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Accepted
Anthony Kong
Asked: 2017-08-25 00:15:09 +0800 CST

ECS cluster has no ecs instances but two ecs instances are visible in EC2

  • 772

I am trying to create a very simple cluster in sydney region.

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It is a very straightforward setup. I specified the harddisk to be 60G. I want to have two ec2 instances in the cluster.

They show up as expected in ec2 panel.

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However the ec2 instances are not showing up in the ecs cluster page:

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1) Why It happens?

2) Is there any logging I can examine to find out the underlying problem?

amazon-ec2

6 Answers

  1. You indicated in your comment that the instances have no public IP addresses. I'm extrapolating from that comment that your instances likely have no route to the Internet as well.

    In order to use ECS, your instances need to have a route to reach (at a minimum) the ECS service endpoints. A route to the Internet can be through an Internet Gateway (IGW), Network Address Translation (NAT), or through an HTTP Proxy. Without a route to reach the ECS service endpoints, the ECS agent will be unable to register itself into your cluster and you will be unable to use those instances with ECS.

    • 11
  2. Best Answer

    Fixed the issue by following the following two steps:

    1) Make sure 'auto-assign public IPv4 address' is enabled

    enter image description here

    2) Create and attached a gateway to the VPC. Then add a route to the gateway.

    enter image description here

    • 4

  3. are you using an ecs optimized ami? i would do that and then include this in your user-data when you spawn the instance

    #!/bin/bash
echo ECS_CLUSTER=your-cluster-name >> /etc/ecs/ecs.config

    if you ssh onto the box, you should be able to see it register with the cluster then in the ecs agent docker logs

    eg.

    [ec2-user@ip-10-0-X-XXX ~]$ docker logs my-ecs-agent-container-id
---snip----
2019-04-23T20:46:19Z [INFO] Registered container instance with cluster!
2019-04-23T20:46:19Z [INFO] Registration completed successfully. I am running as 'arn:aws:ecs:us-west-2:XXXXXXX:container-instance/xxxxx-yyyy-zzz-ddd-12345gdd' in cluster 'your-cluster'
---snip----
    • 4

  4. The issue for me was that the ECS agent was not starting on the EC2 instance. And was seeing the below error in the ecs agent logs at /var/log/ecs/ecs-init.log

    [INFO] Agent exited with code 5
[ERROR] agent exited with terminal exit code

    Following the instructions mentioned here and deleting the json file located at var/lib/ecs/data/ecs_agent_data.json and restarting the ECS agent using the below command is what ultimately worked for me. 

    sudo service docker restart && sudo start ecs
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  5. Another possible reason is using non ECS optimized AMI, also, having no outbounds rules in the security group can block the agent.

    • 0

  6. Choosing the Auto assign public IP -> Enabled worked form me while creating the cluster

    Choosing the Auto assign public IP -> Enabled worked for me

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