Machine Config

Machine Config Operator Documentation

Creating a Machine Configuration File

1. Base64 encode the content for inclusion in a MachineConfig:

   echo -n "mysecretvalue" | base64
   

2. Place the encoded value after base64, in the MachineConfig:

   apiVersion: machineconfiguration.openshift.io/v1
   kind: MachineConfig
   metadata:
     name: 99-worker-example
     labels:
       machineconfiguration.openshift.io/role: worker
   spec:
     config:
       ignition:
         version: 3.5.0
       storage:
         files:
         - path: /etc/file.conf
           mode: 0644
           overwrite: true
           contents:
             source: data:text/plain;charset=utf-8;base64,bXlzZWNyZXR2YWx1ZQ==
   

3. Apply:

   oc apply -f 99-worker-example.yaml
   

Use a File

base64 -w0 myfile.txt

CONTENT=$(base64 -w0 /path/to/myfile.conf)

cat <<EOF
apiVersion: machineconfiguration.openshift.io/v1
kind: MachineConfig
metadata:
  labels:
    machineconfiguration.openshift.io/role: worker
  name: 99-worker-myfile
spec:
  config:
    ignition:
      version: 3.5.0
    storage:
      files:
      - path: /etc/myfile.conf
        mode: 0644
        overwrite: true
        contents:
          source: data:text/plain;base64,${CONTENT}
EOF

To decode/verify:

echo "$CONTENT" | base64 -d

Creating a Machine Configuration File with Butane

Butane transpiles human-readable configs into MachineConfig resources, avoiding manual base64 encoding.

1. Install Butane:

   curl -LO https://mirror.openshift.com/pub/openshift-v4/clients/butane/latest/butane
   chmod +x butane
   sudo mv butane /usr/local/bin/
   

2. Write a Butane config — create 99-worker-example.bu:

   variant: openshift
   version: 4.22.0
   metadata:
     name: 99-worker-example
     labels:
       machineconfiguration.openshift.io/role: worker
   storage:
       files:
         - path: /etc/file.conf
           mode: 0644
           overwrite: true
           contents:
             inline: |
               mysecretvalue
   

3. Transpile to MachineConfig:

   butane 99-worker-example.bu -o 99-worker-example.yaml
   

4. Apply:

   oc apply -f 99-worker-example.yaml
   

Using a Local File

Instead of inline, reference a local file:

variant: openshift
version: 4.22.0
metadata:
  name: 99-worker-example
  labels:
    machineconfiguration.openshift.io/role: worker
storage:
  files:
    - path: /etc/file.conf
      mode: 0644
      overwrite: true
      contents:
        local: file.conf

butane 99-worker-example.bu --files-dir . -o 99-worker-example.yaml