ansible-role-k3s/documentation/operations/shrinking-a-cluster.md

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# Shrinking a cluster
This document describes the method for shrinking a cluster, by removing a
worker nodes.
## 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`
Currently your `inventory.yml` looks like this, it has three nodes defined,
`kube-0` (control node) and `kube-1`, `kube-2` (worker nodes).
```yaml
---
k3s_cluster:
hosts:
kube-0:
ansible_user: ansible
ansible_host: 10.10.9.2
ansible_python_interpreter: /usr/bin/python3
kube-1:
ansible_user: ansible
ansible_host: 10.10.9.3
ansible_python_interpreter: /usr/bin/python3
kube-2:
ansible_user: ansible
ansible_host: 10.10.9.4
ansible_python_interpreter: /usr/bin/python3
```
## Method
We have our three nodes, one control, two workers. The goal is to shrink this to
remove excess capacity by offboarding the worker node `kube-2`. To do this we
will set `kube-2` node to `k3s_state: uninstalled` in our inventory.
```yaml
---
k3s_cluster:
hosts:
kube-0:
ansible_user: ansible
ansible_host: 10.10.9.2
ansible_python_interpreter: /usr/bin/python3
kube-1:
ansible_user: ansible
ansible_host: 10.10.9.3
ansible_python_interpreter: /usr/bin/python3
kube-2:
ansible_user: ansible
ansible_host: 10.10.9.4
ansible_python_interpreter: /usr/bin/python3
k3s_state: uninstalled
```
What you will typically see is changes to your control plane (`kube-0`) and the
node being removed (`kube-2`). The role will register the removal of the node
with the cluster by draining the node and removing it from the cluster.
```text
PLAY RECAP *******************************************************************************************************
kube-0 : ok=55 changed=2 unreachable=0 failed=0 skipped=28 rescued=0 ignored=0
kube-1 : ok=40 changed=0 unreachable=0 failed=0 skipped=35 rescued=0 ignored=0
kube-2 : ok=23 changed=2 unreachable=0 failed=0 skipped=17 rescued=0 ignored=1
```