Upgrading GKE on-prem

This page explains how to upgrade GKE on-prem.

Target versions

Starting with GKE on-prem version 1.3.2, you can upgrade directly to any version that is in the same minor release or the next minor release. For example, you can upgrade from 1.3.2 to 1.3.5, or from 1.5.2 to 1.6.1.

If your current version is lower than 1.3.2, then you must do sequential upgrades to reach version 1.3.2 first. For example, to upgrade from 1.3.0 to 1.3.2, you must first upgrade from 1.3.0 to 1.3.1, and then from 1.3.1 to 1.3.2.

If you are upgrading from version 1.3.2 or later to a version that is not part of the next minor release, you must upgrade through one version of each minor release between your current version and your desired version. For example, if you are upgrading from version 1.3.2 to version 1.6.1, it is not possible to upgrade directly. You must first upgrade from version 1.3.2 to version 1.4.x, where x represents any patch release under that minor release. You can then upgrade to version 1.5.x, and finally to version 1.6.1.

Overview of the upgrade process

1. Download the gkeadm tool. The version of gkeadm must be the same as the target version of your upgrade.

2. Use gkeadm to upgrade your admin workstation.

3. From your admin workstation, upgrade your admin cluster.

4. From your admin workstation, upgrade your user clusters.

Upgrade policy

After you upgrade your admin cluster:

• Any new user clusters that you create must have the same version as your admin cluster.

• If you upgrade an existing user cluster, you must upgrade to the same version as your admin cluster.

• Before you upgrade your admin cluster again, you must upgrade all of your user clusters to the same version as your current admin cluster.

Locating your configuration and information files

When you created your current admin workstation, you filled in an admin workstation configuration file that was generated by gkeadm create config. The default name for this file is admin-ws-config.yaml.

When you created your current admin workstation, gkeadm created an information file for you. The default name of this file is the same as the name of your current admin workstation.

Locate your admin workstation configuration file and your information file. You need them to do the steps in this guide. If these files are in your current directory and they have their default names, then you won't need to specify them when you run gkeadm upgrade admin-workstation. If these files are in another directory, or if you have changed the filenames, then you specify them by using the --config and --info-file flags.

Upgrading your admin workstation

To upgrade your admin workstation, first download a new version of the gkeadm tool, and then use it to upgrade the configuration of your admin workstation. The version of gkeadm must match the target version of your upgrade.

Downloading gkeadm

To download the current version of gkeadm, follow the gkeadm download instructions on the Downloads page.

Upgrading your admin workstation configuration

gkeadm upgrade admin-workstation --config [AW_CONFIG_FILE] --info-file [INFO_FILE]

where:

• [AW_CONFIG_FILE] is the path of your admin workstation configuration file. You can omit this flag if the file is in your current directory and has the name admin-ws-config.yaml.

• [INFO_FILE] is the path of your information file. You can omit this flag if the file is in your current directory. The default name of this file is the same as the name of your admin workstation.

The preceding command performs the following tasks:

• Back up all files in the home directory of your current admin workstation. These include:

  • Your GKE on-prem configuration file. The default name of this file is config.yaml.

  • The kubeconfig files for your admin cluster and your user clusters.

  • The root certificate for your vCenter server. Note that this file must have owner read and owner write permission.

  • The JSON key file for your component access service account. Note that this file must have owner read and owner write permission.

  • The JSON key files for your connect-register, connect-agent, and logging-monitoring service accounts.

• Create a new admin workstation, and copy all the backed-up files to the new admin workstation.

• Delete the old admin workstation.

Removing the old admin workstation from known_hosts

If your admin workstation has a static IP address, you need to remove your old admin workstation from the known_hosts file after upgrading your admin workstation.

To remove the old admin workstation from known_hosts:

ssh-keygen -R [ADMIN_WS_IP]

where [ADMIN_WS_IP] is the IP address of your admin workstation.

Setting the bundle path in your GKE on-prem configuration file

On your new admin workstation, open your GKE on-prem configuration file. Set the value of bundlepath to the path of the bundle file on your new admin workstation:

bundlepath: "/var/lib/gke/bundles/gke-onprem-vsphere-[VERSION]-full.tgz"

where [VERSION] is the target version of your upgrade.

