Add systemd support

[Garrett Holmstrom]

Cloud-init is currently very upstart-specific. Adding support for systemd would help make it work on Fedora.

[Scott Moser (smoser)]

Garret, I pulled your systemd files from Fedora under revno 465.
If there is other work to do, let me know.

[Kevin Brackney (kbrackney)]

Installed Packages
Name : cloud-init
Arch : noarch
Version : 0.6.2
Release : 0.7.bzr457.fc16

Under Fedora 16, the systemd resource cloud-config.target is defined as requiring both cloud-init-local.service and cloud-init.service. If no local datastore is defined (as possibly in an EC2 deployment), the cloud-init-local.service exits with a non-zero return code causing a cascade of failures related to dependent services:

Feb 15 18:47:09 domU-12-31-39-00-85-B2 [CLOUDINIT] cloud-init[INFO]: cloud-init start-local running: Wed, 15 Feb 2012 23:47:09 +0000. up 9.73 seconds
Feb 15 18:47:09 domU-12-31-39-00-85-B2 [CLOUDINIT] __init__.py[DEBUG]: searching for data source in ['DataSourceNoCloud', 'DataSourceOVF']
Feb 15 18:47:09 domU-12-31-39-00-85-B2 [CLOUDINIT] __init__.py[DEBUG]: Did not find data source. searched classes: ['DataSourceNoCloud', 'DataSourceOVF']

Feb 15 18:47:09 domU-12-31-39-00-85-B2 systemd[1]: cloud-init-local.service: main process exited, code=exited, status=1
Feb 15 18:47:09 domU-12-31-39-00-85-B2 systemd[1]: Job cloud-final.service/start failed with result 'dependency'.
Feb 15 18:47:09 domU-12-31-39-00-85-B2 systemd[1]: Job cloud-config.service/start failed with result 'dependency'.
Feb 15 18:47:09 domU-12-31-39-00-85-B2 systemd[1]: Job cloud-config.target/start failed with result 'dependency'.
Feb 15 18:47:09 domU-12-31-39-00-85-B2 systemd[1]: Unit cloud-init-local.service entered failed state.

cloud-init-local.service - Initial cloud-init job (pre-networking)
          Loaded: loaded (/lib/systemd/system/cloud-init-local.service; enabled)
          Active: failed since Wed, 15 Feb 2012 18:57:58 -0500; 1h 8min ago
         Process: 374 ExecStart=/usr/bin/cloud-init start-local (code=exited, status=1/FAILURE)
          CGroup: name=systemd:/system/cloud-init-local.service

Suggest changing the /lib/systemd/system/cloud-config.target definition to remove the mandatory requirement on cloud-init-local.service and make it optional. This should then allow the instance to be configured appropriately from the cloud-providers metadata/userdata resource as the remaining services will be allowed to run.

[Garrett Holmstrom (gholms)]

Good catch, Kevin. cloud-init shouldn't be failing when no data source exists. That is fixed in bzr rev. 524.

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/2213