Add procedure for Corosync-qnet (#366)

Hacky but working solution...

Author: Antiz96

Services/Corosync-qnetd.md

@@ -0,0 +1,84 @@
+# Corosyn-qnet
+
+I'm running this inside a Debian container on my Alpine's Raspberry PI server to act as a third / external node for my Proxmox cluster.  
+See <https://pve.proxmox.com/wiki/Cluster_Manager#_corosync_external_vote_support>.
+
+**Warning:** This solution works but is kinda hacky...
+
+## Install Docker on my Server (if not done already)
+
+<https://github.com/Antiz96/Linux-Server/blob/main/Services/Docker.md>
+
+## Set up ssh connection with the proxmox nodes
+
+```bash
+sudo -e /etc/ssh/sshd_config
+```
+
+> [...]  
+> PermitRootLogin prohibit-password  
+> [...]
+
+```bash
+sudo rc-service sshd restart
+```
+
+Proceed to SSH key exchange with every nodes (for the `root` user).  
+Set `~/.ssh/config` if needed.
+
+## Setup the Debian container
+
+```bash
+sudo docker run -dit --restart=unless-stopped --network host --hostname debian --name debian debian:bookworm-slim bash # Pull and run a Debian container
+sudo docker exec -it debian bash # Enter the container
+apt update && apt install corosync-qnetd # Install the corosync-qnetd package
+exit # Exit the container
+sudo docker commit debian qnetd:latest # Commit the container as a custom image
+sudo docker rm -f debian # Delete the Debian container
+sudo docker run -dit --restart=unless-stopped --network host --hostname qnetd --name qnetd qnetd corosync-qnetd -f # Run the custom container once to retrieve the corosync files from the host
+sudo docker cp qnetd:/etc/corosync /etc/ # Copy the needed corosync files to host
+sudo docker rm -f qnetd # Delete the container
+sudo docker run -dit --restart=unless-stopped --network host -v /etc/corosync:/etc/corosync -v /tmp:/tmp --hostname qnetd --name qnetd qnetd corosync-qnetd -f # Run the custom container with the proper volume mapping
+sudo docker image prune -a # Remove dangling image
+```
+
+## Setup cluster node
+
+On the QDEVICE node:
+
+```bash
+sudo vim /usr/local/bin/corosync-qnetd-certutil
+```
+
+> #!/bin/bash  
+> docker exec -i qnetd corosync-qnetd-certutil "$@"
+
+```bash
+sudo chmod +x /usr/local/bin/corosync-qnetd-certutil
+```
+
+On **every** Proxmox (PVE) nodes:
+
+```bash
+sudo apt install corosync-qdevice
+```
+
+From **one** of the Proxmox (PVE) nodes:
+
+```bash
+sudo pvecm qdevice setup <QDEVICE-IP> # **Warning:** This command expects **all** nodes to use the default 22 SSH port
+```
+
+You can check that all the steps have successfully completed with:
+
+```bash
+sudo pvecm status
+```
+
+## Update
+
+```bash
+sudo docker exec -it qnetd bash # Enter the container
+apt update && apt full-upgrade && apt autoremove # Update the system
+exit # Exit the container
+```

Services/Docker.md

@@ -9,6 +9,16 @@ sudo pacman -S docker
 sudo systemctl enable --now docker containerd
 ```
 
+## Install Docker on Alpine
+
+```bash
+sudo apk add docker
+sudo rc-update add docker
+sudo rc-update add containerd
+sudo rc-service docker start
+sudo rc-service containerd start
+```
+
 ## Install Docker on Debian
 
 <https://www.linode.com/docs/guides/installing-and-using-docker-on-ubuntu-and-debian/>

Services/README.md

@@ -38,3 +38,4 @@ This is a (non-exhaustive) list of installation and configuration procedures of
 - [Uptime Kuma - Uptime monitoring](https://github.com/Antiz96/Linux-Server/blob/main/Services/Uptime-Kuma.md)
 - [Homepage - Dashboard](https://github.com/Antiz96/Linux-Server/blob/main/Services/Homepage.md)
 - [Shlink - URL Shortener](https://github.com/Antiz96/Linux-Server/blob/main/Services/Shlink.md)
+- [Corosync-qnetd - Corosync qdevice external voter for Proxmox cluster](https://github.com/Antiz96/Linux-Server/blob/main/Services/Corosync-qnetd.md)