Container Service for Kubernetes:Update an ACK Edge cluster

Why ACK Edge clusters need updates

• Reduced security and stability risks: New Kubernetes versions are usually released to add optimizations and patch security and stability vulnerabilities. Using outdated Kubernetes clusters may pose security and stability risks to your business.

• Improved technical support and customer service: ACK Edge no longer releases security patches or repairs for outdated Kubernetes versions. In addition, ACK Edge does not guarantee the quality of technical support for outdated Kubernetes versions. You can enjoy improved technical support and customer service when using new Kubernetes versions.

• New features: The iteration of open source Kubernetes introduces new features and improvements. ACK Edge clusters will also support these features to optimize your development and maintenance experience.

Usage notes

• ACK Edge supports cluster updates between versions from 1.18 to 1.22. However, you can update from the current Kubernetes version only to the next version. You cannot roll back an ACK Edge cluster to an earlier Kubernetes version.

  For example, to update the Kubernetes version of an ACK Edge cluster from 1.18 to 1.22, you must first update the cluster to 1.20, and then update the cluster to 1.22.

  Note

  You can update your ACK Edge clusters from Kubernetes 1.26 to later versions. If you want to update from Kubernetes 1.26 to 1.30, submit a ticket to apply to be added to a whitelist.

• In an ACK Edge cluster, edge node pools and the control plane can differ by at most two minor versions. For example, if the control plane runs Kubernetes 1.22, the edge node pools must run at least Kubernetes 1.20. Otherwise, the cluster may not work as expected.

Update procedure, methods, and duration

Update procedure

Preparations

• Log on to the ACK consoler. On the Clusters page, select the ACK Edge cluster that you want to update and check the current Kubernetes version of the cluster and the new version available in the Version column.

• Read the release notes for the Kubernetes versions supported by ACK Edge clusters to learn about the features of different Kubernetes versions. For more information, see Release notes for ACK Edge of Kubernetes 1.30.

Update the cluster

Your cluster must pass a precheck before you can update the control plane and on-cloud node pools of the cluster. If issues are reported in the precheck results, you must fix the issues before you start the update.

• Control plane update: Rolling updates are used to update control plane components, such as kube-apiserver, kube-controller-manager, and kube-scheduler.

• On-cloud node pool update: When you update an on-cloud node pool, you need to update the kubelet and the container runtime of the node pool. Node pools are updated in batches:

  • Node pools are updated one after one. Only one node pool is updated at a time.

  • Nodes in a node pool are updated in batches. The first batch includes one node. The number of nodes increases by the power of two in subsequent batches. The batch update policy still applies after you resume a paused update. You can specify the maximum batch size on the Node Pool Upgrade page. We recommend that you set the maximum batch size to 10.

• Edge node pool update: You need to run update commands on all nodes one after one in each edge node pool.

Update duration

• It requires about 5 minutes to update the control plane of an ACK Edge cluster.

• Nodes in an on-cloud node pool are updated in batches. Each batch update requires about 5 minutes.

• For an edge node pool, you need to run update commands on all nodes in the node pool. Therefore, the duration of an edge node pool update varies based on the number of nodes in the node pool.

Verify the update

Check whether the Kubernetes version of the cluster is updated, whether the node pools run as expected, and whether the business in the cluster runs as expected.

Procedure

 export REGION="" INTERCONNECT_MODE="" TARGET_CLUSTER_VERSION=""; export ARCH=$(uname -m | awk '{print ($1 == "x86_64") ? "amd64" : (($1 == "aarch64") ? "arm64" : "amd64")}') INTERNAL=$( [ "$INTERCONNECT_MODE" = "private" ] && echo "-internal" || echo "" ); wget http://aliacs-k8s-${REGION}.oss-${REGION}${INTERNAL}.aliyuncs.com/public/pkg/run/attach/${TARGET_CLUSTER_VERSION}/${ARCH}/edgeadm -O edgeadm; chmod u+x edgeadm;./edgeadm upgrade --interconnect-mode=${INTERCONNECT_MODE} --region=${REGION}

References

If your cluster fails a precheck before an update, refer to Cluster check items and suggestions on how to fix cluster issues.