railiance-cluster/ansible/harden.yml

---
- name: Server hardening
  hosts: all
  become: true

  vars:
    ssh_port: 22
    k3s_api_port: 6443
    flannel_vxlan_port: 8472

  tasks:
    # ── SSH hardening ────────────────────────────────────────────────────────

    - name: Disable root SSH login
      lineinfile:
        path: /etc/ssh/sshd_config
        regexp: '^#?PermitRootLogin'
        line: 'PermitRootLogin no'
        state: present
      notify: Restart sshd

    - name: Disable password authentication
      lineinfile:
        path: /etc/ssh/sshd_config
        regexp: '^#?PasswordAuthentication'
        line: 'PasswordAuthentication no'
        state: present
      notify: Restart sshd

    - name: Disable challenge-response authentication
      lineinfile:
        path: /etc/ssh/sshd_config
        regexp: '^#?ChallengeResponseAuthentication'
        line: 'ChallengeResponseAuthentication no'
        state: present
      notify: Restart sshd

    # ── UFW firewall ─────────────────────────────────────────────────────────

    - name: Install ufw
      apt:
        name: ufw
        state: present
        update_cache: yes

    - name: Set UFW default inbound policy to deny
      ufw:
        default: deny
        direction: incoming

    - name: Set UFW default outbound policy to allow
      ufw:
        default: allow
        direction: outgoing

    - name: Allow SSH
      ufw:
        rule: allow
        port: "{{ ssh_port }}"
        proto: tcp

    - name: Allow k3s API server
      ufw:
        rule: allow
        port: "{{ k3s_api_port }}"
        proto: tcp

    - name: Allow Flannel VXLAN (inter-node)
      ufw:
        rule: allow
        port: "{{ flannel_vxlan_port }}"
        proto: udp

    - name: Enable UFW
      ufw:
        state: enabled

    # ── fail2ban ─────────────────────────────────────────────────────────────

    - name: Install fail2ban
      apt:
        name: fail2ban
        state: present

    - name: Configure fail2ban SSH jail
      copy:
        dest: /etc/fail2ban/jail.d/sshd.conf
        content: |
          [sshd]
          enabled  = true
          port     = {{ ssh_port }}
          maxretry = 5
          bantime  = 3600
          findtime = 600
        mode: '0644'
      notify: Restart fail2ban

    - name: Enable and start fail2ban
      systemd:
        name: fail2ban
        enabled: true
        state: started

    # ── Shell hygiene ─────────────────────────────────────────────────────────

    - name: Set HISTCONTROL to suppress space-prefixed commands from history
      copy:
        dest: /etc/profile.d/histcontrol.sh
        content: |
          # Commands prefixed with a space are not recorded in shell history.
          # Use this when typing secrets interactively.
          export HISTCONTROL=ignorespace
        mode: '0644'

  handlers:
    - name: Restart sshd
      systemd:
        name: sshd
        state: restarted

    - name: Restart fail2ban
      systemd:
        name: fail2ban
        state: restarted