How do I set ulimit for containers in Kubernetes?

Question

How do I set ulimit for containers in Kubernetes? (specifically ulimit -u)

Answer 1

Considering Docker is designed for single processes for the most part ulimit -u doesn't exactly make sense. However, if you are looking for resource limiting in general, Kubernetes allows you to set a quota on a resource. Here are the docs: https://github.com/kubernetes/kubernetes/blob/release-1.0/docs/admin/resource-quota.md. This way you specify number of cores/memory/disk usage.

Answer 2

If you are able to ssh into the kubernetes cluster, you can modify the docker.service file.

• For an amazon EKS cluster, the file is located at /usr/lib/systemd/system/docker.service.

• Append the property LimitMEMLOCK=Infinity in the file and then restart the docker service.

  sudo service docker restart

This would spin up docker containers with an infinite memlock value. Probably equivalent to

docker run -ulimit memlock=-1:-1 <docker image>

Answer 3

In Kubernetes cluster (AWS EKS) you can change the ulimit for a docker container by modifying the /etc/docker/daemon.json in the node where your container is running.

Add following lines to /etc/docker/daemon.json

"default-ulimits": { "nofile": { "Name": "nofile", "Hard": 128000, "Soft": 128000 } }

and finally restart the docker service on that node by executing following command.

service docker restart

Answer 4

It appears that you can't currently set a ulimit but it is an open issue: https://github.com/kubernetes/kubernetes/issues/3595