Manually tracking Kubernetes version support cycles and scheduling upgrades is time-consuming and error-prone. Auto upgrade keeps your ACK Serverless cluster on a supported Kubernetes version by generating an upgrade schedule in advance, running a precheck, and upgrading the control plane within the maintenance window you define—without manual intervention.
Limitations
Auto upgrade is supported only for ACK Serverless clusters running Kubernetes 1.22 or later.
Why use auto upgrade
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ACK stops releasing new features, feature patches, or security patches for ACK Serverless clusters running outdated Kubernetes versions, and provides only limited technical support for those versions. For more information, see Risks in outdated Kubernetes versions. To ensure security and stability, use a Kubernetes version supported by ACK.
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Auto upgrade keeps your cluster on a supported Kubernetes version without manual scheduling, so you can use the features provided by newer Kubernetes versions.
How it works
After you configure an auto upgrade policy, ACK checks the overall orchestration strategy and schedules upgrades in batches—not immediately. Each upgrade plan is generated at least one day before the scheduled upgrade. The plan covers a precheck followed by the control plane upgrade, all within your configured maintenance window.
Upgrades cannot be rolled back, whether triggered automatically or manually. To skip a specific upgrade, cancel the plan manually. Canceling a plan affects only that upgrade; auto upgrade remains enabled and ACK continues scheduling future upgrades.
You can also manually upgrade the cluster at any time, even after enabling auto upgrade. See Manually upgrade a cluster for details.
Prerequisites
Before you begin, make sure you have:
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An ACK Serverless cluster running Kubernetes 1.22 or later
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Access to the ACK console
Enable auto upgrade
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Log on to the ACK console. In the left navigation pane, click Clusters.
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On the Clusters page, click the name of the target cluster. In the left-side pane, choose Operations > Upgrade Cluster.
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On the Upgrade Cluster page, configure the auto upgrade policy: ACK runs a precheck before the upgrade begins. The precheck verifies compatibility between the new Kubernetes version and the API server and cluster components. If the precheck fails, fix the issues shown on the Upgrade Cluster page and wait for ACK to retry. View precheck results, upgrade status, and upgrade history in the History section.
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Select an upgrade channel (Patch, Stable, or Rapid). See Upgrade channels for details.
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Set a maintenance window of at least 2 hours.
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(Optional) After the upgrade completes, go to the Clusters page and verify that the Kubernetes version has been updated.
Upgrade channels
The upgrade channel determines which Kubernetes version your cluster is automatically upgraded to. ACK supports three channels:
Example: Current cluster version is 1.26.3-aliyun.1. Available versions are 1.26.15-aliyun.1, 1.28.9-aliyun.1, and 1.30.1-aliyun.1 (latest minor: 1.30, second-latest minor: 1.28).
| Channel | Behavior | Target version |
|---|---|---|
| Patch | Upgrades to the latest patch version of the current minor version. No breaking changes. | 1.26.15-aliyun.1 |
| Stable | Upgrades to the latest patch version of the second-latest minor version. Stability is verified, but API and feature changes may apply. | 1.28.9-aliyun.1 |
| Rapid | Upgrades to the latest patch version of the latest minor version, giving you the newest Kubernetes community features. | 1.30.1-aliyun.1 |
For definitions of patch versions and minor versions, see Version guide.
Maintenance window
The maintenance window controls when ACK runs upgrade tasks. It applies to both auto upgrades and auto O&M operations on nodes in the cluster.
Set the maintenance window to at least 2 hours to give the cluster enough time to complete the upgrade.
If you change the maintenance window:
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Before an upgrade begins: The current upgrade plan is canceled.
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While an upgrade is in progress: The ongoing upgrade is canceled.
View and manage upgrade plans
Once an upgrade plan is generated, view its details on the O&M Plan tab of the cluster details page, or by calling the ListOperationPlans API.
To skip a scheduled upgrade, cancel the plan on the O&M Plan tab. Canceling a plan does not disable auto upgrade.
Upgrade notifications
If an upgrade fails, ACK sends notifications via text message, email, and internal site messages.
What's next
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To upgrade immediately without waiting for the auto upgrade schedule, manually upgrade the cluster:
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ACK console: Manually upgrade a cluster
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ACK API: UpgradeCluster
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To review supported Kubernetes versions, upgrade considerations, deprecated features, and deprecated APIs, see the Version guide.
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If you run large-scale production workloads on ACK Serverless Basic clusters, consider migrating to ACK Serverless Pro clusters. See ACK Serverless Pro clusters for details.