Configuration Management in DevOps: The Role of Ansible | by Anuradha Iyer | Oct, 2024

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Ansible and containers work together in a way that bridges the gap between configuration management and container orchestration. Ansible automates the management, deployment, and configuration of containers, just as it does for traditional infrastructure, allowing you to manage containerized applications effectively.

Here’s a breakdown of how Ansible ties up with containers:

Ansible comes with dedicated modules to interact with Docker containers, allowing you to perform various tasks like building images, starting containers, and managing Docker networks. These modules include:

  • docker_container: Manages the lifecycle of a container (start, stop, restart, etc.).
  • docker_image: Allows you to build, pull, and manage Docker images.
  • docker_network: Manages Docker networks.
  • docker_volume: Manages Docker volumes.

Using these modules, you can automate the process of deploying and configuring containers.

Example:

You can define a task in an Ansible playbook to deploy a container running Nginx:

- name: Run Nginx container
docker_container:
name: nginx
image: nginx:latest
state: started
ports:
- "80:80"

This will automatically pull the latest Nginx image and run the container, ensuring it is accessible on port 80.

Ansible can help you treat your container infrastructure as code, just like traditional servers. Instead of manually building and managing container environments, you can use playbooks to define the setup, allowing for consistent and repeatable deployments. For example, you can:

  • Install Docker on hosts.
  • Create Docker networks, volumes, and containers.
  • Build and manage container images.

Ansible makes it easy to ensure that your container environments are configured the same way every time.

While Ansible is not a container orchestrator like Kubernetes, it can complement container orchestration platforms. You can use Ansible to configure Kubernetes clusters, manage Docker Swarm, or integrate with other orchestration tools like OpenShift. Ansible can automate the setup of orchestration platforms, allowing you to define the state of your clusters, services, and networks.

Example:

You can use Ansible to deploy and manage Kubernetes by automating tasks like installing kubeadm and managing pods or services.

- name: Install kubeadm
apt:
name: kubeadm
state: present

Containers typically run isolated environments, but sometimes they need additional configuration beyond just launching an image. For instance, you might want to configure application settings or manage files inside a container. Ansible can:

  • Copy files into a running container.
  • Execute commands inside a container to perform configuration tasks.
  • Ensure the desired state of the container’s environment.

This is useful for more advanced container setups where simple image configurations are not enough.

Example:

To run a command inside a running container:

- name: Run setup script inside a container
docker_container_exec:
container: my_container
command: /usr/local/bin/setup.sh

Ansible integrates well into CI/CD pipelines, allowing you to automate the entire lifecycle of containers — from building images, deploying them, and configuring them in production environments. You can combine Ansible with tools like Jenkins, GitLab CI, or other CI/CD systems to manage the deployment of containers in automated workflows.

When running multiple containers (e.g., a microservices architecture), you may need to ensure that all containers are orchestrated correctly and communicate with each other. Ansible can define tasks to manage inter-container dependencies, start specific containers in a specific order, and ensure that network and storage configurations are set up correctly.

For example, using Ansible’s docker_compose module, you can automate the deployment of multi-container applications defined in a docker-compose.yml file.

- name: Deploy multi-container app with Docker Compose
docker_compose:
project_src: /path/to/docker-compose.yml
state: present

In many organizations, containers coexist with traditional infrastructure. Ansible helps manage this hybrid environment, ensuring that both containerized and non-containerized services are configured, deployed, and maintained consistently. This is particularly useful for companies transitioning from traditional systems to a containerized architecture.

  • Unified Automation: Manage both containers and traditional infrastructure using the same playbooks and Ansible roles.
  • Consistency: Ansible ensures that your containerized services are configured and deployed consistently across multiple environments.
  • Orchestration Integration: Though Ansible is not an orchestrator itself, it can help manage container orchestration platforms like Kubernetes, Docker Swarm, and OpenShift.
  • CI/CD Automation: Automate container build, deployment, and configuration processes as part of a CI/CD pipeline.

Ansible makes it easier to work with containers by providing automation that scales from development to production, regardless of whether you are dealing with a single container or a complex multi-container architecture.