How do detect that cloud-init completed initialization

Question

I am configuring an OpenStack box using cloud-init/cloud-config. I intend to wait until it is fully configured before I start using it.

This is not all that hard to do using some marker file or detecting if the cloud-init process is still running, though it seems quite cumbersome to do that in every cloud-init script. Is there some recommended way? Natively supported by cloud-init, ideally?

score 18 · Answer 1 · answered Aug 27 '21 at 13:20

The following command does the trick:

cloud-init status --wait

From https://ubuntu.com/blog/cloud-init-v-18-2-cli-subcommands:

cloud-init status gives simple human-readable or programmatic output for what cloud-init is doing and whether it has finished successfully. It can be used as a sanity check on a machine or in scripts to block until cloud-init has completed successfully.

Oliver Gondža · Answer 2 · 2023-07-24T06:47:37.410

6

Another alternative is to let the cloud-init phone home once it finishes:

phone_home:
    url: https://example.com/$INSTANCE_ID/
    post:
        - pub_key_dsa
        - instance_id
        - fqdn
    tries: 10

edited Jul 24 '23 at 06:47

answered Apr 19 '16 at 12:24

Oliver Gondža

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1

Sounds nice, link is dead. Prime example of why you need to include your answer here on SO. – kthy Jun 09 '22 at 13:50
1

Good point, I updated the answer. – Oliver Gondža Jun 10 '22 at 19:01

score 3 · Answer 3 · answered Feb 20 '16 at 07:02

3

As @flyxiao pointed out, cloud-init put status information into a dedicated directory on a filesystem: /run/cloud-init/ (preferred over /var/lib/cloud/data/ as it is guaranteed to describe last init process). status.json contains detailed about all init phases and result.json denotes the whole init is completed. The project documentation suggest a python script to detect cloud-init completion:

 fin = "/run/cloud-init/result.json"
 if os.path.exists(fin):

   ret = json.load(open(fin, "r"))

   if len(ret['v1']['errors']):

     print "Finished with errors:" + "\n".join(ret['v1']['errors'])

   else:

     print "Finished no errors"

 else:

   print "Not Finished"

answered Feb 20 '16 at 07:02

Oliver Gondža

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Thank you, very useful. Also needs to be checked that cloud-init is installed and enabled IMO :) .. in case somebody is using a mix of images with and without cloud-init. – akostadinov Mar 03 '16 at 13:11
Apparently, there is now a dedicated command for that - `cloud-init status`. More information is available [here](https://ubuntu.com/blog/cloud-init-v-18-2-cli-subcommands). – Alexander Kucheryuk Jun 16 '20 at 10:42

score 3 · Answer 4 · answered Jul 15 '17 at 02:15

3

The simplest answer is to set a tag on the instance so you can poll for its existence.

If you have a Linux host, do this last:

aws ec2 create-tags --resources `ec2metadata --instance-id` --tags Key=BootstrapStatus,Value=complete

This avoids needing to set up a network endpoint, creating a point of failure, or SSHing in, creating a need to secure credentials.

answered Jul 15 '17 at 02:15

Michael Labbé

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Right, though it require cloud-init assistance and the machine able to talk to cloud provider. – Oliver Gondža Jul 16 '17 at 09:03

score 2 · Answer 5 · edited Feb 19 '16 at 10:21

2

You can check the /var/lib/cloud/data/status.json for cloud-init status. Or if the host is using upstart, add one init process in /etc/init/newprocess.conf and newprocess.conf should be started after cloud-final.

edited Feb 19 '16 at 10:21

Oliver Gondža

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answered Feb 18 '16 at 08:58

flyxiao

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I am using cloud-init 0.7.6 on RHEL and there is no `newprocess.conf` file. Can you provide documentation link? I will have a look at `/var/lib/cloud/data/*.json`. – Oliver Gondža Feb 18 '16 at 11:43
Maybe /var/lib/cloud/data/*.json matches you, i need clear newprocess.conf solution. If your RHEL uses the upstart as the OS init, you may change /etc/init/cloud-init-local.conf (remove one temp file), /etc/init/cloud-final.conf (generate one temp file). if your RHEL uses the systemd as the OS init. Change cloud-init-local.service and cloud-final.service. – flyxiao Feb 19 '16 at 06:47

How do detect that cloud-init completed initialization

5 Answers5