homeserver/roles/xanmanning.k3s/documentation/operations/stop-start-cluster.md

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# Stopping and Starting a cluster
This document describes the Ansible method for restarting a k3s cluster
deployed by this role.
## Assumptions
It is assumed that you have already deployed a k3s cluster using this role,
you have an appropriately configured inventory and playbook to create the
cluster.
Below, our example inventory and playbook are as follows:
- inventory: `inventory.yml`
- playbook: `cluster.yml`
## Method
### Start cluster
You can start the cluster using either of the following commands:
- Using the playbook: `ansible-playbook -i inventory.yml cluster.yml --become -e 'k3s_state=started'`
- Using an ad-hoc command: `ansible -i inventory.yml -m service -a 'name=k3s state=started' --become all`
Below is example output, remember that Ansible is idempotent so re-running a
command may not necessarily change the state.
**Playbook method output**:
```text
PLAY RECAP *******************************************************************************************************
kube-0 : ok=6 changed=0 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
kube-1 : ok=6 changed=0 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
kube-2 : ok=6 changed=0 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
```
### Stop cluster
You can stop the cluster using either of the following commands:
- Using the playbook: `ansible-playbook -i inventory.yml cluster.yml --become -e 'k3s_state=stopped'`
- Using an ad-hoc command: `ansible -i inventory.yml -m service -a 'name=k3s state=stopped' --become all`
Below is example output, remember that Ansible is idempotent so re-running a
command may not necessarily change the state.
**Playbook method output**:
```text
PLAY RECAP *******************************************************************************************************
kube-0 : ok=6 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
kube-1 : ok=6 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
kube-2 : ok=6 changed=1 unreachable=0 failed=0 skipped=2 rescued=0 ignored=0
```
### Restart cluster
Just like the `service` module, you can also specify `restarted` as a state.
This will do `stop` followed by `start`.
- Using the playbook: `ansible-playbook -i inventory.yml cluster.yml --become -e 'k3s_state=restarted'`
- Using an ad-hoc command: `ansible -i inventory.yml -m service -a 'name=k3s state=restarted' --become all`
```text
PLAY RECAP *******************************************************************************************************
kube-0 : ok=7 changed=1 unreachable=0 failed=0 skipped=3 rescued=0 ignored=0
kube-1 : ok=7 changed=1 unreachable=0 failed=0 skipped=3 rescued=0 ignored=0
kube-2 : ok=7 changed=1 unreachable=0 failed=0 skipped=3 rescued=0 ignored=0
```
## Tips
You can limit the targets by adding the `-l` flag to your `ansible-playbook`
command, or simply target your ad-hoc commands. For example, in a 3 node
cluster (called `kube-0`, `kube-1` and `kube-2`) we can limit the restart to
`kube-1` and `kube-2` with the following:
- Using the playbook: `ansible-playbook -i inventory.yml cluster.yml --become -e 'k3s_state=restarted' -l "kube-1,kube-2"`
- Using an ad-hoc command: `ansible -i inventory.yml -m service -a 'name=k3s state=restarted' --become "kube-1,kube-2"`
```text
PLAY RECAP ********************************************************************************************************
kube-1 : ok=7 changed=2 unreachable=0 failed=0 skipped=3 rescued=0 ignored=0
kube-2 : ok=7 changed=2 unreachable=0 failed=0 skipped=3 rescued=0 ignored=0
```
## FAQ
1. _Why might I use the `ansible-playbook` command over an ad-hoc command?_
- The stop/start tasks will be aware of configuration. As the role
develops, there might be some pre-tasks added to change how a cluster
is stopped or started.