This page will outline how to manage and execute a Kubernetes upgrade.
This page assumes you have a working Juju deployed cluster.
You should always back up all your data before attempting an upgrade. Don’t forget to include the workload inside your cluster! Refer to the backup documentation.
See if upgrades are available. The Kubernetes charms are updated bi-monthly and mentioned in the Kubernetes release notes. Important operational considerations and change in behaviour will always be documented in the release notes.
You can use
juju status to see if an upgrade is available. There will either be an upgrade to kubernetes or etcd, or both.
Backing up etcd requires an export and snapshot, refer to the backup documentation to create a snapshot. After the snapshot upgrade the etcd service with:
juju upgrade-charm etcd
This will handle upgrades between minor versions of etcd. Major upgrades from etcd 2.x to 3.x are currently unsupported. Upgrade viability will be investigated when etcd 3.0 is finalized.
First you need to upgrade the masters:
juju upgrade-charm kubernetes-master
NOTE: Always upgrade the masters before the workers.
Two methods of upgrading workers are supported. Blue/Green Deployment and upgrade-in-place. Both methods are provided for operational flexibility and both are supported and tested. Blue/Green will require more hardware up front than inplace, but is a safer upgrade route.
Given the following deployment, where the workers are named kubernetes-alpha.
Deploy new worker(s):
juju deploy kubernetes-beta
Pause the old workers so your workload migrates:
juju action kubernetes-alpha/# pause
Verify old workloads have migrated with:
kubectl get-pod -o wide
Tear down old workers with:
juju remove-application kubernetes-alpha
juju upgrade-charm kubernetes-worker
kubectl version should return the newer version.
It is recommended to rerun a cluster validation to ensure that the cluster upgrade has successfully completed.
Upgrading flannel can be done at any time, it is independent of Kubernetes upgrades. Be advised that networking is interrupted during the upgrade. You can initiate a flannel upgrade:
juju upgrade-charm flannel
Upgrading easyrsa can be done at any time, it is independent of Kubernetes upgrades. Upgrading easyrsa should result in zero downtime as it is not a running service:
juju upgrade-charm easyrsa
At this time rolling back etcd is unsupported.
At this time rolling back Kubernetes is unsupported.Create an Issue Edit this Page