linux.rst

Deploying a Linux-based CI

This document contains instructions to build and deploy a new bare-OS CI for Linux. Instructions for deployment assume a freshly installed machine, with Idiap's latest Debian distribution running. Our builds use Docker images. We also configure docker-in-docker to enable to run docker builds (and other tests) within docker images.

Warning

Idiap has throttling rules that are typically applied to all machines in the lab network. To avoid issues for newly installed CI nodes, ensure you request throttling to be disabled for new CI machines.

Docker and Gitlab-runner setup

Base docker installation: https://secure.idiap.ch/intranet/system/software/docker

Ensure to add/configure for auto-loading the overlay kernel module in /etc/modules. Then update/create /etc/docker/daemon.json to contain the entry "storage-driver": "overlay2".

To ensure that you can control memory and CPU usage for launched docker containers, you'll need to enable "cgroups" on your machine. In essence, change /etc/default/grub to contain the line GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1". Then, re-run update-grub after such change.

To install docker at Idiap, you also need to follow the security guidelines.

If you do not follow these guidelines, the machine will not be accessible from outside via the login gateway, as the default docker installation conflicts with Idiap's internal setup. You may also find other network connectivity issues.

Also, you want to place /var/lib/docker on a fast disk. Normally, we have a scratch partition for this. Follow the instructions at https://linuxconfig.org/how-to-move-docker-s-default-var-lib-docker-to-another-directory-on-ubuntu-debian-linux for this step:

  $ mkdir /scratch/docker
  $ chmod g-rw,o-rw /scratch/docker
  $ service docker stop
  $ rsync -aqxP /var/lib/docker/ /scratch/docker
  $ rm -rf /var/lib/docker
  $ vim /etc/docker/daemon.json  # add data-root -> /scratch/docker
  $ service docker start


Reboot the machine to ensure everything works fine.

Hosts section

We re-direct calls to www.idiap.ch to our internal server, for speed. Just add this to /etc/hosts:

$ echo "" >> /etc/hosts
$ echo "#We fake www.idiap.ch to keep things internal" >> /etc/hosts
$ echo "What is the internal server IPv4 address?"
$ read ipv4add
$ echo "${ipv4add} www.idiap.ch" >> /etc/hosts
$ echo "What is the internal server IPv6 address?"
$ read ipv6add
$ echo "${ipv6add} www.idiap.ch" >> /etc/hosts

Note

You should obtain the values of the internal IPv4 and IPv6 addresses from inside the Idiap network. We cannot replicate them in this manual for security reasons.

Gitlab runner configuration

Once that is setup, install gitlab-runner from https://docs.gitlab.com/runner/install/linux-repository.html, and then register it https://docs.gitlab.com/runner/register/.