Updating the node OS image and Docker images

On your new admin workstation, run the following command:

gkectl prepare --config [CONFIG_FILE] [FLAGS]

where:

• [CONFIG_FILE] is the GKE on-prem configuration file on your new admin workstation.

• [FLAGS] is an optional set of flags. For example, you could include the --skip-validation-infra flag to skip checking of your vSphere infrastructure.

The preceding command performs the following tasks:

• If necessary, copy a new node OS image to your vSphere environment, and mark the OS image as a template.

• If you have configured a private Docker registry, push updated Docker images to your private Docker registry.

Verify that enough IP addresses are available

Do the steps in this section on your new admin workstation.

Before you upgrade, be sure that you have enough IP addresses available for your clusters. You can set aside additional IPs as needed, as described for each of DHCP and static IPs.

DHCP

When you upgrade the admin cluster, GKE on-prem creates one temporary node in the admin cluster. When you upgrade a user cluster, GKE on-prem creates a temporary node in that user cluster. The purpose of the temporary node is to ensure uninterrupted availability. Before you upgrade a cluster, make sure that your DHCP server can provide enough IP addresses for the temporary node. For more information, see IP addresses needed for admin and user clusters.

Static IPs

When you upgrade the admin cluster, GKE on-prem creates one temporary node in the admin cluster. When you upgrade a user cluster, GKE on-prem creates a temporary node in that user cluster. The purpose of the temporary node is to ensure uninterrupted availability. Before you upgrade a cluster, verify that you have reserved enough IP addresses. For each cluster, you must reserve at least one more IP address than the number of cluster nodes. For more information, see Configuring static IP addresses.

Determine the number of nodes in your admin cluster:

kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] get nodes

where [ADMIN_CLUSTER_KUBECONFIG] is the path of your admin cluster's kubeconfig file.

Next, view the addresses reserved for your admin cluster:

kubectl get cluster --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] -o yaml

In the output, in the reservedAddresses field, you can see the number of IP addresses that are reserved for the admin cluster nodes. For example, the following output shows that there are five IP addresses reserved for the admin cluster nodes::

...
reservedAddresses:
- gateway: 21.0.135.254
  hostname: admin-node-1
  ip: 21.0.133.41
  netmask: 21
- gateway: 21.0.135.254
  hostname: admin-node-2
  ip: 21.0.133.50
  netmask: 21
- gateway: 21.0.135.254
  hostname: admin-node-3
  ip: 21.0.133.56
  netmask: 21
- gateway: 21.0.135.254
  hostname: admin-node-4
  ip: 21.0.133.47
  netmask: 21
- gateway: 21.0.135.254
  hostname: admin-node-5
  ip: 21.0.133.44
  netmask: 21

The number of reserved IP addresses should be at least one more than the number of nodes in the admin cluster. If this is not the case, you can reserve an additional address by editing the Cluster object.

Open the Cluster object for editing:

kubectl edit cluster --kubeconfig [ADMIN_CLUSTER_KUBECONFIG]

Under reservedAddresses, add an additional block that has gateway, hostname, ip, and netmask.

Important: Starting from 1.5.0, the same procedure does not work for user clusters and you must use gkectl update cluster for each of them.

To determine the number of nodes in a user cluster:

kubectl --kubeconfig [USER_CLUSTER_KUBECONFIG] get nodes

where [USER_CLUSTER_KUBECONFIG] is the path of your user cluster's kubeconfig file.

To view the addresses reserved for a user cluster:

kubectl get cluster --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] \
-n [USER_CLUSTER_NAME] [USER_CLUSTER_NAME] -o yaml

where:

• [ADMIN_CLUSTER_KUBECONFIG] is the path of your admin cluster's kubeconfig file.

• [USER_CLUSTER_NAME] is the name of the user cluster.

The number of reserved IP addresses should be at least one more than the number of nodes in the user cluster. If this is not the case, you can open the user cluster's hostconfig file for editing:

• If any of the addresses reserved for a user cluster are included in the hostconfig file, add them to the corresponding block based on netmask and gateway.

• Add as many additional static IP addresses to the corresponding block as required, and then run gkectl update cluster.

