Blog Post

Cara Install Kubernetes dengan Ansible di 2 Server (Master dan Worker)

June 25, 2025 Tutorial by Masdika.BIZ.ID

📅 Pendahuluan

Membangun cluster Kubernetes secara manual bisa memakan waktu dan rawan kesalahan. Dengan menggunakan Ansible, proses instalasi menjadi lebih otomatis, efisien, dan dapat direplikasi. Artikel ini membahas cara install Kubernetes dengan Ansible di 2 server, yaitu satu node master dan satu node worker.

🌐 Prasyarat

Sebelum memulai, pastikan:

💻 Memiliki 2 server dengan sistem operasi CentOS 8, Rocky Linux, AlmaLinux, atau RHEL.
🚀 Koneksi antar server berjalan dengan baik.
🔒 SSH root akses aktif, atau user dengan password yang dikonfigurasi pada file inventory.
🔎 Ansible sudah terinstal di server lain (sebagai control node).

Contoh Topologi:

🚜 Master: master-k8s (IP: 192.168.1.10)
🚜 Worker: worker-k8s (IP: 192.168.1.20)

🔧 Struktur Project Ansible

root@ansible:~/k8s-ansible# tree
.
├── inventory
│   └── hosts.ini
├── playbook.yml
├── reset-k8s.yml
└── roles
    ├── common
    │   └── tasks
    │       └── main.yml
    ├── containerd
    │   └── tasks
    │       └── main.yml
    ├── cri-tools
    │   └── tasks
    │       └── main.yml
    ├── kubernetes
    │   └── tasks
    │       └── main.yml
    ├── master-init
    │   └── tasks
    │       └── main.yml
    └── worker-join
        └── tasks
            └── main.yml

📜 Isi File Konfigurasi

Bagian ini berisi seluruh konfigurasi utama untuk deployment Kubernetes menggunakan Ansible. Mulai dari file inventory yang menentukan host master dan worker, playbook utama yang mengatur urutan eksekusi role, hingga reset playbook untuk membersihkan cluster. Setiap file memiliki fungsi spesifik dalam proses instalasi Kubernetes secara otomatis dan konsisten.

📂 inventory/hosts.ini

⚠️ Note: Jangan lupa ganti ansible_host, ansible_user, dan ansible_ssh_pass sesuai IP, username, dan password server yang kamu gunakan.

[master]
master-k8s ansible_host=192.168.1.10 ansible_user=root ansible_ssh_pass=passwd

[worker]
worker-k8s ansible_host=192.168.1.20 ansible_user=root ansible_ssh_pass=passwd

[all:vars]
ansible_python_interpreter=/usr/bin/python3

📄 playbook.yml

- name: Install dependencies and Kubernetes components
  hosts: all
  become: yes
  roles:
    - common
    - containerd
    - cri-tools
    - kubernetes

- name: Initialize Kubernetes master
  hosts: master
  become: yes
  roles:
    - master-init

- name: Join worker node to cluster
  hosts: worker
  become: yes
  roles:
    - worker-join

🔄 reset-k8s.yml

Digunakan untuk reset cluster jika ingin install ulang.

- name: Reset Kubernetes Cluster
  hosts: all
  become: yes
  tasks:
    - name: Reset kubeadm
      command: kubeadm reset -f

    - name: Remove Kubernetes config
      file:
        path: "{{ item }}"
        state: absent
      loop:
        - /etc/cni/net.d
        - /root/.kube
        - /etc/kubernetes
        - /var/lib/etcd
        - /var/lib/kubelet
        - /var/lib/cni
        - /run/containerd

    - name: Reload containerd and kubelet
      systemd:
        name: "{{ item }}"
        state: restarted
        enabled: yes
      loop:
        - containerd
        - kubelet

    - name: Clear iptables rules
      shell: |
        iptables -F
        iptables -t nat -F
        iptables -t mangle -F
        iptables -X

    - name: Clear IPVS rules
      shell: ipvsadm --clear
      ignore_errors: yes

    - name: Clean network interfaces
      shell: |
        ip link delete cni0 || true
        ip link delete flannel.1 || true
        ip link delete kube-bridge || true
      ignore_errors: yes

📄 Isi File `roles/common/tasks/main.yml`

- name: Install required system packages
  package:
    name:
      - tar
      - wget
      - curl
      - iproute
      - iproute-tc
      - iptables
    state: present

- name: Set hostname
  hostname:
    name: "{{ inventory_hostname }}"

- name: Update /etc/hosts
  lineinfile:
    path: /etc/hosts
    line: "{{ item }}"
    state: present
  loop:
    - "192.168.1.10 master-k8s"
    - "192.168.1.20 worker-k8s"

- name: Overwrite resolv.conf with reliable nameservers
  copy:
    dest: /etc/resolv.conf
    content: |
      nameserver 8.8.8.8
      nameserver 8.8.4.4
    owner: root
    group: root
    mode: '0644'

- name: Enable kernel modules
  copy:
    dest: /etc/modules-load.d/k8s.conf
    content: |
      overlay
      br_netfilter

- name: Load kernel modules
  modprobe:
    name: "{{ item }}"
  loop:
    - overlay
    - br_netfilter

