Linux equivalent of WSUS with Ansible and Squid

2 minute read

As soon as I saw Linux happily growing up over the landscape, I realized manually patching would not be the best option, so I had to make up something to drive this on a monthly basis.

To make things more interesting, almost all Linux I had were not internet connected, so I ended up tweaking one Linux to serve as a internet proxy (I told you how I did here) and then, used Ansible to spread all patches down.

Let’s do it!

Few words about Ansible

Ansible is purely Infrastructure as Code (IaC), software provisioning, “open source community project sponsored by Red Hat”, as they stated on their home page https://www.ansible.com

Architecture

  • Controller > Computer which orchestrates the solution
  • Nodes > Every computer handled by controller via SSH

Pre-Requisites per node

Preparing the Controller

1.Installing Ansible

First, added ansible repository and installed as usual

sudo apt-add-repository ppa:ansible/ansible
sudo apt update
sudo apt install ansible
sudo apt install sshpass -y

2.Inventory File

After that, made Inventory file; containing information about hosts to be updated.
They can be grouped. Also, variables can be used to force settings on certain playbooks and templates.

Created this way, with the following content

sudo nano /etc/ansible/hosts
[linux]
test1 ansible_host=computer1.domain.com
test2 ansible_host=computer2.domain.com

[all:vars]
ansible_user='ansible'
ansible_become=yes
ansible_become_method=sudo
ansible_python_interpreter='/usr/bin/python3'

Checked inventory file this way:

ansible-inventory --list -y

Testing Inventory file

3.SSH Key

Generated an SSH key on the Controller

ssh-keygen

[Enter]  [Enter]  [Enter]

Generated SSH key

Preparing Nodes (Clients)

Enabled SSH User with root permission without password from Controller

1.Added ansible user on every destination host or Node

sudo adduser ansible

Adding ansible User

2.Configured password-less sudo access on every Node

echo "ansible ALL=(ALL) NOPASSWD:ALL" | sudo tee /etc/sudoers.d/ansible

Configured password-less

3.From the Controller, copied SSH public key to every Node

ssh-copy-id ansible@[COMPUTER_NAME]

Copied SSH public key

4.On every Node, disabled password-based login for the ansible user

sudo usermod -L ansible

Disabled password-based loging for user

5.From the Controller, checked everything was properly set

ansible all -m ping -u ansible

Testing hosts file

Listing Pending Updates

Prepared file /etc/ansible/list-updates.yml with the following content

---
- name: Updates Linux Ubuntu 20.4 Servers
  hosts: linux
  become: true
  become_user: root
  vars:
    proxy_env:
      http_proxy: http://[COMPUTER_NAME_PROXY]:8080
  tasks:
  # collect information
  - name: apt-get listonly collect
    shell: apt-get --just-print upgrade 2>&1 | perl -ne 'if (/Inst\s([\w,\-,\d,\.,~,:,\+]+)\s\[([\w,\-,\d,\.,~,:,\+]+)\]\s\(([\w,\-,\d,\.,~,:,\+]+)\)? /i) {print "PROGRAM= $1 INSTALLED= $2 AVAILABLE= $3\n"}' | column -s ' ' -t
    args:
      warn: false
    register: apt_listonly
    changed_when: false
    environment: ""

  # apt-get listonly output
  - name: needrestart -lb output
    debug: var=apt_listonly.stdout_lines
    changed_when: false
    environment: ""

List Updates file

Listed pending updates:

ansible-playbook -i hosts list-updates.yml -v

Pending updates list

Applying Pending Updates

Prepared file /etc/ansible/apply-updates.yml with the following content

---
- hosts: linux  become: true
  become_user: root
  vars:
    proxy_env:
      http_proxy: http://[COMPUTER_NAME_PROXY]:8080
  tasks:
    - name: Update apt repo and cache on all Debian/Ubuntu boxes
      apt: update_cache=yes force_apt_get=yes cache_valid_time=3600
      environment: ""

    - name: Upgrade all packages on servers
      apt: upgrade=dist force_apt_get=yes
      environment: ""

    - name: Check if a reboot is needed on all servers
      register: reboot_required_file
      stat: path=/var/run/reboot-required get_md5=no

    - name: Reboot the box if kernel updated
      reboot:
        msg: "Reboot initiated by Ansible for kernel updates"
        connect_timeout: 5
        reboot_timeout: 300
        pre_reboot_delay: 0
        post_reboot_delay: 30
        test_command: uptime
      when: reboot_required_file.stat.exists

Applied pending updates:

ansible-playbook -i hosts apply-updates.yml -v

Applied updates

In this case, both nodes were updated without errors (when they appears, normally are in red)

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