodes <node-id>

    5. Cache cluster message: Finished recovery for cache nodes <node-id>

    For more information see:

Also see, Testing Multi-AZ in the ElastiCache User Guide.

Request Parameters

For information about the parameters that are common to all actions, see Common Parameters.


The name of the node group (called shard in the console) in this replication group on which automatic failover is to be tested. You may test automatic failover on up to 5 node groups in any rolling 24-hour period.

Type: String

Length Constraints: Minimum length of 1. Maximum length of 4.

Pattern: \d+

Required: Yes


The name of the replication group (console: cluster) whose automatic failover is being tested by this operation.

Type: String

Required: Yes

Response Elements

The following element is returned by the service.


Contains all of the attributes of a specific Redis replication group.

Type: ReplicationGroup object


For information about the errors that are common to all actions, see Common Errors.


The customer has exceeded the allowed rate of API calls.

HTTP Status Code: 400


The requested cluster is not in the available state.

HTTP Status Code: 400


The KMS key supplied is not valid.

HTTP Status Code: 400


Two or more incompatible parameters were specified.

HTTP Status Code: 400


The value for a parameter is invalid.

HTTP Status Code: 400


The requested replication group is not in the available state.

HTTP Status Code: 400


The node group specified by the NodeGroupId parameter could not be found. Please verify that the node group exists and that you spelled the NodeGroupId value correctly.

HTTP Status Code: 404


The specified replication group does not exist.

HTTP Status Code: 404


The TestFailover action is not available.

HTTP Status Code: 400



The following example tests automatic failover on the Redis (cluster mode disabled) replication group (console: cluster) redis00. Since there is only one node group in Redis (cluster mode disabled) clusters, the NodeGroupId will always be <cluster-name>-0001.

Sample Request

https://elasticache.us-west-2.amazonaws.com/ ?Action=TestFailover &NodeGroupId=redis00-0001 &ReplicationGroupId=redis00 &Version=2015-02-02 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20170418T192317Z &X-Amz-Credential=<credential>

See Also

For more information about using this API in one of the language-specific Amazon SDKs, see the following: