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https://github.com/PyratLabs/ansible-role-k3s
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74 lines
2.3 KiB
Markdown
74 lines
2.3 KiB
Markdown
# Shrinking a cluster
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This document describes the method for shrinking a cluster, by removing a
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worker nodes.
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## Assumptions
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It is assumed that you have already deployed a k3s cluster using this role,
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you have an appropriately configured inventory and playbook to create the
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cluster.
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Below, our example inventory and playbook are as follows:
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- inventory: `inventory.yml`
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- playbook: `cluster.yml`
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Currently your `inventory.yml` looks like this, it has three nodes defined,
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`kube-0` (control node) and `kube-1`, `kube-2` (worker nodes).
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```yaml
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---
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k3s_cluster:
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hosts:
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kube-0:
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ansible_user: ansible
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ansible_host: 10.10.9.2
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ansible_python_interpreter: /usr/bin/python3
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kube-1:
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ansible_user: ansible
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ansible_host: 10.10.9.3
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ansible_python_interpreter: /usr/bin/python3
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kube-2:
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ansible_user: ansible
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ansible_host: 10.10.9.4
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ansible_python_interpreter: /usr/bin/python3
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```
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## Method
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We have our three nodes, one control, two workers. The goal is to shrink this to
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remove excess capacity by offboarding the worker node `kube-2`. To do this we
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will set `kube-2` node to `k3s_state: uninstalled` in our inventory.
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```yaml
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---
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k3s_cluster:
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hosts:
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kube-0:
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ansible_user: ansible
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ansible_host: 10.10.9.2
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ansible_python_interpreter: /usr/bin/python3
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kube-1:
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ansible_user: ansible
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ansible_host: 10.10.9.3
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ansible_python_interpreter: /usr/bin/python3
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kube-2:
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ansible_user: ansible
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ansible_host: 10.10.9.4
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ansible_python_interpreter: /usr/bin/python3
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k3s_state: uninstalled
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```
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What you will typically see is changes to your control plane (`kube-0`) and the
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node being removed (`kube-2`). The role will register the removal of the node
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with the cluster by draining the node and removing it from the cluster.
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```text
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PLAY RECAP *******************************************************************************************************
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kube-0 : ok=55 changed=2 unreachable=0 failed=0 skipped=28 rescued=0 ignored=0
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kube-1 : ok=40 changed=0 unreachable=0 failed=0 skipped=35 rescued=0 ignored=0
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kube-2 : ok=23 changed=2 unreachable=0 failed=0 skipped=17 rescued=0 ignored=1
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```
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