belminf/etcd-aws-asg-cluster repository overview

⁠etcd-aws-asg-cluster

Docker image for AWS ASG instances that has some logic to build a cluster by using aws-cli to retrieve a list of ASG members.

NOTE: Not even close to production ready. Not using TLS verification between members, for instance. Also, haven't tested failure states.

⁠Logic

1. Use aws-cli to retrieve ASG membership.
2. Loop A: Do $RETRIES times:
   1. Random sleep to spread out instances standing up at the same time.
   2. Loop B: For every member of the ASG
      1. Try to join etcd cluster at ASG member:
         • Connected: Break Loop B and Loop A
         • Not connected: Continue Loop B
   3. If we never connected, and we're first on the ASG member list (sorted alphabetical by instance ID), we make a cluster of 1 node
      • The first in the ASG member list is a requirement to prevent multiple nodes creating clusters
3. Exit

⁠To consider

List of things I want to implement:

• TLS authentication
• Automatic snapshot to an S3 bucket
• Automatic recovery if building a new cluster

⁠References

• https://github.com/etcd-io/etcd⁠
• https://pkgs.alpinelinux.org/packages⁠