(Optional) Disabling new vSphere features

A new GKE on-prem version might include new features or support for specific VMware vSphere features. Sometimes, upgrading to a GKE on-prem version automatically enables such features. You learn about new features in GKE on-prem's Release notes. New features are sometimes surfaced in the GKE on-prem configuration file.

If you need to disable a new feature that is automatically enabled in a new GKE on-prem version and driven by the configuration file, perform the following steps before you upgrade your cluster:

1. From your upgraded admin workstation, create a new configuration file with a different name from your current configuration file:

   gkectl create-config --config [CONFIG_NAME]

2. Open the new configuration file and make a note of the feature's field. Close the file.

3. Open your current configuration file and add the new feature's field. Set the value of the field to false or equivalent.

4. Save the configuration file.

Review the Release notes before you upgrade your clusters. You cannot declaratively change an existing cluster's configuration after you upgrade it.

Upgrading your admin cluster

Note: Before you begin this upgrade, determine if your certificates are up to date, and renew them if necessary.

Do the steps in this section on your new admin workstation.

Recall that the target version of your upgrade must be the same as your gkeadm version.

Run the following command:

gkectl upgrade admin \
--kubeconfig [ADMIN_CLUSTER_KUBECONFIG] \
--config [ADMIN_CLUSTER_CONFIG_FILE] \
[FLAGS]

where:

• [ADMIN_CLUSTER_KUBECONFIG] is the admin cluster's kubeconfig file.

• [ADMIN_CLUSTER_CONFIG_FILE] is the GKE on-prem admin cluster configuration file on your new admin workstation.

• [FLAGS] is an optional set of flags. For example, you could include the --skip-validation-infra flag to skip checking of your vSphere infrastructure.

Note: This does not upgrade all the nodes in the admin cluster because some of the nodes in the admin cluster are the primary nodes for user clusters. Those will upgrade when you start the user clusters upgrade.

Note: The gkectl upgrade command runs preflight checks. If the preflight checks fail, the command is blocked. You must fix the failures or use the flag --skip-preflight-check-blocking with the command to unblock it.

Upgrading a user cluster

Do the steps in this section on your new admin workstation.

Recall that the target version of your upgrade must be the same as your gkeadm version.

Note: The gkectl upgrade command runs preflight checks. If the preflight checks fail, the command is blocked. You must fix the failures or use the flag --skip-preflight-check-blocking with the command to unblock it.

gkectl

gkectl upgrade cluster \
--kubeconfig [ADMIN_CLUSTER_KUBECONFIG] \
--config [USER_CLUSTER_CONFIG_FILE] \
--cluster-name [CLUSTER_NAME] \
[FLAGS]

where:

• [ADMIN_CLUSTER_KUBECONFIG] is the admin cluster's kubeconfig file.

• [CLUSTER_NAME] is the name of the user cluster you're upgrading.

• [USER_CLUSTER_CONFIG_FILE] is the GKE on-prem user cluster configuration file on your new admin workstation.

• [FLAGS] is an optional set of flags. For example, you could include the --skip-validation-infra flag to skip checking of your vSphere infrastructure.

Note: The --cluster-name [CLUSTER_NAME] flag still works but will be disabled in a future release.

Console

You can choose to register your user clusters with Google Cloud console during installation or after you've created them. You can view and log in to your registered GKE on-prem clusters and your Google Kubernetes Engine clusters from Google Cloud console's GKE menu.

When an upgrade becomes available for GKE on-prem user clusters, a notification appears in Google Cloud console. Clicking this notification displays a list of available versions and a gkectl command you can run to upgrade the cluster:

1. Visit the GKE menu in Google Cloud console.

   Visit the GKE menu

2. Under the Notifications column for the user cluster, click Upgrade available, if available.

3. Copy the gkectl upgrade cluster command.

4. From your admin workstation, run the gkectl upgrade cluster command, where [ADMIN_CLUSTER_KUBECONFIG] is the admin cluster's kubeconfig file, [CLUSTER_NAME] is the name of the user cluster you're upgrading, and [USER_CLUSTER_CONFIG_FILE] is the GKE on-prem user cluster configuration file on your new admin workstation.

