Can I set ulimit for containers in k8s

Question

Any way i can set ulimit for containers in kubernetes?

Answer 1

Since we use docker mostly for single processes, so there hasn't been an actual need for ulimit -u on it. On the other hand if you're just looking for resource limiting, kubernetes lets you do that. You can follow this doc:

https://github.com/kubernetes/kubernetes/blob/release-1.0/docs/admin/resource-quota.md

Answer 2

ssh into your Kubernetes cluster and 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 docker using the following command

sudo service docker restart

This will spin up docker containers with an infinity memlock which is equivalent to

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

Answer 3

You can set a DaemonSet with a privileged container setting the hosts ulimit. Something like this:

Example:

    image: image-name
    command: ["sh", "-c", "ulimit -n 65536"]
    securityContext:
      privileged: true

Answer 4

You can either modify them via UserData for worker AutoScalingGroup (when using EKS AMI) or by building your own AMI.

Something like:

sudo sed -i "s|ExecStart=.*|ExecStart=/usr/bin/dockerd --default-ulimit memlock=83968000:83968000|g" /usr/lib/systemd/system/docker.service

sudo systemctl restart docker.service