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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/best_practices_guide.adoc | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/docs/best_practices_guide.adoc b/docs/best_practices_guide.adoc index 08d95b2b8..6b744333c 100644 --- a/docs/best_practices_guide.adoc +++ b/docs/best_practices_guide.adoc @@ -466,3 +466,50 @@ If you want to use default with variables that evaluate to false you have to set In other words, normally the `default` filter will only replace the value if it's undefined. By setting the second parameter to `true`, it will also replace the value if it defaults to a false value in python, so None, empty list, empty string, etc. This is almost always more desirable than an empty list, string, etc. + +=== Yum and DNF +''' +[cols="2v,v"] +|=== +| **Rule** +| Package installation MUST use ansible action module to abstract away dnf/yum. +| Package installation MUST use name= and state=present rather than pkg= and state=installed respectively. +|=== +[cols="2v,v"] +|=== +| **Rule** +| Package installation MUST use name= and state=present rather than pkg= and state=installed respectively. +|=== + +This is done primarily because if you're registering the result of the +installation and you have two conditional tasks based on whether or not yum or +dnf are in use you'll end up inadvertently overwriting the value. It also +reduces duplication. name= and state=present are common between dnf and yum +modules. + +.Bad: +[source,yaml] +---- +--- +# tasks.yml +- name: Install etcd (for etcdctl) + yum: name=etcd state=latest" + when: "ansible_pkg_mgr == yum" + register: install_result + +- name: Install etcd (for etcdctl) + dnf: name=etcd state=latest" + when: "ansible_pkg_mgr == dnf" + register: install_result +---- + + +.Good: +[source,yaml] +---- +--- +# tasks.yml +- name: Install etcd (for etcdctl) + action: "{{ ansible_pkg_mgr }} name=etcd state=latest" + register: install_result + ---- |