...
- Check if one or more of the instances have ok network. (ping). Some instances might have security groups making checking them impossible.
- Check if there are no more than 1 kube master on a compute node. They require quorum, so moving a master is needed if there are two instances of the same master on one compute node
Reboot the compute node when all is ok and verify that the compute node comes up, the instances are all active and the instances tested with ping still have network.
Continue to reboot one and one node checking each compute node as described above.