###Ubuntu 16.04 (systemd)

Stage-1
---------
chkconfig cloud-init-local on 
Before=shutdown.target multi-user.target cloud-config.target cloud-init.service
After=local-fs.target systemd-journald.socket basic.target system.slice

Stage-2
---------
chkconfig cloud-init on 
Before=multi-user.target shutdown.target systemd-user-sessions.service cloud-config.target sshd-keygen.service ssh.service
After=network-online.target basic.target cloud-init-local.service system.slice systemd-journald.socket local-fs.target

Stage-3
---------
chkconfig cloud-config on
Before=cloud-final.service multi-user.target shutdown.target
After=systemd-journald.socket network-online.target syslog.target system.slice basic.target cloud-config.target

Stage-4
---------
chkconfig cloud-final on 
Before=multi-user.target shutdown.target
After=rc-local.service network-online.target cloud-config.service basic.target system.slice systemd-journald.socket syslog.target


###Ubuntu 14.04 (upstart)

Stage-1
---------
/etc/init/cloud-init-local.conf
start on mounted MOUNTPOINT=/

Stage-2
---------
/etc/init/cloud-init.conf
start on mounted MOUNTPOINT=/ and stopped cloud-init-nonet (After network is up)

Stage-3
---------
/etc/init/cloud-config.conf
tart on (filesystem and started rsyslog)

Stage-4
---------
/etc/init/cloud-final.conf
start on (stopped rc RUNLEVEL=[2345] and stopped cloud-config) (after rc.local)


###Execute Cloud-Init Manually

Stage-1
---------
cloud-init init --local

Stage-2
---------
cloud-init init

Stage-3
---------
cloud-init modules --mode=config

Stage-4
---------
cloud-init modules --mode=final


###Data Sources

Stage-1
---------
NoCloud Data Source

Look for local data here:
/var/lib/cloud/seed/nocloud/{meta-data,user-data,network-data,vendor-data}

If present, copy to /var/lib/cloud/instances/<instance_id>

* Will also attempt to mount vfat or iso device with LABEL="cidata" (if attached)
and copy data:
mount /dev/sr0 (or /dev/sdb, etc) /tmp
cp /tmp/{meta-data,user-data,network-data,vendor-data} /var/lib/cloud/instances/<instance_id>/*

Stage-2
---------
cat /etc/cloud/cloud.cfg.d/90_dpkg.cfg
datasource_list: [ NoCloud, ConfigDrive, OpenNebula, Azure, AltCloud, OVF, MAAS, GCE, OpenStack, CloudSigma, Ec2, CloudStack, None ]

* By default, first datasource listed is the priority. If metadata is discovered, it is ccopied to /var/lib/cloud/instances/<instance_id>/*

* All python modules listed in init stage (/etc/cloud/cloud.cfg) will execute.

Stage-3
---------
* All python modules listed in config stage (/etc/cloud/cloud.cfg) will execute.

Stage-4
---------
* All python modules listed in final stage (/etc/cloud/cloud.cfg) will execute.

###Cirros-init info

Commands
---------
cirros-apply
cirros-ds
cirros-per
cirros-query
cirros-status
cirros-userdata

Data Source List
------------------
cat /etc/cirros-init/config


Re-execute User-Data
----------------------
sudo rm -rf /var/lib/cirros/
sudo cirros-userdata