Microk8s is a snap deploying Kubernetes. Upstream Kubernetes ships a new release about every three months, while old releases get periodic updates. At the time of this writing the latest release series is v1.12 with v1.12.0 being the latest release. On the v1.11 series, v1.11.3 is the latest release. It is important to remember that upstream Kubernetes is committed to maintain backwards compatibility only within a release series. That means that your Kubernetes will not break due to API changes when you upgrade from v1.11.x to v1.11.y but may break if you upgrade from v1.11.x to v1.12.z.
When installing MicroK8s you can select your desired upstream Kubernetes series with the corresponding snap channel. For example, to install MicroK8s and let it follow the v1.12 release series you:
snap install microk8s --classic --channel=1.12/stable
If you omit the --channel argument MicroK8s will follow the latest stable upstream Kubernetes. This means that your deployment will eventually upgrade to a new release series. At the time of this writing you will get v1.12.0 with:
snap install microk8s --classic
Since no --channel is specified such deployment will eventually upgrade to v1.13.0.
Switching from one channel to another is done with snap refresh --channel=<new_channel>. For example, switch MicroK8s to the v1.11 release series with:
snap install microk8s --channel=1.11/stable
The */stable channels serve the latest stable upstream Kubernetes release of the respective release series. Upstream releases are propagated to the MicroK8s snap in about a week. This means your MicroK8s will upgrade to the latest upstream release in your selected channel roughly one week after the upstream release.
The */candidate and */beta channels get updated within hours of an upstream release. Getting a MicroK8s deployment pointing to 1.12/beta is as simple as:
snap install microk8s --classic --channel=1.12/beta
The */edge channels get updated for each MicroK8s patch or upstream Kubernetes release.
Keep in mind that edge and beta are snap constructs and do not relate to Kubernetes release names.
To always track the latest stable Kubernetes versions:
snap install microk8s --classic
To track the latest version in a specific release series:
snap install microk8s --classic --channel=<track>/stable