Resuming an upgrade

If a user cluster upgrade is interrupted after the admin cluster is successfully upgraded, you can resume the user cluster upgrade by running the same upgrade command with the --skip-validation-all flag:

gkectl upgrade cluster \
--kubeconfig [ADMIN_CLUSTER_KUBECONFIG] \
--config [USER_CLUSTER_CONFIG_FILE] \
--cluster-name [CLUSTER_NAME] \
--skip-validation-all

Resuming an admin cluster upgrade

You shouldn't interrupt an admin cluster upgrade. Currently, admin cluster upgrades aren't always resumable. If an admin cluster upgrade is interrupted for any reason, you should contact support for assistance.

Creating new user cluster after an upgrade

After you upgrade your admin workstation and your admin cluster, any new user clusters that you create must have the same version as the upgrade target version.

Known issues

The following known issues affect upgrading clusters.

Version 1.1.0-gke.6, 1.2.0-gke.6: stackdriver.proxyconfigsecretname field removed

The stackdriver.proxyconfigsecretname field was removed in version 1.1.0-gke.6. GKE on-prem's preflight checks will return an error if the field is present in your configuration file.

To work around this, before you upgrade to 1.2.0-gke.6, delete the proxyconfigsecretname field from your configuration file.

Stackdriver references old version

Before version 1.2.0-gke.6, a known issue prevents Stackdriver from updating its configuration after cluster upgrades. Stackdriver still references an old version, which prevents Stackdriver from receiving the latest features of its telemetry pipeline. This issue can make it difficult for Google Support to troubleshoot clusters.

After you upgrade clusters to 1.2.0-gke.6, run the following command against admin and user clusters:

kubectl --kubeconfig=[KUBECONFIG] \
-n kube-system --type=json patch stackdrivers stackdriver \
-p '[{"op":"remove","path":"/spec/version"}]'

where [KUBECONFIG] is the path to the cluster's kubeconfig file.

Disruption for workloads with PodDisruptionBudgets

Currently, upgrading clusters can cause disruption or downtime for workloads that use PodDisruptionBudgets (PDBs).

Version 1.2.0-gke.6: Prometheus and Grafana disabled after upgrading

In user clusters, Prometheus and Grafana get automatically disabled during upgrade. However, the configuration and metrics data are not lost. In admin clusters, Prometheus and Grafana stay enabled.

For instructions, refer to the GKE on-prem release notes.

Version 1.1.2-gke.0: Deleted user cluster nodes aren't removed from vSAN datastore

For instructions, refer to the GKE on-prem release notes.

Version 1.1.1-gke.2: Data disk in vSAN datastore folder can be deleted

If you're using a vSAN datastore, you need to create a folder in which to save the VMDK. A known issue requires that you provide the folder's universally unique identifier (UUID) path, rather than its file path, to vcenter.datadisk. This mismatch can cause upgrades to fail.

For instructions, refer to the GKE on-prem release notes.

Upgrading to version 1.1.0-gke.6 from version 1.0.2-gke.3: OIDC issue

Version 1.0.11, 1.0.1-gke.5, and 1.0.2-gke.3 clusters that have OpenID Connect (OIDC) configured cannot be upgraded to version 1.1.0-gke.6. This issue is fixed in version 1.1.1-gke.2.

If you configured a version 1.0.11, 1.0.1-gke.5, or 1.0.2-gke.3 cluster with OIDC during installation, you are not able to upgrade it. Instead, you should create new clusters.

Upgrading to version 1.0.2-gke.3 from version 1.0.11

Version 1.0.2-gke.3 introduces the following OIDC fields (usercluster.oidc). These fields enable logging in to a cluster from Google Cloud console:

• usercluster.oidc.kubectlredirecturl
• usercluster.oidc.clientsecret
• usercluster.oidc.usehttpproxy

If you want to use OIDC, the clientsecret field is required even if you don't want to log in to a cluster from Google Cloud console. To use OIDC, you might need to provide a placeholder value for clientsecret:

oidc:
  clientsecret: "secret"

Nodes fail to complete their upgrade process

If you have PodDisruptionBudget objects configured that are unable to allow any additional disruptions, node upgrades might fail to upgrade to the control plane version after repeated attempts. To prevent this failure, we recommend that you scale up the Deployment or HorizontalPodAutoscaler to allow the node to drain while still respecting the PodDisruptionBudget configuration.

