MKE is designed to scale as your applications grow in size and usage. You can add and remove nodes from the cluster to make it scale to your needs.
You can also uninstall MKE from your cluster. In this case, the MKE services are stopped and removed, but your Mirantis Container Runtimes will continue running in swarm mode. You applications will continue running normally.
If you wish to remove a single node from the MKE cluster, you should instead remove that node from the cluster.
After you uninstall MKE from the cluster, you’ll no longer be able to
enforce role-based access control (RBAC) to the cluster, or have a
centralized way to monitor and manage the cluster. After uninstalling
MKE from the cluster, you will no longer be able to join new nodes using
docker swarm join, unless you reinstall MKE.
To uninstall MKE, log in to a manager node using ssh, and run the following command:
docker container run --rm -it \ -v /var/run/docker.sock:/var/run/docker.sock \ --name ucp \ mirantis/ucp:3.3.16 uninstall-ucp --interactive
This runs the uninstall command in interactive mode, so that you are prompted for any necessary configuration values.
uninstall-ucp command fails, you can run the following
commands to manually uninstall MKE:
#Run the following command on one manager node to remove remaining MKE services docker service rm $(docker service ls -f name=ucp- -q) #Run the following command on each manager node to remove remaining MKE containers docker container rm -f $(docker container ps -a -f name=ucp- -f name=k8s_ -q) #Run the following command on each manager node to remove remaining MKE volumes docker volume rm $(docker volume ls -f name=ucp -q)
The MKE configuration is kept in case you want to reinstall MKE with the
same configuration. If you want to also delete the configuration, run
the uninstall command with the
Refer to the CLI Reference documentation to see the available options.
Once the uninstall command finishes, MKE is completely removed from all the nodes in the cluster. You don’t need to run the command again from other nodes.
Swarm mode CA¶
After uninstalling MKE, the nodes in your cluster will still be in swarm
mode, but you can’t join new nodes until you reinstall MKE, because
swarm mode relies on MKE to provide the CA certificates that allow nodes
in the cluster to identify one another. Also, since swarm mode is no
longer controlling its certificates, if the certificates expire
after you uninstall MKE, the nodes in the swarm won’t be able to
communicate at all. To fix this, either reinstall MKE before the
certificates expire or disable swarm mode by running
docker swarm leave --force on every node.
Restore IP tables¶
When you install MKE, the Calico network plugin changes the host’s IP tables. When you uninstall MKE, the IP tables aren’t reverted to their previous state. After you uninstall MKE, restart the node to restore its IP tables.