How to re-run cloud-init without reboot

Question

I am using openstack to create a VM using 'nova boot' command. My image is cloud-init enabled. I pass a --user-data script which is a bash shell format for cloud-init to run during VM boot up time. All this happens successfully. Now my use-case is to re-run cloud-init to execute the same user-data script without rebooting the VM. I saw /usr/bin/cloud-init options and they do talk about running specific modules but nothing is able to make it execute the same user-data script. How can this be achieved ? Any help would be appreciated.

Solution 1

In order for cloud-init to reset, you need to execute rm -rf /var/lib/cloud/instances.

Then re run the cloud-init start and it will run the full boot script process again.

Solution 2

The commands have been updated so to re-run you need to clean out the existing config:

sudo cloud-init clean

Then re-run it using the init directive:

sudo cloud-init init

Beware: things like ssh host keys maybe regenerated.

Solution 3

Since this keeps popping up in search results, what works for me:

1. Delete semaphores in /var/lib/cloud/instances/i-xxxxxxx/sem. Cloud-init will not re-run if these files are present.

2. Edit /var/lib/cloud/instances/i-xxxxxxxx/scripts/part-001. This is your user-data script.

3. Execute only the user scripts module of cloud-init. This will not re-download user data but execute the already downloaded (and now, modified) script from step 2.

   sudo /usr/bin/cloud-init single -n cc_scripts_user

Solution 4

To run the packages module of cloud-config part of cloud-init, you can run

# cloud-init-cfg all config

To run the runcmd module of cloud-config part of cloud-init, you can run

# cloud-init-cfg all final

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