Mastering Automation: Installing Ansible on Amazon Linux

Automation underpins scalable infrastructure. For those standardizing on AWS, Amazon Linux provides an optimized platform, yet installing Ansible isn’t a straight copy from generic CentOS or Ubuntu instructions. Amazon Linux’s package management ecosystem and repository setup introduce specific steps—miss one, and dependency conflicts or outdated versions follow.

Context: Why Install Ansible on Amazon Linux?

AWS-native Linux hosts benefit from tightly maintained kernel versions and improved lifecycle security, and integrating with Ansible unlocks:

• Consistent IaC across ephemeral EC2 fleets
• Low friction for patch workflows and ephemeral environment setups
• Smooth use of SSM or cloud-init layering

Many organizations underestimate operational pitfalls when Ansible is installed ad hoc, especially on older EC2 AMIs.

Prerequisites

• EC2 Host: Amazon Linux 2 (2023 or newer) or legacy Amazon Linux AMI.
• Privileges: ec2-user with sudo.
• Network: Outbound internet connectivity to AWS repos and EPEL.

SSH in:

ssh -i ~/.ssh/aws.pem ec2-user@ec2-XX-XX-XX-XX.compute-1.amazonaws.com

Update the host OS immediately—skipping this risks mismatched dependencies:

sudo yum -y update

If a kernel update is included, a reboot is required before proceeding with heavy automation.

Amazon Linux 2: Installation

Key difference: Amazon Linux 2 does not ship with Ansible in its default repositories. Even yum search ansible will return no results until the correct channel is enabled.

Enable the EPEL-compatible repository via amazon-linux-extras:

sudo amazon-linux-extras enable epel
# Confirm epel status
amazon-linux-extras | grep epel

Once enabled, install:

sudo yum install -y ansible

Known issue: On some instances, amazon-linux-extras is present but fails if the OS is pre-2022. Check /etc/system-release for build date; consider replacement if OS is EOL.

Optional: For newer Ansible (v2.10+), consider pip-based installs—but that adds Python pip management complexity and isn’t best practice for long-lived hosts.

Verify install and path:

ansible --version
which ansible

Look for output like:

ansible [core 2.9.27]
  config file = /etc/ansible/ansible.cfg
  python version = 2.7.18 (default, Aug 17 2023, 23:00:38) [GCC 7.3.1 2020 Red Hat 7.3.1-16]

Note: Amazon Linux 2 commonly runs Python 2.7; several modern Ansible modules require Python 3. If you plan to use modules with Python 3 requirement, install Python 3 and re-link /usr/bin/python.

Amazon Linux 1 (Legacy): Installation

For pre-2018 AMIs, neither amazon-linux-extras nor consistent Ansible binaries are available from the main repos. Legacy approach:

1. Add EPEL manually:

sudo yum install -y https://dl.fedoraproject.org/pub/epel/epel-release-latest-6.noarch.rpm

2. Ensure Python and pip:
Some instances are missing even Python or pip.

sudo yum install -y python python-pip
sudo pip install --upgrade pip

3. Install Ansible using pip:
Repository Ansible is commonly too outdated; pip delivers a newer core.

sudo pip install 'ansible<2.10' --upgrade

Critical: Pin to <2.10 for compatibility with older Python unless you have upgraded system Python.

4. Validate install:

ansible --version

If you get:

-bash: ansible: command not found

Then ensure /usr/local/bin is in your $PATH. This is a recurrent gotcha on classic Amazon Linux AMIs.

Quick Validation

Create a minimal test inventory:

# hosts.ini
[local]
localhost ansible_connection=local

[aws-ec2]
ec2-XX-XX-XX-XX.compute-1.amazonaws.com ansible_user=ec2-user ansible_ssh_private_key_file=~/.ssh/aws.pem

Test connectivity:

ansible all -i hosts.ini -m ping

Expected output signals correct SSH key permissions and successful module execution:

localhost | SUCCESS => {
    "changed": false,
    "ping": "pong"
}
ec2-... | SUCCESS => {
    "changed": false,
    "ping": "pong"
}

Pro tip: If you hit the error

Permission denied (publickey).
fatal: [ec2-...]: UNREACHABLE! => {"changed": false, "msg": "Failed to connect"}

double-check SSH key file mode: chmod 400 ~/.ssh/aws.pem.

Troubleshooting & Notes

Note: Amazon Linux package life is coupled to AWS release cycles; if you require bleeding-edge Ansible versions or advanced plugins, develop a containerized control environment instead of system-level install—reduces semantic drift in multi-host workflows.

Conclusion

Correctly installing Ansible on Amazon Linux means respecting the specific repository layouts and Python versions shipped by AWS. Using amazon-linux-extras for Amazon Linux 2 or pip for legacy AMIs avoids the most common failure modes. For team-scale or CI/CD uses, standardize inventory and control node setup via code—manual installs drift over time.

For playbook development, avoid targeting multiple major Ansible versions unless justified by legacy host constraints. Reality: inventory or group_vars files sometimes require workarounds for old Python, especially on classic AMIs. If you run into inconsistent module support, default back to explicit interpreter definition in ansible.cfg.

A good install is boring: you won't think about it for months. That’s the goal.