Setting-up-Build-Machines.md

+# Windows Build Machines
+Setting up a Windows build machine consists of a few steps:
+1.  Install the Unreal Engine
+2.  Install the gitlab runner service and register a gitlab runner. Prefereably a shared runner. Use executor `shell`. Use the tags `windows` and `unreal-4.21`(replace version number) for the runner. Make sure to specify a user for the `gitlab-runner install` call, such that the service is not running as admin afterwards.
+3.  Configure the gitlab runner. For this open the config.toml file and add the following lines (change path to unreal engine folder):
+```
+executor = "shell"
+environment = ["UE_ENGINE_FOLDER=F:/UnrealEngine/UE_4.21/Engine"]
+shell = "powershell"
+```
+4.  Start/Restart the gitlab runner service
+
+---
+
+# CentOS Build Machines
+Setting up a CentOS build machine consists of a few steps:
+1.  Set up the gitlab runner according to the instructions of gitlab. Do not register a runner yet.
+2.  Switch to the Gitlab-Runner user account you have created
+3.  Download/Clone the Unreal Engine source code
+4.  Go to the `/Engine/Plugins/Runtime/` and remove the `nDisplay` folder
+5.  In the empty folder clone the nDisplay repository and remove its .git folder with with
+```
+git clone https://devhub.vr.rwth-aachen.de/VR-Group/ndisplay.git ./nDisplay
+rm -rf ./nDisplay/.git
+```
+6.  Go back to the root folder of the downloaded Unreal Engine. Run the following commands to build the engine (will take about 1h):
+`Make sure to NOT run this commands as root. The engine refuses to build as root. Use a less priviledged user instead.`
+```
+./Setup.sh && ./GenerateProjectFiles.sh && make
+```
+7.  Register a gitlab-runner. Preferably a shared runner. Use executor `shell`. Use the tags `centos` and `unreal-4.21` (replace version) for your runner.
+8.  Configure this runner by adding the following lines to the config.toml (locate it by gitlab-runner verify) and replace the path with your engine installation
+```
+environment = ["UE_ENGINE_FOLDER=/home/gitlab-runner/dev/Unreal_4_21/UnrealEngine/Engine"]
+```
+9.  Start/Restart the gitlab runner service
+
+---
+
+# CentOS Deploy Machines
+Setting up a CentOS deploy machine consists of a few steps:
+1.  Set up the gitlab runner according to the instructions of gitlab.
+2.  Register a gitlab-runner. Preferably a shared runner. Use executor `shell`. Use the tags `centos` and `networkdeploy` for your runner.
+3.  Set up ssh keys for the access to the cluster via the following commands
+```
+ssh-keygen -f ~/.ssh/cluster_access_av006de -q -P ""
+ssh-keygen -f ~/.ssh/cluster_access_vrdev -q -P ""
+```
+4.  The generated public keys can be viewed via the following commands. Note them.
+```
+cat ~/.ssh/cluster_access_av006de
+cat ~/.ssh/cluster_access_vrdev
+```
+5.  Append the first key to the `/home/av006de/.ssh/authorized_keys` file on the cluster and the second key to the `/home/vrdev/.ssh/authorized_keys` file.
+6.  To not allow full access to the cluster from the deploy machine, prepend the `vrdev` key in the `authorized_keys` file with the following command:
+```
+command="/home/av006de/bin/rrsync ~/UnrealCIDeploy/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding
+
+it should look like
+
+command="/home/av006de/bin/rrsync ~/UnrealCIDeploy/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAAAB...
+```
+7.  To not allow full access to the cluster from the deploy machine, prepend the `av006de` key in the `authorized_keys` file with the following command:
+```
+command="/home/av006de/bin/rrsync ~/demos_UNREAL/CI/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding
+
+it should look like
+
+command="/home/av006de/bin/rrsync ~/demos_UNREAL/CI/",no-agent-forwarding,no-port-forwarding,no-pty,no-user-rc,no-X11-forwarding ssh-rsa AAAAB...
+```
+8.  Note that the prepend commands are different
+9.  Create a folder directory which is used for syncing with the cluster folder. For this you could use the a structure with `~/dev/unreal_current_deployment/vrdev` and `~/dev/unreal_current_deployment/av006de`.
+10.  Configure the gitlab runner to use this structure by adding the following lines to the config.toml
+```
+environment = ["VRDEV_UNREAL_DEPLOY_FOLDER=/home/gitlab-runner/dev/unreal_current_deployment/vrdev", "CAVE_UNREAL_DEPLOY_FOLDER=/home/gitlab-runner/dev/unreal_current_deployment/av006de"]
+```
+11.  Start/Restart the gitlab runner service
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