How to re-run
How to fully re-run cloud-init#
Most cloud-init configuration is only applied to the system once. This means that simply rebooting the system will only re-run a subset of cloud-init. Cloud-init provides two different options for re-running cloud-init for debugging purposes.
Making cloud-init run again may be destructive and must never be done on a production system. Artefacts such as ssh keys or passwords may be overwritten.
Remove the logs and cache, then reboot#
This method will reboot the system as if cloud-init never ran. This command does not remove all cloud-init artefacts from previous runs of cloud-init, but it will clean enough artefacts to allow cloud-init to think that it hasn’t run yet. It will then re-run after a reboot.
cloud-init clean --logs --reboot
Run a single cloud-init module#
If you are using user data cloud-config format, you might wish to re-run just a single configuration module. Cloud-init provides the ability to run a single module in isolation and separately from boot. This command is:
$ sudo cloud-init single --name cc_ssh --frequency always
Generating public/private ed25519 key pair
This subcommand is not called by the init system. It can be called manually to load the configured datasource and run a single cloud-config module once, using the cached user data and metadata after the instance has booted.
Each cloud-config module has a module
PER_ALWAYS. When a module is run by cloud-init, it stores a semaphore file in
/var/lib/cloud/instance/sem/config_<module_name>.<frequency> which marks when the module last successfully ran. Presence of this semaphore file prevents a module from running again if it has already been run.
cloud-init.log for output of what operations were performed as
How to partially re-run cloud-init#
If the behavior you are testing runs on every boot, there are a couple of ways to test this behavior.
Manually run cloud-init stages#
Note that during normal boot of cloud-init, the init system runs these stages at specific points during boot. This means that running the code manually after booting the system may cause the code to interact with the system in a different way than it does while it boots.
cloud-init init --local
cloud-init modules --mode=config
cloud-init modules --mode=final
Reboot the instance#
Rebooting the instance will take a little bit longer, however it will make cloud-init stages run at the correct times during boot, so it will behave more correctly.
reboot -h now