Release channels
Managed Service for Kubernetes provides updates through release channels.
The service supports three Kubernetes release channels. Master node and Managed Service for Kubernetes node group versions are independent; therefore, you can specify different Kubernetes versions from a single release channel when creating them.
Warning
If you need to upgrade both the master node and the node group, upgrade the master node first.
When creating a Managed Service for Kubernetes cluster, specify one of the three release channels. You cannot change the channel after the Managed Service for Kubernetes cluster is created. You can only recreate the cluster and specify a new release channel. The table below describes the release channels and supported Kubernetes versions.
| Channel | Kubernetes versions | Auto updates | Channel description |
|---|---|---|---|
rapid |
1.30, 1.31, 1.32, 1.33, 1.34 | Auto updates cannot be disabled. You can specify a time period for auto updates. | A channel receives updates with new features and improvements first. |
regular |
1.30, 1.31, 1.32, 1.33 | Auto updates can be disabled. | New features and improvements are added shortly after they appear on rapid. |
stable |
1.30, 1.31, 1.32 | Auto updates can be disabled. | New features and improvements are added shortly after they appear on regular. |
Warning
Starting from Kubernetes version 1.30, in the RAPID release channel, the basic node image is changed from Ubuntu 20.04 to Ubuntu 22.04. In the existing clusters and node groups, the OS version will be upgraded using the method you select. This upgrade will later become available in the REGULAR and STABLE release channels.
For OS upgrade details and recommendations, see Updating node group OS.
Updates
When a release channel receives an update, you get a notification in the management console. You can install updates automatically or manually.
-
Auto updates are installed within the specified time period. They do not require any user actions.
Updates are initiated and should be completed within this time period. In some cases, when updating a Managed Service for Kubernetes node group, an update may continue beyond this period.
Auto updates include new Managed Service for Kubernetes features, improvements, and fixes, as well as Kubernetes component fixes.
-
Manual updates can be initiated by the user at any time.
They include Kubernetes minor version updates. Note that you can only update to one minor version at a time.
For example, from 1.31 to 1.32.
The difference between the cluster and node group versions must not be more than two minor versions. The node group version cannot be higher than the cluster version.
For example, if the cluster version is 1.33, the node group version may be 1.33, 1.32, or 1.31
Note
for compatibility of objects or configurations with the new Kubernetes version is automatically performed before cluster upgrade. If the check finds incompatible objects or configurations, the upgrade will return an error with a list of incompatible resources and a description.
Read more about the end of support for Kubernetes versions and how different Managed Service for Kubernetes cluster components are updated.
End of support for a Kubernetes version
When upgrading from a Kubernetes version that is no longer supported:
- The Managed Service for Kubernetes master is not auto updated, you need to do it manually.
- Minor versions (e.g., 1.20 to 1.21) must be updated manually.
- Managed Service for Kubernetes node groups are updated automatically if auto updates are enabled. If auto updates are disabled, the old version of Kubernetes remains on the Managed Service for Kubernetes node groups. In this case, the user has to deal with any issues with their Managed Service for Kubernetes node group on their own, since the old version of Kubernetes is no longer supported.
Updating Kubernetes cluster components
The update process is different for a Managed Service for Kubernetes master and a node group.
Master
The amount of time a Managed Service for Kubernetes master is unavailable during an update depends on the master type:
- The basic master is unavailable during the update.
- The highly available master maintains network connectivity during the update.
For more information, see Updating a cluster.
Node group
You can update a Managed Service for Kubernetes node group with additional resources allocated by creating nodes with a new configuration.
Warning
For a successful update with additional resources, you should have enough quotas to create one additional Managed Service for Kubernetes node.
The Managed Service for Kubernetes node group update algorithm is as follows:
- An updated node is created with the configuration specified for the entire Managed Service for Kubernetes node group.
- All the pods are evicted from one of the old Managed Service for Kubernetes nodes based on the pre-defined
PodDisruptionBudgetspolicy. Then the node is deleted. - The process is repeated until all the Managed Service for Kubernetes nodes in the group are updated.
This ensures that the number of nodes in the group never falls below the number specified when creating a Managed Service for Kubernetes node group.
You can specify the maximum number of VM instances by which you can expand or reduce the size of the Managed Service for Kubernetes group when updating it. For more information, see Updating a node group.
Certificates
In accordance with the safety recommendations, Managed Service for Kubernetes cluster and node group certificates are valid for one year. When a certificate expires, a Managed Service for Kubernetes cluster or node group will be disabled. To avoid this, Managed Service for Kubernetes automatically updates their certificates.
- If automatic updates are enabled, certificates are auto updated whenever a Managed Service for Kubernetes cluster or node group updates.
- If automatic updates are disabled, a certificate update will be forced a week before they expire.
For more information about updating certificates, see this Kubernetes guide.