带有 ASG 和 ELB (bitbucket) 的 AWS CD/CI 管道

Question

I must first preface by saying I am relatively new to AWS but finding it immensely useful. Let me describe my scenario...

What I have currently

• An Auto scaling group (ASG)
• An Elastic Load Balancer (ELB)
• A CD/CI pipeline using CodeDeploy and Bitbucket
• Node/Express app serving a custom API on EC2 instances
• VPC and su.nets are working well
• An AMI with my app code

My question

When the ASG decides to scale in a new EC2 instance using my launch template and AMI, it will use the application code from the AMI. But if I deploy to master at some point, my AMI will not be updated, but instances within the ASG will be updated. What is the best method for ensuring the new instances spawned by the ASG are running the latest code version (master)?

My initial thoughts

I am thinking to include a bash script in the launch config that will pull the latest code from Bitbucket and run any following steps to get my application running (such as "npm install", "npm run start" etc etc). I'm sure someone has a more elegant solution, and I'd love to hear some suggestions.

Answer 1

To anyone coming to this, I did solve my problem. I was correct initially. The "user data" field within the Launch Template was a good place to bootstrap my app once the instance is up and running. It basically clones from the remote repo and performs any necessary steps to launch the app after that.

For example, in the launch configuration for EC2

#cloud-boothook
#!/bin/bash
git clone myremoterepo.git
cd myremoterepo
npm install
npm run start

Also, if you're running a classic load balancer, CodeDeploy will attempt to start a deployment, based on your latest code repo in S3, when your ASG scales up the EC2 instances. So the above solution will be redundant.

Answer 2

thanks for this post. But it would help me a lot if you shared an example of your bitbucket pipeline yml, since I have a project that migrates it to the asg infrastructure with network load balancer, and I don't know how to configure a code deploy to integrate it with s3 and bitbucket. A guide would help me a lot to be able to configure the entire process of deploying my load balancer from bitbucket.