So it’s been a while since I started this job in a big corporation. I always enjoy new challenges, now my wish got granted. Not in a very good way.

The things work in a quite different manner here. There are big silos and layers between teams and departments, so the challenges here are not quite technical in nature. How unexpected this is.

Still there are lots of things can be improved with technology, here’s one example. When I was migrating an old web application stack from on-premises infrastructure to AWS, the AWS landing zone has already been provisioned with a duo-VPC setup. I really really miss the days that working with Kubernetes clusters and I can just run kubectl exec -ti ... and get a terminal session quickly.

Now things look like year 2000 and I need to use SSH proxy command again, without old school static IP addresses though. Ansible dynamic inventory is quite handy in most cases but it failed due to some unknown corporate firewall rules. I still have bash, aws-cli and jq, so this is my handy bash script to connect to 1 instance of an auto scaling group, via a bastion host(they both can be rebuilt and change IP).

#!/bin/bash
function get_stack_ip(){
  aws ec2 describe-instances \
    --fileter "Name=tag-key,Values=aws:cloudformation:stack-name" "Name=tag-value,Values=$1" \
    |jq '.Reservations[] |select(.Instance[0].PrivateIpAddress != null).Instance[0].PrivateIpAddress' \
    |tr -d '"'
}

Then it’s easy to use this function to get IPs of the bastion stack and the target stack, such as:

IP_BASTION=$(get_stack_ip bastion_stack)
IP_TARGET=$(get_stack_ip target_stack)
ssh -o ProxyCommand="ssh user@IP_BASTION nc %h %p" user@IP_TARGET

🙂