Hi,

We are running Jenkins with ECS cloud, meaning the agents are docker based agents.

Some of our pipelines are using image.inside to run arbitrary build tools which are not part of the slave images.

Before upgrading to amazon-ecs-agent-1.16.0 we got the following message in the log files:

ecs-cloud-33394f9575f0e2 seems to be running inside container 01b572fc3c671c11087fcb8166d686792d2b725e570af941b37ff3f28986762f 

After the upgrade, we get:

ecs-cloud-dc46d9e888c4 does not seem to be running inside a container

Looking at The DockerClient code I see that the way the plugin understands it is running within docker container, is by matching docker cgroups pattern with the default hierarchy name docker.

The problem is that AWS ECS changed their default hierarchy to be ecs

root@20f3571647fc:/usr/local/tomcat# cat /proc/self/cgroup
 9:perf_event:/ecs/0410eff2-7e59-4111-823e-1e0d98ef7f30/20f3571647fc2a6c718909b85f2bfd79ffae4f6afe8c8121c8b8415f0619f013
 8:memory:/ecs/0410eff2-7e59-4111-823e-1e0d98ef7f30/20f3571647fc2a6c718909b85f2bfd79ffae4f6afe8c8121c8b8415f0619f013
 7:hugetlb:/ecs/0410eff2-7e59-4111-823e-1e0d98ef7f30/20f3571647fc2a6c718909b85f2bfd79ffae4f6afe8c8121c8b8415f0619f013
...

Because of that, image.inside step stopped working and we get the following error each build.

sh: can't create /var/jenkins_home/workspace/...@tmp/durable-9cddf800/jenkins-log.txt: nonexistent directory

I believe a quick fix would be to change the regex to match ecs as well, or add a cgroups hierarchy configuration parameter to the plugin.

Best regards,

Ohad