Rebooting nodes - Amazon ElastiCache
Rebooting Redis OSS nodes (cluster mode disabled only)Rebooting a cluster for Memcached

Rebooting nodes

Some changes require that a Redis OSS or Memcached cluster be rebooted for the changes to be applied. For example, for some parameters, changing the parameter value in a parameter group is only applied after a reboot.

Rebooting Redis OSS nodes (cluster mode disabled only)

For Valkey or Redis OSS (cluster mode disabled) clusters, the parameters in parameter groups that are applied only after rebooting are:

  • activerehashing

  • databases

Redis nodes can only be updated through the ElastiCache console. You can only reboot a single node at a time. To reboot multiple nodes, you must repeat the process for each node.

Valkey or Redis OSS (Cluster Mode Enabled) parameter changes

If you make changes to the following parameters on a Valkey or Redis OSS (cluster mode enabled) cluster, follow the ensuing steps.

  • activerehashing

  • databases

  1. Create a manual backup of your cluster. See Taking manual backups.

  2. Delete the Valkey or Redis OSS (cluster mode enabled) cluster. See Deleting a cluster in ElastiCache.

  3. Restore the cluster using the altered parameter group and backup to seed the new cluster. See Restoring from a backup into a new cache.

Changes to other parameters do not require this.

You can reboot a node using the ElastiCache console.

To reboot a node (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 that applies.

  3. In the left navigation pane, choose Redis OSS.

    A list of clusters running Redis OSS appears.

  4. Choose the cluster under Cluster Name.

  5. Under Node name, choose the radio button next to the node you want to reboot.

  6. Choose Actions, and then choose Reboot node.

To reboot multiple nodes, repeat steps 2 through 5 for each node that you want to reboot. You do not need to wait for one node to finish rebooting to reboot another.

Rebooting a cluster for Memcached

When you reboot a Memcached cluster, the cluster flushes all its data and restarts its engine. During this process you cannot access the cluster. Because the cluster flushed all its data, when the cluster is available again, you are starting with an empty cluster.

You are able to reboot a cluster using the ElastiCache console, the AWS CLI, or the ElastiCache API. Whether you use the ElastiCache console, the AWS CLI or the ElastiCache API, you can only initiate rebooting a single cluster. To reboot multiple clusters you must iterate on the process or operation.

You can reboot a cluster using the ElastiCache console.

To reboot 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 you are interested in.

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

    A list of clusters running the chosen engine appears.

  4. Choose the cluster to reboot by choosing on the box to the left of the cluster's name.

    The Reboot button becomes active.

    If you choose more than one cluster, the Reboot button isn't active.

  5. Choose Reboot.

    The reboot cluster confirmation screen appears.

  6. To reboot the cluster, choose Reboot. The status of the cluster changes to rebooting cluster nodes.

    To not reboot the cluster, choose Cancel.

To reboot multiple clusters, repeat steps 2 through 5 for each cluster that you want to reboot. You do not need to wait for one cluster to finish rebooting to reboot another.

To reboot a specific node, select the node and then choose Reboot.

To reboot a cluster (AWS CLI), use the reboot-cache-cluster CLI operation.

To reboot specific nodes in the cluster, use the --cache-node-ids-to-reboot to list the specific clusters to reboot. The following command reboots the nodes 0001, 0002, and 0004 of my-cluster.

For Linux, macOS, or Unix:

aws elasticache reboot-cache-cluster \
    --cache-cluster-id my-cluster \
    --cache-node-ids-to-reboot 0001 0002 0004

For Windows:

aws elasticache reboot-cache-cluster ^
    --cache-cluster-id my-cluster ^
    --cache-node-ids-to-reboot 0001 0002 0004

To reboot all the nodes in the cluster, use the --cache-node-ids-to-reboot parameter and list all the cluster's node ids. For more information, see reboot-cache-cluster.

To reboot a cluster using the ElastiCache API, use the RebootCacheCluster action.

To reboot specific nodes in the cluster, use the CacheNodeIdsToReboot to list the specific clusters to reboot. The following command reboots the nodes 0001, 0002, and 0004 of my-cluster.

https://elasticache.us-west-2.amazonaws.com/
   ?Action=RebootCacheCluster
   &CacheClusterId=my-cluster
   &CacheNodeIdsToReboot.member.1=0001
   &CacheNodeIdsToReboot.member.2=0002
   &CacheNodeIdsToReboot.member.3=0004
   &Version=2015-02-02
   &SignatureVersion=4
   &SignatureMethod=HmacSHA256
   &Timestamp=20150202T192317Z
   &X-Amz-Credential=<credential>

To reboot all the nodes in the cluster, use the CacheNodeIdsToReboot parameter and list all the cluster's node ids. For more information, see RebootCacheCluster.