After you enable auto updates for a Container Service for Kubernetes (ACK) Serverless cluster, the Kubernetes version of the cluster is automatically upgraded on a regular basis. This simplifies your O&M work. Once an auto update policy is configured, the system automatically generates an update schedule in advance, and runs a precheck and upgrades the control planes of the cluster within the maintenance window of the cluster. This allows you to focus on application development.
Limits
You can enable auto updates only for ACK Serverless clusters that run Kubernetes 1.22 or later.
Benefits of auto updates
ACK stops releasing new features, feature patches, or security patches for ACK Serverless clusters that run outdated Kubernetes versions. ACK only provides limited technical support for these Kubernetes versions. For more information, see Risks in outdated Kubernetes versions. To ensure security and stability, we recommend that you use the Kubernetes versions supported by ACK.
Auto updates simplify your O&M work. Once enabled, ACK updates the Kubernetes version of your cluster to a later version supported by ACK on a regular basis. This allows you to use the new features provided by the new Kubernetes version.
Auto update policies
After you configure an auto update policy for your cluster, ACK automatically generates an update schedule based on the policy and the Kubernetes versions supported by the ACK Serverless cluster. ACK runs upgrade tasks in the cluster within the maintenance window specified in the update schedule. You can configure the maintenance window and update frequency in an auto update policy. After you enable auto updates for a cluster, ACK does not immediately upgrade the cluster. If an immediate upgrade is required, manually upgrade a cluster.
ACK uses the same procedure to upgrade a cluster, regardless of whether the cluster is automatically upgraded or manually upgraded. You still can manually upgrade a cluster after enabling auto updates.
You cannot roll back manual upgrades or auto upgrades. For more precautions about manual upgrades, see Manually upgrade a cluster.
Maintenance window
You can specify a maintenance window for each cluster. The maintenance window is applied in the auto updates of a cluster and the auto O&M of s in the cluster. ACK automatically generates an update schedule based on the specified maintenance window and runs a precheck and upgrade tasks within the maintenance window.
If the change is made before a scheduled upgrade begins: The scheduled upgrade plan will be automatically canceled.
If the change is made while an upgrade is in progress: The ongoing upgrade operation will be canceled.
To ensure a sufficient time for cluster updates, set the maintenance window to at least 2 hours.
Update frequency
You can select different update frequencies based on your requirements.
For example, if your current cluster is version 1.26.3-aliyun.1, the latest version is 1.30, and the second-latest version is 1.28, you can upgrade to the following three versions: 1.26.15-aliyun.1, 1.28.9-aliyun.1, and 1.30.1-aliyun.1. The following table describes the update frequency and the specific version to which your cluster will automatically upgrade under different frequencies.
channel | Description | New version |
Patch | If a patch version is available for the current minor version, the cluster is automatically upgraded to the patch version. The new Kubernetes version does not contain breaking changes. | 1.26.15-aliyun.1 |
Stable | Automatically upgrade to the latest patch version of the second-latest minor version. The new Kubernetes version may involve changes in APIs and features, but its stability is verified. | 1.28.9-aliyun.1 |
Rapid | Automatically upgrade to the latest patch version of the latest minor version to quickly obtain new features provided by the Kubernetes community. | 1.30.1-aliyun.1 |
For more information about patch versions and minor versions, see Version guide.
Update schedule
Based on your configured auto update policy and the release schedule of new ACK versions, the system will check if your cluster is eligible for an auto upgrade. If your cluster is eligible, an update plan will be generated at least one day in advance. You can view the plan's details in the ACK console or through the OpenAPI.
To skip a scheduled upgrade, cancel it manually. Canceling a plan only affects the current scheduled upgrade; it does not disable the auto update feature. ACK will continue to schedule future upgrades for your ACK Serverless cluster during its maintenance window.
Once an auto update policy is configured, the system does not perform the upgrade immediately. Instead, upgrade plans are scheduled in advance based on the overall orchestration strategy, and are then rolled out in batches over time.
Once an upgrade plan is generated, you can view its details on the O&M Plan tab in the cluster details page or by calling the ListOperationPlans API.
The purpose of upgrade prechecks is to verify the compatibility between the new Kubernetes version and the Kubernetes API server and cluster components. If the cluster fails a precheck, you must fix the issues. Then, ACK runs a precheck again. You can view the details of precheck failures in the History section of the Upgrade Cluster page.
Update notifications
If an upgrade fails for an ACK Serverless cluster, you will receive a notification via text message, email, and internal site messages.
Enable auto updates
After you enable auto updates for an ACK Serverless cluster, ACK checks the overall scheduling policy and then runs upgrade tasks within a maintenance window.
Log on to the ACK console. In the left navigation pane, click Clusters.
On the Clusters page, find the cluster you want and click its name. In the left-side pane, choose .
On the Upgrade Cluster page, configure the auto update policy and the maintenance window based on the instructions in the Auto update policies section.
ACK performs a precheck before running auto upgrade tasks. If your cluster fails a precheck, you must fix the issues based on the details displayed on the Upgrade Cluster page. You can view precheck details, upgrade status, and upgrade details in the History section.
You can manually cancel the schedule if needed.
(Optional) After an upgrade is completed, you can check the Kubernetes version of the cluster on the Clusters page to confirm that the upgrade is successful.
References
If auto updates cannot meet your requirements, you can manually upgrade your cluster:
Use the ACK console: Manually upgrade a cluster.
Use the ACK API: UpgradeCluster.
If you use ACK Serverless Basic clusters to run large-scale services in production environments, we recommend performing hot migration from ACK Serverless Basic clusters to ACK Serverless Pro clusters. See ACK Serverless Pro clusters for cluster details.
For details on Kubernetes version supported by ACK Serverless cluster, see Version guide. You can also learn about upgrade considerations, new features, deprecated features, and deprecated APIs of each Kubernetes version.