Managing service updates - Amazon ElastiCache for Redis

Managing service updates

ElastiCache service updates for self-designed clusters are released on a regular basis. If you have one or more qualifying self-designed clusters for those service updates, you receive notifications through email, SNS, the Personal Health Dashboard (PHD), and Amazon CloudWatch events when the updates are released. The updates are also displayed on the Service Updates page on the ElastiCache console. By using this dashboard, you can view all the service updates and their status for your ElastiCache fleet. Service updates for serverless caches are transparently applied and cannot be managed via Service Updates.

You control when to apply an update before an auto-update starts. We strongly recommend that you apply any updates of type security-update as soon as possible to ensure that your ElastiCache clusters are always up-to-date with current security patches.

The following sections explore these options in detail.

Applying the service updates

You can start applying the service updates to your fleet from the time that the updates have an available status. Service updates are cumulative. In other words, any updates that you haven't applied yet are included with your latest update.

If a service update has auto-update enabled, you can choose to not take any action when it becomes available. ElastiCache will schedule to apply the update during one of your clusters' upcoming maintenance windows after the Auto-update start date. You will receive related notifications for each stage of the update.

Note

You can apply only those service updates that have an available or scheduled status.

For more information about reviewing and applying any service-specific updates to applicable ElastiCache clusters, see Applying the service updates using the console.

When a new service update is available for one or more of your ElastiCache clusters, you can use the ElastiCache console, API, or AWS CLI to apply the update. The following sections explain the options that you can use to apply updates.

Applying the service updates using the console

To view the list of available service updates, along with other information, go to the Service Updates page in the console.

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

  2. On the navigation pane, choose Service Updates.

  3. Under Service updates you can view the following:

    • Service update name: The unique name of the service update

    • Update type: The type of the service update, which is one of security-update or engine-update

    • Update severity: The priority of applying the update:

      • critical: We recommend that you apply this update immediately (within 14 days or less).

      • important: We recommend that you apply this update as soon as your business flow allows (within 30 days or less).

      • medium: We recommend that you apply this update as soon as you can (within 60 days or less).

      • low: We recommend that you apply this update as soon as you can (within 90 days or less).

    • Engine version: If the update type is engine-update, the engine version that is being updated.

    • Release Date: When the update is released and available to apply on your clusters.

    • Recommended Apply By Date: ElastiCache guidance date to apply the updates by.

    • Status: The status of the update, which is one of the following:

      • available: The update is available for requisite clusters.

      • complete: The update has been applied.

      • cancelled: The update has been canceled and is no longer necessary.

      • expired: The update is no longer available to apply.

  4. Choose an individual update (not the button to its left) to view details of the service update.

    In the Cluster update status section, you can view a list of clusters where the service update has not been applied or has just been applied recently. For each cluster, you can view the following:

    • Cluster name: The name of the cluster

    • Nodes updated: The ratio of individual nodes within a specific cluster that were updated or remain available for the specific service update.

    • Update Type: The type of the service update, which is one of security-update or engine-update

    • Status: The status of the service update on the cluster, which is one of the following:

      • available: The update is available for the requisite cluster.

      • in-progress: The update is being applied to this cluster.

      • scheduled: The update date has been scheduled.

      • complete: The update has been successfully applied. Cluster with a complete status will be displayed for 7 days after its completion.

      If you chose any or all of the clusters with the available or scheduled status, and then chose Apply now, the update will start being applied on those clusters.

Applying the service updates using the AWS CLI

After you receive notification that service updates are available, you can inspect and apply them using the AWS CLI:

  • To retrieve a description of the service updates that are available, run the following command:

    aws elasticache describe-service-updates --service-update-status available

    For more information, see describe-service-updates.

  • To apply a service update on a list of clusters, run the following command:

    aws elasticache batch-apply-update-action --service-update ServiceUpdateNameToApply=sample-service-update --cluster-names cluster-1 cluster2

    For more information, see batch-apply-update-action.

Verifying you have the latest Service Update Applied using the AWS console

You can verify your ElastiCache for Redis clusters are running the latest service update by following these steps:

  1. Choose an applicable cluster on the Redis Clusters page

  2. Choose Service updates in the navigation pane to see the applicable service updates for that cluster, if any.

If the console displays a list of service updates, you can select the service update and choose Apply now.

Service updates console screenshot 1.

If the console displays “No service updates found”, it means the ElastiCache for Redis cluster already has the latest service update applied.

Service updates console screenshot 2.

Stopping the service updates

You can stop updates to clusters if needed. For example, you might want to stop updates if you have an unexpected surge to your clusters that are undergoing updates. Or you might want to stop updates if they're taking too long and interrupting your business flow at a peak time.

The Stopping operation immediately interrupts all updates to those clusters and any nodes that are yet to be updated. It continues to completion any nodes that have an in progress status. However, it ceases updates to other nodes in the same cluster that have an update available status and reverts them to a Stopping status.

When the Stopping workflow is complete, the nodes that have a Stopping status change to a Stopped status. Depending on the workflow of the update, some clusters won't have any nodes updated. Other clusters might include some nodes that are updated and others that still have an update available status.

You can return later to finish the update process as your business flows permit. In this case, choose the applicable clusters that you want to complete updates on, and then choose Apply Now. For more information, see Applying the service updates.

Using the console

You can interrupt a service update using the ElastiCache console. The following demonstrates how to do this:

  • After a service update has progressed on a selected cluster, the ElastiCache console displays the View/Stop Update tab at the top of the ElastiCache dashboard.

  • To interrupt the update, choose Stop Update.

  • When you stop the update, choose the cluster and examine the status. It reverts to a Stopping status and eventually a Stopped status.

Using the AWS CLI

You can interrupt a service update using the AWS CLI. The following code example shows how to do this.

For a replication group, do the following:

aws elasticache batch-stop-update-action --service-update-name sample-service-update --replication-group-ids my-replication-group-1 my-replication-group-2

For a cache cluster, do the following:

aws elasticache batch-stop-update-action --service-update-name sample-service-update --cache-cluster-ids my-cache-cluster-1 my-cache-cluster-2

For more information, see BatchStopUpdateAction.