refactor(k3s): enhance kubeconfig generation and token management

Signed-off-by: Tuan-Dat Tran <tuan-dat.tran@tudattr.dev>

roles/k3s_server/tasks/create_kubeconfig.yml

@@ -0,0 +1,87 @@
+---
+- name: Slurp original k3s.yaml from primary K3s server
+  ansible.builtin.slurp:
+    src: /etc/rancher/k3s/k3s.yaml
+  register: original_k3s_kubeconfig_slurp
+  become: true
+
+- name: Parse original k3s.yaml content to extract cert data
+  ansible.builtin.set_fact:
+    original_parsed_k3s_kubeconfig: "{{ original_k3s_kubeconfig_slurp.content | b64decode | from_yaml }}"
+  delegate_to: localhost
+  run_once: true
+
+- name: Set facts for certificate and key data needed by the template
+  ansible.builtin.set_fact:
+    k3s_server_ca_data: "{{ original_parsed_k3s_kubeconfig.clusters[0].cluster['certificate-authority-data'] }}"
+    k3s_client_cert_data: "{{ original_parsed_k3s_kubeconfig.users[0].user['client-certificate-data'] }}"
+    k3s_client_key_data: "{{ original_parsed_k3s_kubeconfig.users[0].user['client-key-data'] }}"
+  delegate_to: localhost
+  run_once: true
+
+- name: Decode and save K3s Server CA certificate
+  ansible.builtin.copy:
+    content: "{{ k3s_server_ca_data | b64decode }}"
+    dest: "/tmp/k3s-ca.crt"
+    mode: "0644"
+  delegate_to: localhost
+  become: false
+
+- name: Decode and save K3s Client certificate
+  ansible.builtin.copy:
+    content: "{{ k3s_client_cert_data | b64decode }}"
+    dest: "/tmp/k3s-client.crt"
+    mode: "0644"
+  delegate_to: localhost
+  become: false
+
+- name: Decode and save K3s Client key
+  ansible.builtin.copy:
+    content: "{{ k3s_client_key_data | b64decode }}"
+    dest: "/tmp/k3s-client.key"
+    mode: "0600"
+  delegate_to: localhost
+  become: false
+
+- name: Add K3s cluster to kubeconfig
+  ansible.builtin.command: >
+    kubectl config set-cluster "{{ k3s_cluster_name }}"
+    --server="https://{{ k3s_server_name }}:6443"
+    --certificate-authority=/tmp/k3s-ca.crt
+    --embed-certs=true
+  environment:
+    KUBECONFIG: "{{ ansible_env.HOME }}/.kube/config"
+  delegate_to: localhost
+  become: false
+
+- name: Add K3s user credentials to kubeconfig
+  ansible.builtin.command: >
+    kubectl config set-credentials "{{ k3s_user_name }}"
+    --client-certificate=/tmp/k3s-client.crt
+    --client-key=/tmp/k3s-client.key
+    --embed-certs=true
+  environment:
+    KUBECONFIG: "{{ ansible_env.HOME }}/.kube/config"
+  delegate_to: localhost
+  become: false
+
+- name: Add K3s context to kubeconfig
+  ansible.builtin.command: >
+    kubectl config set-context "{{ k3s_context_name }}"
+    --cluster="{{ k3s_cluster_name }}"
+    --user="{{ k3s_user_name }}"
+  environment:
+    KUBECONFIG: "{{ ansible_env.HOME }}/.kube/config"
+  delegate_to: localhost
+  become: false
+
+- name: Clean up temporary certificate and key files
+  ansible.builtin.file:
+    path: "{{ item }}"
+    state: absent
+  loop:
+    - "/tmp/k3s-ca.crt"
+    - "/tmp/k3s-client.crt"
+    - "/tmp/k3s-client.key"
+  delegate_to: localhost
+  become: false