Ansible is a powerful automation tool that makes it easy to manage and configure servers, applications, and infrastructure. As your infrastructure expands, your Ansible playbooks become more complex and time-consuming. Keeping Ansible running efficiently is crucial for maintaining a responsive and scalable environment. Here are some practical suggestions for optimizing Ansible for faster performance.

1. Optimize Inventory Management

Ansible’s inventory management is the starting point for optimizing playbook execution:

• Dynamic Inventory: Use dynamic inventory scripts to generate your inventory on the fly, especially in cloud environments. This reduces the overhead of maintaining static inventory files and ensures up-to-date host information. here a link how can you use terraform and ansible to generate Dynamic Inventory.
• Limit Scope: Use the --limit option to restrict playbook execution to specific hosts or groups. This avoids unnecessary tasks on unrelated hosts.

2. Reduce SSH Overhead

Ansible communicates with remote hosts primarily over SSH, so optimizing SSH can lead to significant performance gains:

• Control Persist: Enable SSH connection multiplexing to reuse SSH connections, reducing the time spent establishing connections. Add the following to your SSH configuration (~/.ssh/config):

Host *
  ControlMaster auto
  ControlPath /tmp/ssh-%r@%h:%p
  ControlPersist 10m

• Parallelism: Increase the number of parallel SSH connections using the -f or --forks option. The default is 5, but you can increase it based on your infrastructure capabilities:

ansible-playbook -f 10 playbook.yml

3. Efficient Playbook Design

Designing your playbooks efficiently can significantly reduce execution time:

• Task Optimization: Combine related tasks to minimize the number of remote executions. For example, instead of running multiple commands individually, use a shell script or a command with multiple arguments.
• Idempotence: Ensure tasks are idempotent, meaning they only make changes when necessary. This reduces redundant operations and speeds up re-runs. For example, run apt update only if the “Download nginx apt key” task is changed.

- name: Download nginx apt key
  get_url: 
    url: http://nginx.org/keys/nginx_signing.key 
    dest: /var/keys/nginx_signing.key
  register: aptkey

- name: Add nginx apt key
  command: "apt-key add /var/keys/nginx_signing.key"
  when: aptkey.changed

- name: Update apt cache
  apt: 
    update_cache: yes
  when: aptkey.changed

4. Use Asynchronous Tasks

Asynchronous tasks allow playbooks to continue executing without waiting for long-running tasks to complete:

• Async and Poll: Use the async and poll keywords to run tasks asynchronously. For example:

- name: Long-running task
  command: /path/to/long/task
  async: 3600
  poll: 0
  register: task_result

- name: Check async task result
  async_status:
    jid: "{{ task_result.ansible_job_id }}"
  register: job_result
  until: job_result.finished
  retries: 30
  delay: 10

5. Enable Fact Caching

Fact gathering can be time-consuming, especially for large inventories. Enable fact caching to store and reuse host facts:

• Cache Backend: Configure a cache backend (e.g., JSON, Redis) in your ansible.cfg

[defaults]
fact_caching = jsonfile
fact_caching_connection = /path/to/cache

6. Minimize the Use of wait_for and pause

Excessive use of wait_for and pause can slow down playbook execution:

• Conditional Checks: Replace static pauses with conditional checks. For instance, wait for a port to open instead of pausing for a fixed duration:

- name: Wait for service to start
  wait_for:
    port: 8080
    state: started

7. Profile Playbook Performance

Profiling helps identify bottlenecks in your playbooks:

• Callback Plugins: Use callback plugins like profile_tasks to measure the time taken by each task. Enable it in your ansible.cfg:

[defaults]
callback_whitelist = profile_tasks

8. Use Mitogen for Ansible

Mitogen is a third-party plugin for Ansible that can drastically improve execution speed by optimizing the communication layer between Ansible and remote hosts:

• First, install Mitogen via pip:

pip install mitogen ansible

Configure Mitogen: Modify your ansible.cfg to use Mitogen as the strategy plugin:

[defaults]
strategy_plugins = /path/to/mitogen-ansible/ansible_mitogen/plugins/strategy
strategy = mitogen_linear

Mitogen can significantly reduce the overhead associated with Ansible’s SSH-based communication by using persistent connections and improving task execution efficiency.

Remember, the key to Ansible performance optimization lies in continuous monitoring and iterative improvement. Regularly profile your playbooks, analyze the results, and refine your configurations to achieve the best performance for your infrastructure.