974 B
974 B
Provide user data to instances
User data is a blob of data that the user can specify when they launch an instance. The instance can access this data through the metadata service or config drive. Commonly used to pass a shell script that the instance runs on boot.
For example, one application that uses user data is the cloud-init system, which is an open-source package from Ubuntu that is available on various Linux distributions and which handles early initialization of a cloud instance.
You can place user data in a local file and pass it through the
--user-data <user-data-file>
parameter at instance
creation.
$ openstack server create --image ubuntu-cloudimage --flavor 1 \
--user-data mydata.file VM_INSTANCE
Note
The provided user data must be base64 encoded and is restricted to 65535 bytes.