Amazon EC2

The EC2 datasource is the oldest and most widely used datasource that cloud-init supports. This datasource interacts with a magic ip that is provided to the instance by the cloud provider. Typically this ip is 169.254.169.254 of which at this ip a http server is provided to the instance so that the instance can make calls to get instance userdata and instance metadata.

Metadata is accessible via the following URL:

GET http://169.254.169.254/2009-04-04/meta-data/
ami-id
ami-launch-index
ami-manifest-path
block-device-mapping/
hostname
instance-id
instance-type
local-hostname
local-ipv4
placement/
public-hostname
public-ipv4
public-keys/
reservation-id
security-groups

Userdata is accessible via the following URL:

GET http://169.254.169.254/2009-04-04/user-data
1234,fred,reboot,true | 4512,jimbo, | 173,,,

Note that there are multiple versions of this data provided, cloud-init by default uses 2009-04-04 but newer versions can be supported with relative ease (newer versions have more data exposed, while maintaining backward compatibility with the previous versions).

To see which versions are supported from your cloud provider use the following URL:

GET http://169.254.169.254/
1.0
2007-01-19
2007-03-01
2007-08-29
2007-10-10
2007-12-15
2008-02-01
2008-09-01
2009-04-04
...
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