Complex data types with nested lists

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1

We have a role that defines user accounts as follows:

users:

  • username: user1
    comment: User 1
    uid: 3001
    ssh_key: “xxx”

  • username: user2
    comment: User 2
    uid: 3002
    ssh_key: “yyy”

Users are then grouped by name into other lists:

regular_users:

  • user1
  • user2
    …

ops_users:

  • user3
  • user4
    …

Our hosts then have a fact called user_roles that’s a list of each group of users and individual usernames to create accounts for. We then have tasks defined like this:

  • name: add users
    user: name={{ item.username }}
    comment=“{{ item.comment }}”
    uid={{ item.uid }}
    when: item.username in lookup(‘flattened’,user_roles)

with_items: users

  • name: add SSH keys
    authorized_key: user={{ item.username }}
    key=“{{ item.ssh_key }}”
    when: item.username in lookup(‘flattened’,user_roles) and item.ssh_key is defined
    with_items: users

All of this is working great. We’re managing about 50 different user accounts over 80 servers in varying groups without any difficulty. But now I’d like to be able to extend this to support multiple SSH keys for each user. So I’d like to be able to define a user along these lines:

  • username: userFoo
    comment: User Foo
    uid: 4321
    ssh_keys: [ ‘xxx’, ‘yyy’, ‘zzz’]

But if I do this then I’m at a complete loss of how to rewrite the authorized_key task to handle it properly. At first glance I would expect that I’d need to use with_nested but I’m not entirely sure how to go about doing it. I tried variations of this, but haven’t gotten anything to work:

  • name: add multiple SSH keys
    authorized_key: user={{ item[0].username }}
    key=“{{ item.[1] }}”
    when: item[0].username in lookup(‘flattened’,user_roles) and item[0].ssh_keys is defined
    with_nested:
  • users
  • item[0].ssh_keys

Is there a better way of managing a dynamic list of ssh keys? Or am I just trying something that’s too complex for Ansible to handle cleanly?

-Bruce

2

I’d recommend storing you keys in files, and using lookup(‘file’, …)

The. You can store multiple keys in a single file.

Additionally you could just store multiple keys as a string with new lines in your current data structure and not try using a list.

3

Ah, thanks! All the documentation for the authorized_key module implies that it works on just one key at a time, not a file/string that contains multiple keys. That documentation should really be updated…

-Bruce

4

Patches would be accepted! :slight_smile:

5

You can store multiple keys in a single file, but that means that you would have to manually create a separate file for each key combination you want to deploy. Instead, take a look at my pull request for with_nested () and the example I have given in my previous post at the “Nested looping with hash/dict so I can override values” thread. It would allow you to do what you want more cleanly.

6

If you specify user SSH keys as a list of keys, you can use them like this using with_subelements:

- name: User SSH keys
authorized_key: user="{{ item.0.username }}" key="{{ item.1 }}"
when: item.0.username in users_add
with_subelements:
- users
- ssh_key

This works for me without a problem. Just modify the when: condition to be like your one.