CODEWITHSUNDEEP
amazon-web-servicesamazon-ec2amazon-elbamazon-elastic-beanstalk
supersan
supersan

Reputation: 6181

How to connect to specific instance behind Elastic Load Balancer

I'm deploying my app via Elastic Beanstalk, which creates and Elastic load balancer and puts all my instances behind it (3 or more).

Is there a way to contact each of these instances directly? I want to trigger a specific command on each instances (git pull command to synchronize with the latest code in my remote repo).

I have the list of IP address and public DNS of the instances from PHP SDK but since the firewalls rules restricts the source of IP address to the elastic load balancer IP on port 80, I can't seem to access them directly.

Is there a way around it?

P.S. The SSH port seems to open for all traffic, but how can I create a trigger with that? I'm hoping to create a PHP script to automate this with a webhook on the remote repo.

Upvotes: 1

Views: 712

Answers (2)

dotcomly
dotcomly

Reputation: 2214

I highly suggest you use the EB CLI with git integration for all deployments, no matter how small. It is great because you can map a git branch to an environment with eb use YOUR_ENV then when you run eb deploy with that branch checked out it will deploy to that environment.

There is a lot of work involved in ensuring multiple servers pull the correct code and everything is working as expected. What if a server is in the processes of spinning up but is not ready for SSH so your script skips it and it does not get the new code?

Also, what happens when a new server spins up but it is using the old application because that's what is in EB? You could have your kickstart do a git pull but then what happens when you are not ready to push, a new server starts and is alone with the new code?

I could probably find 5 more edge cases without breaking a sweat. Look into eb deploy, you will be happy you did.

Upvotes: 3

Edward Samuel Pasaribu
Edward Samuel Pasaribu

Reputation: 3968

You need to setup a CI (or make a simple web service) and create a webhook in your repository. Your CI need to get all instances under your Elastic Beanstalk environment and then call git pull via SSH.

Or, just create a cron job in your all instances via .ebxensions script.

I thought it's not a good practice in Elastic Beanstalk to run git pull in order to synchronize your app with your git repo. Because, it misused the Application Version semantic meaning. Sometimes, you can't determine which app version are in your instances from Application Version. It's better to create a new Application Version in Elastic Beanstalk to deploy a new app version.

If you host your repo in Github, you can take a look into CodeDeploy.

Upvotes: 2

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