cloud-init runcmd (using MAAS)

Question

I'm unable to run bash scripts in "runcmd:" that aren't inline.

runcmd:
    - [ bash, -c, echo "=========hello world=========" >>foo1.bar ]
    - [ bash, -c, echo "=========hello world=========" >>foo2.bar ]
    - [ bash, -c, /usr/local/bin/foo.sh ]

The first two lines are successfully run on the deployed Ubuntu instance. However, the foo.sh doesn't seem to run.

Here is /usr/local/bin/foo.sh:

#!/bin/bash
echo "=========hello world=========" >>foosh.bar

foo.sh has executable permissions for root and resides on the MAAS server.

I've looked at the following but they don't seem to sort out my issue:

What happens if you run that same command from the command line? — larsks, Feb 02 '22 at 01:15
@larsks If I run the command in the foo.sh on the deployed server/OS, it runs properly. — Jamaica-Jan, Feb 02 '22 at 20:56
But if you run the *same commandline* you have in your cloud-init configuration? `bash -c /usr/local/bin/foo.sh` — larsks, Feb 02 '22 at 20:59
Yes...It doesn't run because the file foo.sh isn't there. I was under the impression that cloud-init would take it from the "maas server node" and run it on the deployed machine...any idea how to resolve that? — Jamaica-Jan, Feb 03 '22 at 14:49

score 2 · Accepted Answer · answered Feb 03 '22 at 14:56

Anything you run using runcmd must already exist on the filesystem. There is no provision for automatically fetching something from a remote host.

You have several options for getting files there. Two that come to mind immediately are:

You could embed the script in your cloud-init configuration using the write-files directive:

write_files:
  - path: /usr/local/bin/foo.sh
    permissions: '0755'
    content: |
      #!/bin/bash
      echo "=========hello world=========" >>foosh.bar

runcmd:
  - [bash, /usr/local/bin/foo.sh]

You could fetch the script from a remote location using curl (or similar tool):

runcmd:
  - [curl, -o, /usr/local/bin/foo.sh, http://somewhere.example.com/foo.sh]
  - [bash, /usr/local/bin/foo.sh]

cloud-init runcmd (using MAAS)

1 Answers1