How is "Target Groups" different from "Auto-Scaling Groups" in AWS?

amazon-web-services amazon-ec2 aws-elb
karthiks picture karthiks · Jan 30, 2018 · Viewed 22k times · Source

I'm a little too confused on the terms and its usage. Can you please help me understand how are these used with Load Balancers?

I referred the aws-doc in vain for this :(

Answer

VimalKumar picture VimalKumar · Nov 15, 2018

Target groups are just a group of Ec2 instances. Target groups are closely associated with ELB and not ASG.

  • ELB -> TG - > Group of Instances

We can just use ELB and Target groups to route requests to EC2 instances. With this setup, there is no autoscaling which means instances cannot be added or removed when your load increases/decreases.

  • ELB -> TG - > ASG -> Group of Instances

If you want autoscaling, you can attach a TG to ASG which in turn gets associated to ELB. Now with this setup, you get request routing and autoscaling together. Real world usecases follow this pattern. If you detach the target group from the Auto Scaling group, the instances are automatically deregistered from the target group

Hope this helps.

Related questions

Permission denied (publickey) when SSH Access to Amazon EC2 instance

I want to use my Amazon ec2 instance but faced the following error: Permission denied (publickey). I have created my key pair and downloaded .pem file. Given: chmod 600 pem file. Then, this command ssh -i /home/kashif/serverkey.pem ubuntu@…

Read More
Trying to SSH into an Amazon Ec2 instance - permission error

This is probably a stupidly simple question to some :) I've created a new linux instance on Amazon EC2, and as part of that downloaded the .pem file to allow me to SSH in. When I tried to ssh with: ssh …

Read More
Change key pair for ec2 instance

How do I change the key pair for my ec2 instance in AWS management console? I can stop the instance, I can create new key pair, but I don't see any link to modify the instance's key pair.

Read More