To see all PodDisruptionBudget objects that do not allow any disruptions:

kubectl get poddisruptionbudget --all-namespaces -o jsonpath='{range .items[?(@.status.disruptionsAllowed==0)]}{.metadata.name}/{.metadata.namespace}{"\n"}{end}'

Appendix

About VMware DRS rules enabled in version 1.1.0-gke.6

As of version 1.1.0-gke.6, GKE on-prem automatically creates VMware Distributed Resource Scheduler (DRS) anti-affinity rules for your user cluster's nodes, causing them to be spread across at least three physical hosts in your datacenter. As of version 1.1.0-gke.6, this feature is automatically enabled for new clusters and existing clusters.

Before you upgrade, be sure that your vSphere environment meets the following conditions:

• VMware DRS is enabled. VMware DRS requires vSphere Enterprise Plus license edition. To learn how to enable DRS, see Enabling VMware DRS in a cluster
• The vSphere user account provided in the vcenter field has the Host.Inventory.EditCluster permission.
• There are at least three physical hosts available.

If your vSphere environment does not meet the preceding conditions, you can still upgrade, but for upgrading a user cluster from 1.3.x to 1.4.x, you need to disable anti-affinity groups. For more information, see this known issue in the GKE on-prem release notes..

Down time

About downtime during upgrades

Resource	Description
Admin cluster	When an admin cluster is down, user cluster control planes and workloads on user clusters continue to run, unless they were affected by a failure that caused the downtime
User cluster control plane	Typically, you should expect no noticeable downtime to user cluster control planes. However, long-running connections to the Kubernetes API server might break and would need to be re-established. In those cases, the API caller should retry until it establishes a connection. In the worst case, there can be up to one minute of downtime during an upgrade. Note: If user cluster nodes are unable reach the user control plane during the upgrade, new workloads are not scheduled to the cluster. Existing workloads are unaffected.
User cluster nodes	If an upgrade requires a change to user cluster nodes, GKE on-prem recreates the nodes in a rolling fashion, and reschedules Pods running on these nodes. You can prevent impact to your workloads by configuring appropriate PodDisruptionBudgets and anti-affinity rules.

Troubleshooting

For more information, refer to Troubleshooting.

Diagnosing cluster issues using gkectl

Use gkectl diagnosecommands to identify cluster issues and share cluster information with Google. See Diagnosing cluster issues.

Default logging behavior

For gkectl and gkeadm it is sufficient to use the default logging settings:

• By default, log entries are saved as follows:

  • For gkectl, the default log file is /home/ubuntu/.config/gke-on-prem/logs/gkectl-$(date).log, and the file is symlinked with the logs/gkectl-$(date).log file in the local directory where you run gkectl.
  • For gkeadm, the default log file is logs/gkeadm-$(date).log in the local directory where you run gkeadm.
• All log entries are saved in the log file, even if they are not printed in the terminal (when --alsologtostderr is false).
• The -v5 verbosity level (default) covers all the log entries needed by the support team.
• The log file also contains the command executed and the failure message.

We recommend that you send the log file to the support team when you need help.

Specifying a non-default location for the log file

To specify a non-default location for the gkectl log file, use the --log_file flag. The log file that you specify will not be symlinked with the local directory.

To specify a non-default location for the gkeadm log file, use the --log_file flag.

Locating Cluster API logs in the admin cluster

If a VM fails to start after the admin control plane has started, you can try debugging this by inspecting the Cluster API controllers' logs in the admin cluster:

1. Find the name of the Cluster API controllers Pod in the kube-system namespace, where [ADMIN_CLUSTER_KUBECONFIG] is the path to the admin cluster's kubeconfig file:

   kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] -n kube-system get pods | grep clusterapi-controllers

2. Open the Pod's logs, where [POD_NAME] is the name of the Pod. Optionally, use grep or a similar tool to search for errors:

   kubectl --kubeconfig [ADMIN_CLUSTER_KUBECONFIG] -n kube-system logs [POD_NAME] vsphere-controller-manager