Increase open file limit in the VM / inside containers

Report on user-slack: https://rancher-users.slack.com/archives/C0200L1N1MM/p1633033996169800

pod ulimits are too low for my use case. Specifically open files. Any recommended way to increase it?

Default setting for ulimit -n is 1024, same as in most distros. Should we increase it?

[jandubois]

Since nobody indicated which platform they are using, I’m just assuming macOS (or Linux) now. If you are on Windows, this will not work:

Create an ~/Library/Application Support/rancher-desktop/lima/_config/override.yaml file with a provisioning script:

provision:
- mode: system
  script: |
    #!/bin/sh
    cat <<'EOF' > /etc/security/limits.d/rancher-desktop.conf
    * soft     nofile         82920
    * hard     nofile         82920
    EOF

Stop and restart Rancher Desktop, and you should have updated limits in your containers. I’ve verified this with RabbitMQ; after the restart the container started up automatically.

I’ve also checked the dockerd configuration, which seems to have a larger nofile limit by default.

[jandubois]

Thx @jandubois this workarround works for Elasticsearch, too @stephenpope

I thought for Elastic you also had to increase the vm.max_map_count setting. So for anybody else finding this issue, add

sysctl -w vm.max_map_count=262144

to the provisioning script if you need to update the count for Elastic.