mirror of
https://github.com/PyratLabs/ansible-role-k3s
synced 2024-11-05 21:33:30 +01:00
75 lines
2.3 KiB
Markdown
75 lines
2.3 KiB
Markdown
|
# 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
|
||
|
|
```
|