Add KubeVirt support

[rmohr]

KubeVirt is openstack config-drive compatible and uses the config-2 label (lower case).

xref coreos/fedora-coreos-tracker#1126

Testing ignition on a fcos machine where kubevirt injected the user-data shows this:

[core@vmi-fedora ~]$ sudo  /home/core/ignition --platform kubevirt --config-cache ignition.json --state-file state --stage fetch --log-to-stdout
INFO     : Ignition v2.13.0-58-g45429023
INFO     : Stage: fetch
INFO     : no config dir at "/usr/lib/ignition/base.d"
INFO     : no config dir at "/usr/lib/ignition/base.platform.d/kubevirt"
DEBUG    : parsed url from cmdline: ""
INFO     : no config URL provided
INFO     : reading system config file "/usr/lib/ignition/user.ign"
INFO     : no config at "/usr/lib/ignition/user.ign"
DEBUG    : creating temporary mount point
INFO     : op(1): [started]  mounting config drive
DEBUG    : op(1): executing: "mount" "-o" "ro" "-t" "auto" "/dev/disk/by-label/config-2" "/tmp/ignition-configdrive749859965"
INFO     : op(1): [finished] mounting config drive
INFO     : op(2): [started]  unmounting "/dev/disk/by-label/config-2" at "/tmp/ignition-configdrive749859965"
INFO     : op(2): [finished] unmounting "/dev/disk/by-label/config-2" at "/tmp/ignition-configdrive749859965"
DEBUG    : parsing config with SHA512: afca8c4e75ad3338fa48aa686c7bcc33973e6731e793e819d85950a41dfdd7d7b5dde42580ffbcc3bb3b76b9f9d7b438858b1e19380d3cb4a71d807f0823e20e
INFO     : fetch: fetch complete
INFO     : fetch: fetch passed
INFO     : Ignition finished successfully
[core@vmi-fedora ~]$ sudo cat ignition.json 
{"ignition":{"config":{"replace":{"verification":{}}},"proxy":{},"security":{"tls":{}},"timeouts":{},"version":"3.4.0-experimental"},"kernelArguments":{},"passwd":{"users":[{"name":"core","sshAuthorizedKeys":["ssh-rsa AAAAB3N..."]}]},"storage":{},"systemd":{}}
[core@vmi-fedora ~]$ sudo cat state
{"fetchedConfigs":[{"kind":"base","source":"system","referenced":false},{"kind":"base","source":"system","referenced":false},{"kind":"user","source":"kubevirt","referenced":false}],"luksPersistKeyFiles":null,"notatedDirectories":null}

If no user-data is present:

[core@vmi-fedora ~]$ sudo  /home/core/ignition --platform kubevirt --config-cache ignition.json --state-file state --stage fetch --log-to-stdout
INFO     : Ignition v2.13.0-58-g45429023-dirty
INFO     : Stage: fetch
INFO     : no config dir at "/usr/lib/ignition/base.d"
INFO     : no config dir at "/usr/lib/ignition/base.platform.d/kubevirt"
DEBUG    : parsed url from cmdline: ""
INFO     : no config URL provided
INFO     : reading system config file "/usr/lib/ignition/user.ign"
INFO     : no config at "/usr/lib/ignition/user.ign"
DEBUG    : creating temporary mount point
INFO     : op(1): [started]  mounting config drive
DEBUG    : op(1): executing: "mount" "-o" "ro" "-t" "auto" "/dev/disk/by-label/config-2" "/tmp/ignition-configdrive826956530"
INFO     : op(1): [finished] mounting config drive
INFO     : op(2): [started]  unmounting "/dev/disk/by-label/config-2" at "/tmp/ignition-configdrive826956530"
INFO     : op(2): [finished] unmounting "/dev/disk/by-label/config-2" at "/tmp/ignition-configdrive826956530"
DEBUG    : parsing config with SHA512: cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0ff8318d2877eec2f63b931bd47417a81a538327af927da3e
INFO     : not a config (empty): provider config was empty, continuing with empty cache config
INFO     : fetch: fetch complete
INFO     : fetch: fetch passed
INFO     : Ignition finished successfully
[core@vmi-fedora ~]$ sudo cat ignition.json 
{"ignition":{"config":{"replace":{"verification":{}}},"proxy":{},"security":{"tls":{}},"timeouts":{},"version":"3.4.0-experimental"},"kernelArguments":{},"passwd":{},"storage":{},"systemd":{}}[core@vmi-fedora ~]$ 
[core@vmi-fedora ~]$ sudo cat state 
{"fetchedConfigs":[{"kind":"base","source":"system","referenced":false}],"luksPersistKeyFiles":null,"notatedDirectories":null}

If no config-drive is present it just waits forever:

[core@vmi-fedora ~]$ sudo  /home/core/ignition --platform kubevirt --config-cache ignition.json --state-file state --stage fetch --log-to-stdout
INFO     : Ignition v2.13.0-58-g45429023-dirty
INFO     : Stage: fetch
INFO     : no config dir at "/usr/lib/ignition/base.d"
INFO     : no config dir at "/usr/lib/ignition/base.platform.d/kubevirt"
DEBUG    : parsed url from cmdline: ""
INFO     : no config URL provided
INFO     : reading system config file "/usr/lib/ignition/user.ign"
INFO     : no config at "/usr/lib/ignition/user.ign"
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...
DEBUG    : config drive ("/dev/disk/by-label/config-2") not found. Waiting...

[rmohr]

/cc @bgilbert

[bgilbert]

LGTM generally.

[bgilbert]

You'll need to rebase to pick up changes in the list of CI jobs.

[bgilbert]

Looks good!