I'm having a tough time with my ECS Fargate setup that's running in private subnets. My tasks keep failing to start, and I'm getting this error:
`ResourceInitializationError: unable to pull secrets or registry auth: unable to retrieve secret from asm: There is a connection issue between the task and AWS Secrets Manager. Check your task network configuration...`
I've already done a thorough check of my configuration:
- All necessary VPC interface endpoints (Secrets Manager, ECR API, ECR Docker, CloudWatch) are created and available, linked to the correct private subnets.
- The endpoints share a security group with my ECS tasks, allowing inbound 443 from itself and outbound 443 to 0.0.0.0/0.
- The S3 Gateway endpoint is present, linked properly to the route table associated with my ECS subnets.
- Network ACLs are wide open (allowing all inbound and outbound traffic).
- VPC DNS support and hostnames are enabled.
- IAM roles are configured: the task role has SecretsManagerReadWrite, and the execution role has AmazonECSTaskExecutionRolePolicy and SecretsManagerReadWrite permissions.
- Route tables and subnet associations are accurate.
- I've tried recreating endpoints and redeploying the service.
The error occurs before my container command even starts running. I'm feeling pretty stuck at this point and would greatly appreciate any insights or suggestions you all might have! Thanks a bunch!
4 Answers
Double-check if outbound requests from your ECS tasks are allowed. If you've opened everything and still face issues, it might be worth reviewing the security group rules overall. What did you set your outbound rules to?
Consider enabling VPC flow logs for more visibility on traffic. Additionally, check if you need to open ephemeral ports for outbound traffic to the VPC endpoints from your ECS cluster. That might help with the connection issue!
I checked the NACLs, and they're not restrictive, plus I'm allowing [0.0.0.0](http://0.0.0.0) for in/outbound. I’ll enable flow logs to gather more data. By the way, I noticed that Service Discovery isn't set up in my cluster—is that relevant for VPC endpoints?
Have you thought about adjusting the security group settings? Allowing only outbound 443 traffic might be restricting communication. Try expanding the inbound and outbound rules temporarily to see if that resolves the issue. Once you find the root cause, you can tighten the rules again to maintain security.
I used to think that ECS only needed outbound on 443 to reach VPC endpoints. But you're right; it makes sense to open things up while troubleshooting. I'll give that a shot!
To enable ECS to access other services, ensure they’re in a public subnet or have a VPC Endpoint. Private subnets can't connect to the internet or many AWS services alone. I noticed you have the endpoint services set—just make sure you're using the right VPC Endpoint DNS when accessing Secrets Manager, as the default may not work!
I ended up changing the outbound rule to allow HTTPS to 0.0.0.0 everywhere. I can post the CLI rules tomorrow if needed!