HowTo add, move (rename), or remove nodes¶

...or how to scale vertically. To replace the same node with a clean OS, remove it and add it again.

Add new nodes¶

Tip

You can add multiple nodes at the same time

Add its details to the inventory at the end of the group (masters or workers):

metal/inventories/prod.yml

diff --git a/metal/inventories/prod.yml b/metal/inventories/prod.yml
index 123456..abcdef 100644
--- a/metal/inventories/prod.yml
+++ b/metal/inventories/prod.yml
@@ -8,3 +8,4 @@ metal:
     nodes:
       hosts:
         foo: {ansible_host: 10.10.10.23, mac: '...', disk: nvme0n1, network_interface: eno1}
+        bar: {ansible_host: 10.10.10.24, mac: '...', disk: nvme0n1, network_interface: eno1}

Install the OS and join the cluster:

make metal

That's it!

Remove a node¶

Danger

It is highly recommended to remove nodes one at a time.

Remove it from the inventory:

metal/inventories/prod.yml

diff --git a/metal/inventories/prod.yml b/metal/inventories/prod.yml
index 123456..abcdef 100644
--- a/metal/inventories/prod.yml
+++ b/metal/inventories/prod.yml
@@ -8,3 +8,4 @@ metal:
     nodes:
       hosts:
         foo: {ansible_host: 10.10.10.23, mac: '...', disk: nvme0n1, network_interface: eno1}
-        bar: {ansible_host: 10.10.10.24, mac: '...', disk: nvme0n1, network_interface: eno1}

Drain the node:

kubectl drain ${NODE_NAME} --delete-emptydir-data --ignore-daemonsets --force

Remove the node from the cluster

kubectl delete node ${NODE_NAME}

Shutdown the node:

ssh root@${NODE_IP} poweroff

Tip

You can run make remove NODE_NAME=bar to achieve the above steps.
NB! this will also wipe the disk on the node!

Rename a node¶

Warning

Make sure to stop and remove ephemeral pxe docker containers before you re-run bootstrap: docker stop files-http-1 files-dnsmasq-1 && docker rm files-http-1 files-dnsmasq-1

First remove the node, then update the inventory file:

metal/inventories/prod.yml

diff --git a/metal/inventories/prod.yml b/metal/inventories/prod.yml
index 123456..abcdef 100644
--- a/metal/inventories/prod.yml
+++ b/metal/inventories/prod.yml
@@ -8,3 +8,4 @@ metal:
     nodes:
       hosts:
         foo: {ansible_host: 10.10.10.23, mac: '...', disk: nvme0n1, network_interface: eno1}
-        bar: {ansible_host: 10.10.10.24, mac: '...', disk: nvme0n1, network_interface: eno1}
+        baz: {ansible_host: 10.10.10.24, mac: '...', disk: nvme0n1, network_interface: eno1}

After that, install the OS and join the cluster:

make metal