- name: Apply sysctl params
  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

- name: Reload sysctl
  command: sysctl --system

- name: Disable swap
  shell: |
    swapoff -a
    sed -i.bak -r 's/(.+ swap .+)/#\1/' /etc/fstab
    (crontab -l 2>/dev/null; echo "@reboot /sbin/swapoff -a") | crontab -

📄 Isi File `roles/containerd/tasks/main.yml`

- name: Install required packages for containerd
  package:
    name: yum-utils
    state: present

- name: Add Docker repository
  shell: yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
  args:
    creates: /etc/yum.repos.d/docker-ce.repo

- name: Install containerd
  package:
    name: containerd.io
    state: present

- name: Create containerd config directory
  file:
    path: /etc/containerd
    state: directory
    mode: '0755'

- name: Generate default containerd config
  command: containerd config default
  register: containerd_config

- name: Write containerd config file
  copy:
    dest: /etc/containerd/config.toml
    content: "{{ containerd_config.stdout }}"
    owner: root
    group: root
    mode: '0644'

- name: Set SystemdCgroup to true
  replace:
    path: /etc/containerd/config.toml
    regexp: 'SystemdCgroup = false'
    replace: 'SystemdCgroup = true'

- name: Restart and enable containerd
  systemd:
    name: containerd
    enabled: true
    state: restarted

📄 Isi File `roles/cri-tools/tasks/main.yml`

- name: Download crictl
  get_url:
    url: https://github.com/kubernetes-sigs/cri-tools/releases/download/v1.33.0/crictl-v1.33.0-linux-amd64.tar.gz
    dest: /tmp/crictl.tar.gz

- name: Extract crictl
  unarchive:
    src: /tmp/crictl.tar.gz
    dest: /usr/local/bin
    remote_src: yes

- name: Remove crictl archive
  file:
    path: /tmp/crictl.tar.gz
    state: absent

- name: Create crictl config
  copy:
    dest: /etc/crictl.yaml
    content: |
      runtime-endpoint: unix:///run/containerd/containerd.sock
      image-endpoint: unix:///run/containerd/containerd.sock
      timeout: 2
      debug: true

📄 Isi File `roles/kubernetes/tasks/main.yml`

- name: Disable SELinux temporarily
  command: setenforce 0
  ignore_errors: yes

- name: Disable SELinux permanently
  replace:
    path: /etc/selinux/config
    regexp: '^SELINUX=enforcing'
    replace: 'SELINUX=permissive'

- name: Add Kubernetes repo
  copy:
    dest: /etc/yum.repos.d/kubernetes.repo
    content: |
      [kubernetes]
      name=Kubernetes
      baseurl=https://pkgs.k8s.io/core:/stable:/v1.33/rpm/
      enabled=1
      gpgcheck=1
      gpgkey=https://pkgs.k8s.io/core:/stable:/v1.33/rpm/repodata/repomd.xml.key

- name: Install Kubernetes components
  yum:
    name:
      - kubelet
      - kubeadm
      - kubectl
    state: present
    disable_excludes: kubernetes

- name: Enable and start kubelet
  systemd:
    name: kubelet
    enabled: yes
    state: started

📄 Isi File `roles/master-init/tasks/main.yml`

- name: Pull kubeadm images
  command: kubeadm config images pull --cri-socket unix:///var/run/containerd/containerd.sock

- name: Initialize the Kubernetes Master
  command: kubeadm init --pod-network-cidr=10.244.0.0/16 --cri-socket unix:///var/run/containerd/containerd.sock
  register: kubeadm_init_output
  args:
    creates: /etc/kubernetes/admin.conf

- name: Set up kube config directory
  file:
    path: /root/.kube
    state: directory
    mode: '0700'

- name: Copy admin.conf to kube config
  copy:
    src: /etc/kubernetes/admin.conf
    dest: /root/.kube/config
    remote_src: yes
    owner: root
    group: root
    mode: '0600'

- name: Deploy Calico network plugin
  shell: kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml
  environment:
    KUBECONFIG: /etc/kubernetes/admin.conf

- name: Generate kubeadm join command
  shell: kubeadm token create --print-join-command
  register: join_command

- name: Set join command fact
  set_fact:
    kube_join_command: "{{ join_command.stdout }} --cri-socket unix:///var/run/containerd/containerd.sock"

📄 Isi File `roles/worker-join/tasks/main.yml`

- name: Run join command on worker
  command: "{{ hostvars['master-k8s']['kube_join_command'] }}"

🏃 Langkah Menjalankan Playbook

ansible-playbook -i inventory/hosts.ini playbook.yml

Hasil akhir setelah proses selesai akan menampilkan status semua task yang telah dijalankan.

🔄 Untuk Reset Cluster:

ansible-playbook -i inventory/hosts.ini reset-k8s.yml

🎯 Verifikasi Cluster Kubernetes

kubectl get nodes --kubeconfig=/etc/kubernetes/admin.conf

🏙️ Kesimpulan

Dengan pendekatan ini, kamu bisa dengan mudah membuat cluster Kubernetes hanya dengan satu perintah. Ansible membantu mengurangi kesalahan manual dan mempercepat proses deployment. 💡