The purpose of this little (one metric right now!) Prometheus exporter is to expose the age of the AWS EC2 cloud image (AMI) that was used to launch an EC2 instance.
This then allows alerting on things like tell me if I have any instances launched with old images, which is useful when your patching strategy involves regularly building new cloud images and continually performing a rolling replacement of the compute fleet. An instance launched with a too-old cloud image probably means either a build failure somewhere, or the configuration hasn't been updated to use the latest image.
Pretty uncomplicated. Just run it. You don't even need to tell it an AWS
region, because it can autodiscover that from instance metadata. It listens on
tcp/9981 by default. To operate, it needs two things:
- access to the EC2 metadata API endpoint (http://169.254.169.254/...)
- access to the EC2 API endpoint for the region it is running in (https://...)
- AWS API credentials that will allow the
ec2:DescribeImagesAPI call. Provide these credentials via an IAM instance profile or equivalent.
Docker image can be found at
gcr.io/jsleeio-containers/ec2-metadata-exporter:v1.0.0