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2) it is not using docker as the container runtime, it's using containerd, it's not an issue, just be aware of that as you won't see containers using classic docker commands
How to remove/install /remove microk8s ?
If you have a previous version of microk8s, you first need to uninstall it (upgrade is possible but it is not recommended between major versions so I recommend to uninstall as it's fast and safe)
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