add: ansible k8s_node role

ansible/kubernetes/collections/requirements.yml

@@ -1,3 +1,4 @@
 ---
 collections:
-  - name: cloud.terraform
+  - name: cloud.terraform
+  - name: community.general

ansible/kubernetes/k8s_node.yml

@@ -0,0 +1,6 @@
+---
+- name: Prepare Kubernetes nodes
+  hosts: all
+
+  roles:
+    - role: k8s_node

ansible/kubernetes/roles/k8s_node/defaults/main.yml

@@ -0,0 +1,28 @@
+---
+k8s_version: "1.37"
+
+k8s_repo: "https://pkgs.k8s.io/core:/stable:/v{{ k8s_version }}/deb"
+k8s_repo_key: "https://pkgs.k8s.io/core:/stable:/v{{ k8s_version }}/deb/Release.key"
+
+k8s_packages:
+  - kubelet
+  - kubeadm
+
+k8s_prerequisite_packages:
+  - apt-transport-https
+  - ca-certificates
+  - curl
+  - gnupg
+
+k8s_firewall_admin_subnet: "192.168.66.0/24"
+k8s_firewall_ssh_port: "22"
+k8s_firewall_common_ports:
+  - "6443"
+  - "10250"
+k8s_firewall_master_ports:
+  - "2379:2380"
+  - "10257"
+  - "10259"
+k8s_firewall_worker_ports:
+  - "10256"
+  - "30000:32767"

ansible/kubernetes/roles/k8s_node/tasks/containerd.yml

@@ -0,0 +1,34 @@
+---
+- name: Install containerd
+  ansible.builtin.apt:
+    name: containerd
+    state: present
+    update_cache: true
+  become: yes
+
+- name: Create containerd configuration directory
+  ansible.builtin.file:
+    path: /etc/containerd
+    state: directory
+    mode: "0755"
+  become: yes
+
+- name: Generate default containerd configuration
+  ansible.builtin.shell:
+    cmd: containerd config default > /etc/containerd/config.toml
+    creates: /etc/containerd/config.toml
+  become: yes
+
+- name: Enable systemd cgroup driver in containerd
+  ansible.builtin.replace:
+    path: /etc/containerd/config.toml
+    regexp: '^(\s*)SystemdCgroup(\s*=\s*)false'
+    replace: '\1SystemdCgroup\2true'
+  become: yes
+
+- name: Enable and start containerd
+  ansible.builtin.systemd:
+    name: containerd
+    state: restarted
+    enabled: true
+  become: yes

ansible/kubernetes/roles/k8s_node/tasks/firewall.yml

@@ -0,0 +1,44 @@
+---
+- name: Allow SSH from admin subnet
+  community.general.ufw:
+    rule: allow
+    port: "{{ k8s_firewall_ssh_port }}"
+    proto: tcp
+    from_ip: "{{ k8s_firewall_admin_subnet }}"
+  become: yes
+
+- name: Allow common Kubernetes ports from admin subnet
+  community.general.ufw:
+    rule: allow
+    port: "{{ item }}"
+    proto: tcp
+    from_ip: "{{ k8s_firewall_admin_subnet }}"
+  become: yes
+  loop: "{{ k8s_firewall_common_ports }}"
+
+- name: Allow etcd and control plane ports on control-plane nodes
+  community.general.ufw:
+    rule: allow
+    port: "{{ item }}"
+    proto: tcp
+    from_ip: "{{ k8s_firewall_admin_subnet }}"
+  become: yes
+  loop: "{{ k8s_firewall_master_ports }}"
+  when: inventory_hostname in groups['master']
+
+- name: Allow kube-proxy and NodePort ports on worker nodes
+  community.general.ufw:
+    rule: allow
+    port: "{{ item }}"
+    proto: tcp
+    from_ip: "{{ k8s_firewall_admin_subnet }}"
+  become: yes
+  loop: "{{ k8s_firewall_worker_ports }}"
+  when: inventory_hostname in groups['worker']
+
+- name: Enable ufw and deny incoming by default
+  community.general.ufw:
+    state: enabled
+    policy: deny
+    direction: incoming
+  become: yes

ansible/kubernetes/roles/k8s_node/tasks/main.yml

@@ -0,0 +1,5 @@
+---
+- ansible.builtin.import_tasks: system.yml
+- ansible.builtin.import_tasks: packages.yml
+- ansible.builtin.import_tasks: containerd.yml
+- ansible.builtin.import_tasks: firewall.yml

ansible/kubernetes/roles/k8s_node/tasks/packages.yml

@@ -0,0 +1,36 @@
+---
+- name: Install prerequisite packages
+  ansible.builtin.apt:
+    name: "{{ k8s_prerequisite_packages }}"
+    state: present
+    update_cache: true
+  become: yes
+
+- name: Add Kubernetes apt key
+  ansible.builtin.apt_key:
+    url: "{{ k8s_repo_key }}"
+    keyring: /etc/apt/keyrings/kubernetes-apt-keyring.gpg
+    state: present
+  become: yes
+
+- name: Add Kubernetes apt repository
+  ansible.builtin.apt_repository:
+    repo: "deb [signed-by=/etc/apt/keyrings/kubernetes-apt-keyring.gpg] {{ k8s_repo }} /"
+    state: present
+    filename: kubernetes
+  become: yes
+
+- name: Install kubelet and kubeadm
+  ansible.builtin.apt:
+    name: "{{ k8s_packages }}"
+    state: present
+    update_cache: true
+  become: yes
+
+- name: Hold kubelet and kubeadm packages
+  ansible.builtin.command:
+    cmd: apt-mark hold {{ item }}
+  loop: "{{ k8s_packages }}"
+  register: _kube_hold
+  become: yes
+  changed_when: "'already set on hold' not in _kube_hold.stdout"

ansible/kubernetes/roles/k8s_node/tasks/system.yml

@@ -0,0 +1,51 @@
+---
+- name: Disable swap
+  ansible.builtin.shell:
+    cmd: swapoff -a
+  become: yes
+  changed_when: false
+
+- name: Comment out swap entries in fstab
+  ansible.builtin.replace:
+    path: /etc/fstab
+    regexp: '^(\s*[^#\s][^\s]*\s+swap\s+.*)$'
+    replace: '# \1'
+  become: yes
+
+- name: Load overlay kernel module
+  ansible.builtin.shell:
+    cmd: modprobe overlay
+  become: yes
+  changed_when: false
+  failed_when: false
+
+- name: Load br_netfilter kernel module
+  ansible.builtin.shell:
+    cmd: modprobe br_netfilter
+  become: yes
+  changed_when: false
+
+- name: Persist kernel modules
+  ansible.builtin.copy:
+    dest: /etc/modules-load.d/k8s.conf
+    content: |
+      overlay
+      br_netfilter
+    mode: "0644"
+  become: yes
+
+- name: Configure kernel network settings
+  ansible.builtin.copy:
+    dest: /etc/sysctl.d/k8s.conf
+    content: |
+      net.bridge.bridge-nf-call-iptables  = 1
+      net.bridge.bridge-nf-call-ip6tables = 1
+      net.ipv4.ip_forward                 = 1
+    mode: "0644"
+  become: yes
+
+- name: Apply kernel network settings
+  ansible.builtin.command:
+    cmd: sysctl --system
+  become: yes
+  changed_when: false