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Amazon ElastiCache
ElastiCache for Memcached User Guide (API Version 2015-02-02)

Modifying an ElastiCache Cluster

In addition to adding or removing nodes from a cluster, there can be times where you need to make other changes to an existing cluster, such as, adding a security group, changing the maintenance window or a parameter group.

We recommend that you have your maintenance window fall at the time of lowest usage. Thus it might need modification from time to time.

When you make a change to a cluster's parameters, either by changing the cluster's parameter group or by changing a parameter value in the cluster's parameter group, the changes are applied to the cluster either immediately or after the cluster is restarted. To determine when a particular parameter change is applied, see the Changes Take Effect column in the tables for Memcached Specific Parameters and . For information on rebooting a cluster, see Rebooting a Cluster.

Using the AWS Management Console

To modify a cluster (console)

  1. Sign in to the AWS Management Console and open the ElastiCache console at https://console.aws.amazon.com/elasticache/.

  2. From the list in the upper-right corner, choose the AWS Region where the cluster you want to modify is located.

  3. In the navigation pane, choose the engine running on the cluster you want to modify.

    A list of the chosen engine's clusters appears.

  4. In the list of clusters, choose the name of the cluster you want to modify.

  5. Choose Modify.

    The Modify Cluster window appears.

  6. In the Modify Cluster window, make the modification(s) you want.

    Important

    You can upgrade to newer engine versions (see Upgrading Engine Versions), but you cannot downgrade to older engine versions except by deleting the existing cluster and creating it anew.

    The Apply Immediately box applies only to modifications in node type and engine version. If you want to apply any of these changes immediately, choose the Apply Immediately check box. If this box is not chosen, engine version and node type modifications will be applied during the next maintenance window. Other modifications, such as changing the maintenance window, are applied immediately.

  7. Choose Modify.

Using the AWS CLI

You can modify an existing cluster using the AWS CLI modify-cache-cluster operation. To modify a cluster's configuration value, specify the cluster's ID, the parameter to change and the parameter's new value. The following example changes the maintenance window for a cluster named my-cluster and applies the change immediately.

Important

You can upgrade to newer engine versions (see Upgrading Engine Versions), but you cannot downgrade to older engine versions except by deleting the existing cluster and creating it anew.

For Linux, macOS, or Unix:

aws elasticache modify-cache-cluster \ --cache-cluster-id my-cluster \ --preferred-maintenance-window sun:23:00-mon:02:00

For Windows:

aws elasticache modify-cache-cluster ^ --cache-cluster-id my-cluster ^ --preferred-maintenance-window sun:23:00-mon:02:00

The --apply-immediately parameter applies only to modifications in node type, engine version, and changing the number of nodes in a cluster. If you want to apply any of these changes immediately, use the --apply-immediately parameter. If you prefer postponing these changes to your next maintenance window, use the --no-apply-immediately parameter. Other modifications, such as changing the maintenance window, are applied immediately.

For more information, see the AWS CLI for ElastiCache topic modify-cache-cluster.

Using the ElastiCache API

You can modify an existing cluster using the ElastiCache API ModifyCacheCluster operation. To modify a cluster's configuration value, specify the cluster's ID, the parameter to change and the parameter's new value. The following example changes the maintenance window for a cluster named my-cluster and applies the change immediately.

Important

You can upgrade to newer engine versions (see Upgrading Engine Versions), but you cannot downgrade to older engine versions except by deleting the existing cluster and creating it anew.

Line breaks are added for ease of reading.

https://elasticache.us-west-2.amazonaws.com/ ?Action=ModifyCacheCluster &CacheClusterId=my-cluster &PreferredMaintenanceWindow=sun:23:00-mon:02:00 &SignatureVersion=4 &SignatureMethod=HmacSHA256 &Timestamp=20150901T220302Z &X-Amz-Algorithm=AWS4-HMAC-SHA256 &X-Amz-Date=20150202T220302Z &X-Amz-SignedHeaders=Host &X-Amz-Expires=20150901T220302Z &X-Amz-Credential=<credential> &X-Amz-Signature=<signature>

The ApplyImmediately parameter applies only to modifications in node type, engine version, and changing the number of nodes in a cluster. If you want to apply any of these changes immediately, set the ApplyImmediately parameter to true. If you prefer postponing these changes to your next maintenance window, set the ApplyImmediately parameter to false. Other modifications, such as changing the maintenance window, are applied immediately.

For more information, see the ElastiCache API reference topic ModifyCacheCluster.