# defining package lists across roles **URL:** \ **Category:** Ansible Project\ **Created:** [August 13, 2013, 7:16pm UTC](https://forum.ansible.com/t/defining-package-lists-across-roles/13294 "2013-08-13T19:16:41Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Abhijit\_Menon-Sen2](https://avatars.discourse-cdn.com/v4/letter/a/ea5d25/32.png) [@Abhijit\_Menon-Sen2](https://forum.ansible.com/u/Abhijit_Menon-Sen2)\ **Post date:** [August 13, 2013, 7:16pm UTC](https://forum.ansible.com/t/defining-package-lists-across-roles/13294/1 "2013-08-13T19:16:41Z")
Hi. Another semi-related question arose while I was installing packages. I have roles named "smtp-server", "imap-server", and so on; and in each role I have a task that does essentially the same thing:     - apt: pkg=$item state=installed       with\_items: [foo, bar, …] Now, this works fine, but I started wondering if I could do this in one task[\*]. For example, I could have roles/common/tasks/packages.yml that does:     - apt: pkg=$item state=installed       with\_items: packages …where "packages" is a variable defined via vars/main.yml by each role:     - packages: [postfix, dovecot, …] This sounds good, but unfortunately, there's no way to append to the "packages" list in successive vars/main.yml files. As far as I can tell, the "hash\_behaviour=merge" setting doesn't really help here, because it merges only hashes, not lists. At the moment, the solution I've settled for is to remove \*all\* package installation from the individual roles, and just put the whole package list into roles/common/tasks/packages.yml. Obviously, this works, but it "would be nice" to have each role declare its dependencies. Can anyone suggest a neat way to do this or something like it? Each role should be able to declare packages it wants, but they should be combined into a single apt transaction somewhere. -- ams 1. One good reason to do this in one place is to not sprinkle handling    of policy-rc.d across tasks, but I can think of other reasons. And    at least one other person on IRC independently expressed a desire    to build up package lists in this way in the past few days. ---
**Author:** ![Michael\_DeHaan2](https://avatars.discourse-cdn.com/v4/letter/m/da6949/32.png) [@Michael\_DeHaan2](https://forum.ansible.com/u/Michael_DeHaan2)\ **Post date:** [August 14, 2013, 12:34am UTC](https://forum.ansible.com/t/defining-package-lists-across-roles/13294/2 "2013-08-14T00:34:22Z")
“This sounds good, but unfortunately, there’s no way to append to the “packages” list in successive vars/main.yml files.” This is true. You can add to hash variables if you configure the merging policy in ansible.cfg but you can’t append to variables. It would be fine to just have seperate apt statements that operate on the specific lists – invoking apt a few extra times should be fine. ---
**Author:** ![C\_Morgan\_Hamill](https://avatars.discourse-cdn.com/v4/letter/c/ebca7d/32.png) [@C\_Morgan\_Hamill](https://forum.ansible.com/u/C_Morgan_Hamill)\ **Post date:** [August 14, 2013, 1:09pm UTC](https://forum.ansible.com/t/defining-package-lists-across-roles/13294/3 "2013-08-14T13:09:08Z")
Excerpts from Michael DeHaan's message of 2013-08-13 20:34:22 -0400: > It would be fine to just have seperate apt statements that operate on the > specific lists -- invoking apt a few extra times should be fine. If you're really concerned with multiple transactions, you could do something like:     - apt: pkg={{item}} state=installed       with\_flattened:         - list\_of\_common\_packages         - list\_of\_role\_specific\_packages