How to compare kernel (or other) version numbers in Ansible

Question

For a role I'm developing I need to verify that the kernel version is greater than a particular version.

I've found the ansible_kernel fact, but is there an easy way to compare this to other versions? I thought I might manually explode the version string on the .'s and compare the numbers, but I can't even find a friendly filter to explode the version string out, so I'm at a loss.

for splitting, since ansible 2.0, you can `{{ variable.split('.') }}`; you can then use a loop using `with_together` to compare major, minor and patch version each other — guido, Sep 29 '16 at 21:56

score 40 · Accepted Answer · edited Apr 20 '21 at 13:48

40

There is a test for it:

{{ ansible_distribution_version is version('12.04', '>=') }}

{{ sample_version_var is version('1.0', operator='lt', strict=True) }}

edited Apr 20 '21 at 13:48

Bert Peters

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answered Sep 30 '16 at 06:24

Konstantin Suvorov

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Thanks @konstantin-suvorov. I've now found the docs on this, but can't see find an explanation of what 'strict' does. Do you know where I can find this info? – TobyG Oct 03 '16 at 10:36
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See [this](http://stackoverflow.com/a/11887885/2795592) answer about StrictVersion vs LooseVersion. – Konstantin Suvorov Oct 03 '16 at 11:07
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FYI, in Ansible 2.5 version_compare was renamed to version. – James Nov 06 '20 at 09:04

score 7 · Answer 2 · answered Mar 05 '19 at 06:58

7

To Print the host IP address if the kernel version is less than 3

Ansible Version : 2.0.0.2

---
- hosts: all
  vars:
   kernel_version: "{{ ansible_kernel }}"
  tasks:
   - name: 'kernel version from facts'
     debug:
      msg: '{{ansible_all_ipv4_addresses}} {{ansible_kernel}}'
     when: ansible_kernel |  version_compare('3','<')

**

In 2.5 version_compare was renamed to version

**

answered Mar 05 '19 at 06:58

Fuji Komalan

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Though this is a late response, I feel as though this is the better answer. Can you edit your answer to include a link to the documentation as @konstantin-suvorov did to make the best answer? – Cody B Apr 18 '19 at 15:25
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version isn't a filter at least in ansible 2.9, see usage at https://github.com/systemli/ansible-role-sshd/pull/24/files – timfeirg Dec 28 '19 at 14:26

score 5 · Answer 3 · answered Dec 23 '20 at 17:27

For ansible>=2.9 this won't work, as the test syntax is now strictly separated from filters.

https://docs.ansible.com/ansible/latest/user_guide/playbooks_tests.html

The working solution would be:

{{ sample_version_var is version('1.0', operator='lt', strict=True) }}
...

score 0 · Answer 4 · answered Dec 23 '22 at 19:16

To compare a version number, such as checking if the ansible_facts['distribution_version'] version is greater than or equal to ‘12.04’, you can use the version test.

{{ ansible_facts['distribution_version'] is version('12.04', '>=') }}

When using version in a playbook or role, don’t use {{ }} as described in the FAQ

vars:
    my_version: 1.2.3

tasks:
    - debug:
        msg: "my_version is higher than 1.0.0"
      when: my_version is version('1.0.0', '>')

Check Ansible Doc for more info

score -4 · Answer 5 · edited Apr 08 '17 at 09:59

-4

Have you thought of using shell module instead? for example:

   - name: Get Kernel version
     shell: uname -r | egrep '^[0-9]*\.[0-9]*' -o
     register: kernel_shell_output

   - debug: msg="{{ kernel_shell_output.stdout}}"

   - name: Add cstate and reboot bios if kernel is 4.8
     shell: echo "do what yo need to do"
     when: kernel_shell_output.stdout == "4.8"

edited Apr 08 '17 at 09:59

brunorey

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answered Sep 29 '16 at 21:22

sebastienvg

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Using shell instead of modules is ansible anti-pattern. – Konstantin Suvorov Sep 30 '16 at 06:25
Also, won't comparing strings not necessarily place the version in the correct order? (I've not tests this) – TobyG Oct 03 '16 at 10:31
Shell is one of things that you should generally try to avoid (ie. there by monsters, there)... unless there's "no other way." When there are builtin filters, like `version_compare`, there's obviously "a better way." – RVT Jul 14 '18 at 02:55

How to compare kernel (or other) version numbers in Ansible

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