通过 AWS ECS 服务发现将前端应用程序与后端连接起来

Question

I have a web application that consists of Frontend (built on ReactJS) and Backend (built on Python).

Frontend: I have created a ECS Fargate service and attached aws application load balancer.

Backend: I have created a ECS Fargate service and attached ECS Service discovery.

Now, when I try to make request to the backend via service discovery, the response from backend never came. Here my frontend code snippet:

axios.get("http://be.be:5000/", {"abc":"bcd"})
                    .then(response => {
                        alert(response['data'])
                        console.log(response)
                        return response.data
                    })
                    .catch(error => {
                        console.log(error)

                    })

Here, 'be.be' is the URL provided by AWS ECS service discovery. Instead of "http://be.be:5000/" if I put public of the task like this: "http://public-ip:5000/" it works perfectly.

[Note: I have created an ec2 server on the same VPC and tried to dig +short http://be.be , it works perfectly as well]

What I am missing here?

Answer 1

You can't use service discovery (SD) names over the Internet from your front-end. They are only usable within a VPC, not from the outside. This is because SD uses only private IP addresses which can't be used over the internet. From docs :

The DNS records created for a service discovery service always register with the private IP address for the task, rather than the public IP address, even when public namespaces are used.

For traffic over the internet, you have to use your load balancer.