Systemd Unit breaks Ignition without errors

Project Discussion
1

I use Ignition config and it worked fine.

{
  "ignition": {
    "version": "3.0.0"
  },
  "passwd": {
    "users": [
      {
        "groups": [
          "docker",
          "sudo"
        ],
        "name": "core",
        "sshAuthorizedKeys": [
          "ssh-rsa ...."
        ],
        "passwordHash": " ..."
      }
    ]
  },
  "storage": {
    "disks": [
      {
        "device": "/dev/sda",
        "wipeTable": true,
        "partitions": [
          {
            "label": "root1",
            "typeGuid": "be9067b9-ea49-4f15-b4f6-f36f8c9e1818"
          }
        ]
      },
      {
        "device": "/dev/sdb",
        "wipeTable": true,
        "partitions": [
          {
            "label": "root2",
            "typeGuid": "be9067b9-ea49-4f15-b4f6-f36f8c9e1818"
          }
        ]
      }
    ],
    "raid": [
      {
        "devices": [
          "/dev/sda1",
          "/dev/sdb1"
        ],
        "level": "raid1",
        "name": "root_array"
      }
    ],
    "filesystems": [{
      "device": "/dev/md/root_array",
      "path": "/var/lib/docker/volumes",
      "format": "ext4",
      "label": "DATA",
      "wipeFilesystem": true
    }],
    "files": [
      {
        "path": "/etc/hostname",
        "mode": 420,
        "contents": {
          "source": "data:,host1"
        }
      }
    ]
  }
}

I needed to add auto-mount option for my RAID array so /var/lib/docker/volumes is auto-mounted to the RAID array created by Ignition. I did it this way:

      "systemd": {
        "units": [
          {
            "contents": "[Unit]\nBefore=local-fs.target\n[Mount]\nWhere=/var/lib/docker/volumes\nWhat=/dev/md/root_array\n[Install]\nWantedBy=local-fs.target",
            "enabled": true,
            "name": "var.mount"
          }
        ]
      }

Now Ignition works without an error, but I cannot login to my instance after install. It says “Permission denied” with SSH key and not prompting for password without it. I use 2048 bit SSH key.

works without an error

This means I edit boot config and enable Ignition output to tty that usually gives useful errors.

2

The reason was naming of the unit file. It has to be “var-lib-docker-volumes.mount”, respective to the [Mount]Where= path to avoid systemd error “bad unit file setting” which was happening behind the scene here.