Ansible + Cisco idempotence - ansible

Question

So I'm doing some testing with Ansible to manage Cisco devices (specifically a 3750 in this case).
I'm able to add my VLAN's and Loopbacks with no issue.
Just trying to get Ansible to stop registering a change in the task when the Loopback or VLAN exists.
Right now my play looks like this:
- name: Set the IP for Loop 0
ios_config:
provider: "{{ connection }}"
lines:
- description AnsibleLoop0
- ip address 8.8.8.8 255.255.255.0
before:
- interface Loopback0
match: exact
Anytime this task is run, Ansible registers it like a change:
changed: [switch] => {"changed": true, "updates": ["interface Loopback0", "description AnsibleLoop0", "ip address 8.8.8.8 255.255.255.0"], "warnings": []}
I've tried different match types (line, exact) to no avail.
Maybe I'm getting something wrong here.
I thought that if I had the play insert the lines exactly like how they would show up in a show run it wouldnt register it as a change?
Any help here would be appreciated!

Answer 1

You could be experiencing this issue:
https://github.com/ansible/ansible/pull/24345
Are you saving the configuration changes each time to the Cisco device using save: "yes” in your playbook? I had the same problem and I was saving the config each time the playbook ran. Setting that to no just to test, after the first run reports changed=True sequential runs would report back changed=False by Ansible.

Answer 2

I know this thread has been closed a long ago but just had the same problem and found what was causing it for me.
I am configuring L3 interfaces using a json file as a source, on which I did not realize I was using the value for interface name on uppercase like this: Loopback123
This is the result when using that:
changed: [NX-SPINE-2] => (item={'interface': 'Loopback123', 'ip': '123.1.2.8/32', 'description': 'Loopback interface for Ansible Testing'})
changed: [NX-SPINE-1] => (item={'interface': 'Loopback123', 'ip': '123.1.2.7/32', 'description': 'Loopback interface for Ansible Testing'})
changed: [NX-LEAF-3] => (item={'interface': 'Loopback123', 'ip': '123.1.2.5/32', 'description': 'Loopback interface for Ansible Testing'})
changed: [NX-LEAF-2] => (item={'interface': 'Loopback123', 'ip': '123.1.2.4/32', 'description': 'Loopback interface for Ansible Testing'})
changed: [NX-LEAF-4] => (item={'interface': 'Loopback123', 'ip': '123.1.2.6/32', 'description': 'Loopback interface for Ansible Testing'})
PLAY RECAP ****************************************************************************************************************************************************
NX-LEAF-1 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-2 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-3 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-4 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-SPINE-1 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-SPINE-2 : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
This is due to interface name actually being different to how the device treats and displays the name back when showing the configuration.
interface loopback0
description Management - BGP peering
Once I corrected the interface name to lower case on the source file, this solved the idempotency check for me.
ok: [NX-LEAF-4] => (item={'interface': 'loopback123', 'ip': '123.1.2.6/32', 'description': 'Loopback interface for Ansible Testing'})
ok: [NX-LEAF-3] => (item={'interface': 'loopback123', 'ip': '123.1.2.5/32', 'description': 'Loopback interface for Ansible Testing'})
PLAY RECAP ****************************************************************************************************************************************************
NX-LEAF-1 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-2 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-3 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-LEAF-4 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-SPINE-1 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
NX-SPINE-2 : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
Hope it helps.
Cheers!