How to change the content of a YAML file (.kubeconfig)? - ansible

Question

I am learning Ansible & dealing with Kubernetes clusters. I would like to have an Ansible task which can change the value in .kube/config in my local Ansible host. For example, the .kube/config content looks like this:
apiVersion: v1
clusters:
- cluster:
server: xxx
name: xxx
contexts:
- context:
cluster: yyy
user: yyy
name: yyy
users:
- name: xxx
user: xxx
I basically would like to have an Ansible task to be able to do the following things:
change those values of xxx, yyy in the file .kube/config on ansible host.
append new content under each section of clusters, context & users if the values do not exist.
Is there a Kubernetes module or plugin I could directly use to achieve it? If not, could someone guide me how to achieve it?
==== I tried this ====
I tried :
- name: Update value to foo
replace:
path: ~/.kube/config
regexp: 'yyy'
regexp: 'foo'
delegate_to: localhost
When running the task, the file content doesn't change at all. Why? (Task has been executed based on logs)

Answer 1

Is there a kubernetes module or plugin I could directly use to achieve it?
Since your input file looks like valid YAML at a first glance, you could simply read it in via include_vars module – Load variables from files, dynamically within a task.
A minimal example playbook
---
- hosts: localhost
become: false
gather_facts: false
tasks:
- name: Read kubeconfig
include_vars:
file: kubeconfig
name: kubeconfig
- debug:
msg: "{{ kubeconfig }}"
- name: Write kubeconfig
copy:
content: "{{ kubeconfig | to_nice_yaml }}"
dest: kubeconf # for testing with new file name
resulting into an output of
TASK [debug] ********
ok: [localhost] =>
msg:
apiVersion: v1
clusters:
- cluster:
server: xxx
name: xxx
contexts:
- context:
cluster: yyy
user: yyy
name: yyy
users:
- name: xxx
user: xxx
~/test$ cat kubeconf
apiVersion: v1
clusters:
- cluster:
server: xxx
name: xxx
contexts:
- context:
cluster: yyy
user: yyy
name: yyy
users:
- name: xxx
user: xxx
Then do your data manipulation steps like changing values or append new content. After that write the data structure back into a new file or overwrite the existing one.
By following this approach one can keep the use case simple and by using out-of-box functionality.
Further Q&A
Ansible write variables into YAML file
Ansible: Add dictionary item into a YAML file
Write variable to a file in Ansible
Further Documentation
Since it is not possible to change or update existing variables, but register new ones with the same name, you may also have a look into
update_fact module – Update currently set facts