Add Linux installation instructions

ci-install/README.md

+# Instructions for CI machine installation
+
+This directory contains instructions for CI machine installation from sources.

ci-install/linux/README.md

+# Deploying a Linux-based CI for Bob
+
+This document contains instructions to build and deploy a new bare-OS CI for
+Linux.  Instructions for deployment assume a freshly installed machine, with
+Debian 9.x running.  Our builds use Docker images.  We also configure
+docker-in-docker to enable to run docker builds (and other tests) within docker
+images.
+
+
+## Docker and Gitlab-runner setup
+
+Just follow the advices from: https://medium.com/@tonywooster/docker-in-docker-in-gitlab-runners-220caeb708ca
+
+
+### Hosts section
+
+We re-direct calls to www.idiap.ch to our internal server, for speed.  Just add
+this to `/etc/hosts`:
+
+```sh
+echo "" >> /etc/hosts
+echo "#We fake www.idiap.ch to keep things internal" >> /etc/hosts
+echo "172.31.100.235 www.idiap.ch" >> /etc/hosts
+echo "2001:620:7a3:600:0:acff:fe1f:64eb www.idiap.ch" >> /etc/hosts
+```
+
+
+### Gitlab runner configuration
+
+We are currently using this:
+
+```text
+concurrent = 4
+check_interval = 10
+
+[[runners]]
+  name = "docker"
+  output_limit = 102400
+  url = "https://gitlab.idiap.ch/ci"
+  token = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+  executor = "docker"
+  limit = 4
+  builds_dir = "/local/builds"
+  cache_dir = "/local/cache"
+  [runners.docker]
+    tls_verify = false
+    image = "python:latest"
+    privileged = false
+    disable_cache = false
+    volumes = ["/local/cache"]
+    extra_hosts = ["www.idiap.ch:172.31.100.235"]
+
+[[runners]]
+  name = "docker-build"
+  output_limit = 102400
+  executor = "shell"
+  shell = "bash"
+  url = "https://gitlab.idiap.ch/ci"
+  token = "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+  limit = 4
+  builds_dir = "/local/builds"
+  cache_dir = "/local/cache"
+```
+
+
+## Crontabs
+
+```sh
+# crontab -l
+MAILTO=""
+@reboot /root/docker-cleanup-service.sh
+0 0 * * * /root/docker-cleanup.sh
+```
+
+The `docker-cleanup-service.sh` is:
+
+```sh
+#!/usr/bin/env sh
+
+# Continuously running image to ensure minimal space is available
+
+docker run -d \
+    -e LOW_FREE_SPACE=30G \
+    -e EXPECTED_FREE_SPACE=50G \
+    -e LOW_FREE_FILES_COUNT=2097152 \
+    -e EXPECTED_FREE_FILES_COUNT=4194304 \
+    -e DEFAULT_TTL=60m \
+    -e USE_DF=1 \
+    --restart always \
+    -v /var/run/docker.sock:/var/run/docker.sock \
+    --name=gitlab-runner-docker-cleanup \
+    quay.io/gitlab/gitlab-runner-docker-cleanup
+```
+
+The `docker-cleanup.sh` is:
+
+```sh
+#!/usr/bin/env sh
+
+# Cleans-up docker stuff which is not being used
+
+# Exited machines which are still dangling
+#Caches are containers that we do not want to delete here
+#echo "Cleaning exited machines..."
+#docker rm -v $(docker ps -a -q -f status=exited)
+
+# Unused image leafs
+echo "Removing unused image leafs..."
+docker rmi $(docker images --filter "dangling=true" -q --no-trunc)
+```

macos-ci/README.rst → ci-install/macos/README.rst

@@ -3,9 +3,7 @@
 ------------------------------------
 
 This document contains instructions to build and deploy a new bare-OS CI for
-macOS.  Instructions for deployment assume a freshly installed machine.  There
-are no requirements on the OS for the host, for as long as it is supported by
-`gitlab runner`_.
+macOS.  Instructions for deployment assume a freshly installed machine.
 
 
 .. note::