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Upgrade K8s

Performing upgrades of Google GKE clusters by yourself can be complex and time-consuming. Using the Console makes this entire process simple and straightforward. Different strategies can be employed for upgrading Google GKE clusters.

Scope of Upgrade

There are three components that need to be upgraded during a GKE Cluster upgrade.

  1. GKE Control Plane
  2. Attached Node Pools (both Managed and Self Managed)
  3. Critical Add-Ons (coredns and kube-proxy)

The control plane always needs to be upgraded first, before the node pools and the critical add-ons.

The Controller automatically upgrades the critical cluster add-ons as part of the upgrade process, reducing the manual, operational burden for administrators.

Important

GKE cluster upgrades performed by the controller are always performed in a manner where the cluster and resident workloads never encounter any downtime.

Upgrade Steps

  1. In the Console, select the project with the cluster you want to upgrade.

  2. Select the settings icon, then select Upgrade Cluster.

    Select Upgrade Cluster

  3. Select the Version Upgrade Type.

    • Control Plane Only Upgrade - Upgrades the control plane only. The attached node pools are left untouched. Takes approximately 25-30 minutes.
    • Node Pool Upgrade - Upgrades the node pools only (Worker Node version). Takes approximately 10-15 minutes.

  4. When upgrading the Control Plane, select the Control Plane version to upgrade to.

  5. When upgrading the Node Pools:

    • Select the Worker Node version to upgrade to.
    • Select the node pools to be upgraded.

  6. Click Upgrade.

Upgrade Process

The upgrade process includes the following:

  • A number of preflight checks are performed before the upgrade is attempted.

  • When upgrading the control plane:

    • The GKE control plane is upgraded. This can be a time-consuming step.
    • Critical add-ons for the cluster, such as core-dns and kube-proxy, are upgraded to the required version.

  • The node pools will be upgraded to the selected Kubernetes version.

  • Once upgrades are complete, a round of post upgrade tests are performed to ensure that there are no loose ends and everything is as expected.

Upgrade Activity

The controller maintains a list of cluster activities, including any upgrades.

  • Clicking on the cluster name.
  • Clicking on the Activity tab.