Updating an IAM cert

We uploaded an IAM cert to AWS, and now need to update the certificate
(the contents). On the theory that a lost of this stuff is idempotent, I
thought this task, which we used to upload it in the first place, would
work to update it as well:

  - name: configure IAM certificates
    iam_cert:
      name: "{{ item }}"
      state: present
      cert: "{{ iam_cert[item]['certfile'] }}"
      key: "{{ iam_cert[item]['keyfile'] }}"
      cert_chain: "{{ iam_cert[item]['chainfile'] }}"
    with_items: "{{ iam_cert_names }}"

We've got a dict iam_cert in inventory, like this:

    iam_cert:
      myserver1:
        certfile: "/path/to/myserver1.crt"
        chainfile: "/path/to/myca.crt"
        keyfile: "/path/to/myserver1.key"

(and so on for myserver2 etc)

So this works fine for adding a new cert, but if we put a new cert in
/path/to/myserver.crt, it fails, saying:

  failed: [localhost] (item=myserver1) => {"changed": false, "failed": true, "item": "myserver1", "msg": "A cert with the name myserver1 already exists and has a different certificate body associated with it. Certificates cannot have the same name"}

https://docs.ansible.com/ansible/iam_cert_module.html has 'new_path',
which says "When present, this will update the path of the cert with the
value passed here.", but it doesn't say what this is supposed to be -- a
Boolean? a path to the new cert file on disk? Perhaps the same sort of
thing as the 'path' option, which says "When creating or updating, specify
the desired path of the certificate", but we're not using that, we're
using 'cert', which says "The path to the certificate body in PEM encoded
format." What's "the path of the certificate", and is it different from
"the path to the certificate body"? There's only one example, and it
doesn't use either 'path' or 'new_path'.

Anyone know how this is supposed to work?

                                      -Josh (jbs@care.com)

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I’m also wondering how this works. The documentation is often confusing about what exactly it means.

I’m seeing “already exists and has a different certificate body”, which I’m guessing is related to the error described here.