nginx: host not found in upstream

Hello, I’m going through this tutorial on AWS ECS and I’m at the point where I’m attempting to run docker compose up with the ecs context.

Everything is going well up until it attempts to start the yelb-ui container which results in failure consistently. The error I see in the logs is:

nginx: [emerg] host not found in upstream "yelb-appserver" in /etc/nginx/conf.d/default.conf:5

I’ve googled around and it seems like the consensus is that it’s a startup issue and that yelb-appserver must start before yelb-ui. The solutions suggest to use depends-on, but it would appear that’s already being used in the docker-compose.yaml file. I’m not sure what else to do.

[mreferre]

Mh… now that you mention that I think I remember seeing people having troubles with misconfigured VPC (especially around DNS settings etc because Service Discovery relies on that). Please note that if you create a brand new VPC you’d need to add a parameter to the compose file so that docker uses that VPC instead of the default one.

Use x-aws-vpc as a top-level element in your Compose file to set the ARN of a VPC when deploying a Compose application

From: https://docs.docker.com/cloud/ecs-integration/

[mreferre]

I am closing this. Let me know if you need more help.