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If you want to decrease the number of nodes, what happens depends on your chose COE. If you're running k8s, magnum will try to find a node with no running containers and delete them. If no empty nodes are found, magnum will warn you, and delete a node at random. With docker swarm, magnum have no logic to discover an empty node, and will just delete nodes at random.
Troubleshooting
Debugging an uhealthy cluster
To check status of a cluster
| Code Block |
|---|
$ heat stack-list -n
# Get the id of the cluster
$ openstack stack failure list <id of the cluster>
# OR
$ openstack coe cluster list
# Get the id of the cluster, NB, it's shorter than the heat ID
$ openstack coe cluster show <cluster ID> |
Debugging a part of the cluster
Use heat to find the id's of the cluster
| Code Block |
|---|
$ heat stack-list -n
<snip output>
$ heat resource-list <id from list above>
<snip output> |
Run a check of the cluster
| Code Block |
|---|
$ openstack stack check <ID from heat stack-list -n> |
Scaling down cluster when status is unhealthy
When scaling up the cluster beyond quota limit, the openstack coe cluster update command doesn't work. But resize does
| Code Block |
|---|
$ openstack coe cluster resize <your-cluster> <N> |
Upgrading
TBA