Amazon EC2 launch index

This configuration syntax can be provided to have a given set of cloud config data show up on a certain launch index (and not other launches). This is done by providing a key here which acts as a filter on the instance’s user data. When this key is absent (or non-integer) then the content of this file will always be used for all launch-indexes (i.e. the default behavior).

#cloud-config
launch-index: 5
# Upgrade the instance on first boot
# Default: false
package_upgrade: true

For further information on launch indexes, refer to the Amazon EC2 documentation.