flatcar+k3s cloud-init

cloud-config.yaml

#cloud-config

coreos:
  units:
    - name: install-opt-dir.service
      content: |
        [Unit]
        Description=Install /opt directories
        ConditionPathIsDirectory=!/opt/libexec
        ConditionPathIsDirectory=!/opt/libexec.wd
        
        [Service]
        Type=oneshot
        ExecStart=/usr/bin/mkdir -p /opt/libexec /opt/libexec.wd
        
        [Install]
        WantedBy=multi-user.target
    - name: usr-libexec.mount
      content: |
        [Unit]
        Description=Allow k8s CNI plugins to be installed
        Before=local-fs.target
        Requires=install-opt-dir.service
        ConditionPathExists=/opt/libexec
        ConditionPathExists=/opt/libexec.wd
        
        [Mount]
        Type=overlay
        What=overlay
        Where=/usr/libexec
        Options=lowerdir=/usr/libexec,upperdir=/opt/libexec,workdir=/opt/libexec.wd
        
        [Install]
        WantedBy=local-fs.target
    - name: install-k3s.service
      command: start
      content: |
        [Unit]
        Description=Install k3s
        Requires=usr-libexec.mount
        ConditionPathExists=!/etc/.k3s-installed
        
        [Service]
        Type=oneshot
        Environment=INSTALL_K3S_BIN_DIR=/opt/bin INSTALL_K3S_SELINUX_WARN=true INSTALL_K3S_CHANNEL=latest
        ExecStart=/usr/bin/mkdir -p /opt/bin
        ExecStart=/usr/bin/curl -sfSL -o /tmp/k3s.sh https://get.k3s.io
        ExecStart=/usr/bin/chmod +x /tmp/k3s.sh
        ExecStart=/tmp/k3s.sh
        ExecStart=/usr/bin/touch /etc/.k3s-installed
        
        [Install]
        WantedBy=multi-user.target
ssh_authorized_keys:
  - <SSH_KEY>
hostname: flatcar-k3s-00

@frezbo oh nice. Since it is a oneshot that is pulled in by dependency of usr-libexec.mount I didn't find that [Install] was needed. Did this config not work for you without that section?

@vbatts I was using the ignition config and it failed to create the unit. If you want I can spin a vm and show the logs with [Install] section missing. This was with FlatCar Linux on DigitalOcean.

IgnitionConfig:

{
  "ignition": {
    "version": "2.1.0"
  },
  "systemd": {
    "units": [
      {
        "name": "install-opt-dir.service",
        "enabled": true,
        "contents": "[Unit]\n\tDescription=Install /opt directories\n\tConditionPathIsDirectory=!/opt/libexec\n\tConditionPathIsDirectory=!/opt/libexec.wd\n\n[Service]\n\tType=oneshot\n\tExecStart=/usr/bin/mkdir -p /opt/libexec /opt/libexec.wd\n\"
      }
    ]
  }
}

@frezbo 👍 no worries. And thanks for the ignition example!