🔐 Programmatically Discovering RHEL Ansible Node IPs in AWS (Boto3)
support@whitefeathers.org
In automated RHEL + Ansible environments on AWS, hardcoding host IPs doesn’t scale.
This small utility queries EC2 and prints private IP addresses for instances matching a naming
convention (ansible-rhel*) inside a specific VPC.
🧠 What this script does
- Connects to EC2 in
us-east-1 - Filters by VPC ID and Name tag pattern
ansible-rhel* - Limits results to instances in the
runningstate - Returns/prints one private IP per line (ideal for inventory pipelines)
⚙️ Filters used
- Region:
us-east-1 - VPC:
vpc-0fc278c7fb8ffdbee(note: your comment referencesvpc-03ac09e77d044aabc) - Name tag:
ansible-rhel* - State:
running
Tip: If you meant the VPC in the header comment, update the filter to match it.
🧩 Source Code
# This function retrieves all internal IP addresses of RHEL Ansible nodes
# located in the 'us-east-1' region within the VPC 'vpc-03ac09e77d044aabc'.
# It returns a list of IP addresses, each on a new line, for instances
# whose names start with 'ansible-rhel*'.
# support@whitefeathers.org
import boto3 # Corrected import statement
def get_rhel_ansible_node_ips():
"""
Retrieve the private IP addresses of running RHEL instances in a specified VPC.
This function uses the Boto3 library to interact with the AWS EC2 service. It filters instances
based on the provided VPC ID and a tag that matches 'ansible-rhel*'. The function returns a list
of private IP addresses for all instances that are currently in the 'running' state.
Returns:
list: A list of private IP addresses of the matching EC2 instances.
"""
ec2 = boto3.client('ec2', region_name='us-east-1')
response = ec2.describe_instances(
Filters=[
{'Name': 'vpc-id', 'Values': ['vpc-0fc278c7fb8ffdbee']},
{'Name': 'tag:Name', 'Values': ['ansible-rhel*']},
{'Name': 'instance-state-name', 'Values': ['running']}
]
)
ip_addresses = []
for reservation in response['Reservations']:
for instance in reservation['Instances']:
ip_addresses.append(instance['PrivateIpAddress'])
return ip_addresses
def main():
ip_addresses = get_rhel_ansible_node_ips()
for ip in ip_addresses:
print(ip)
if __name__ == "__main__":
main()
📤 Example Output
10.20.4.17
10.20.4.23
10.20.5.11
🔄 Common extensions
- Emit JSON for a dynamic Ansible inventory
- Add additional filters (AMI, AZ, instance type)
- Assume-role support for cross-account discovery
- Pipe into post-patch validation workflows
© WhiteFeathers.org — automation patterns for AWS, RHEL, and Ansible.
