Proxmox LXC Create Github Actions Runner

lxc_create_github_actions_runner.sh

#!/usr/bin/env bash

# This script automates the creation and registration of a Github self-hosted runner within a Proxmox LXC (Linux Container).
# The runner is based on Ubuntu 23.04. Before running the script, ensure you have your GITHUB_TOKEN 
# and the OWNERREPO (github owner/repository) available.

# Creates and sets up a self-hosted GitHub Actions runner in an LXC container on Proxmox:

# Create a new LXC container based on ubuntu 23.04
# Installs apt-get dependencies (git, curl)
# Installs docker
# Installs Github actions (needs GITHUB_TOKEN and OWNERREPO) and sets up service
# NOTE: Since the new container has docker support, it cannot be run unpriviledged. This approach is more insecure than using a full-blown VM, at the benefit of being much faster most times. That being said, make sure you only use this self-hosted runner in contexts that you can control at all times (e.g. careful using with public repositories).

# Instructions
# # Download the script
# curl -O https://gist.githubusercontent.com/beautyfree/5eb5c60c5da307612fe0d5fbc332b6c6/raw/lxc_create_github_actions_runner.sh

# # Inspect script, customize variables

# # Run the script
# bash lxc_create_github_actions_runner.sh
# Warning: make sure you read and understand the code you are running before executing it on your machine.

set -e

# Variables
GITHUB_RUNNER_URL="https://github.com/actions/runner/releases/download/v2.333.0/actions-runner-linux-x64-2.333.0.tar.gz"
TEMPL_URL="http://download.proxmox.com/images/system/ubuntu-22.04-standard_22.04-1_amd64.tar.zst"
PCTSIZE="20G"
PCT_ARCH="amd64"
PCT_CORES="4"
PCT_MEMORY="4096"
PCT_SWAP="4096"
PCT_STORAGE="local-lvm"
DEFAULT_IP_ADDR="192.168.0.123/24"
DEFAULT_GATEWAY="192.168.0.1"

# Ask for GitHub token and owner/repo if they're not set
if [ -z "$GITHUB_TOKEN" ]; then
    read -r -p "Enter github token: " GITHUB_TOKEN
    echo
fi
if [ -z "$OWNERREPO" ]; then
    read -r -p "Enter github owner/repo: " OWNERREPO
    echo
fi

# log function prints text in yellow
log() {
  local text="$1"
  echo -e "\033[33m$text\033[0m"
}

# Prompt for network details
# --- Auto-detect network from vmbr0 ---
HOST_IP_CIDR=$(ip -o -f inet addr show vmbr0 | awk '{print $4}')
HOST_IP=$(echo "$HOST_IP_CIDR" | cut -d/ -f1)
CIDR=$(echo "$HOST_IP_CIDR" | cut -d/ -f2)

# Guess gateway (usually .1)
GATEWAY_GUESS=$(ip route | awk '/default/ {print $3}' | head -n1)

# Generate container IP (same subnet, random last octet)
BASE_NET=$(echo "$HOST_IP" | awk -F. '{print $1"."$2"."$3}')
RANDOM_OCTET=$(( (RANDOM % 200) + 50 ))
DEFAULT_IP_ADDR="$BASE_NET.$RANDOM_OCTET/$CIDR"
DEFAULT_GATEWAY="${GATEWAY_GUESS:-$BASE_NET.1}"

echo
echo "Detected network:"
echo "  Host IP:        $HOST_IP"
echo "  Suggested CT IP: $DEFAULT_IP_ADDR"
echo "  Suggested GW:    $DEFAULT_GATEWAY"
echo

# Prompt user with defaults
read -r -e -p "Container Address IP (CIDR format) [$DEFAULT_IP_ADDR]: " input_ip_addr
IP_ADDR=${input_ip_addr:-$DEFAULT_IP_ADDR}

read -r -e -p "Container Gateway IP [$DEFAULT_GATEWAY]: " input_gateway
GATEWAY=${input_gateway:-$DEFAULT_GATEWAY}

# Get filename from the URLs
TEMPL_FILE=$(basename $TEMPL_URL)
GITHUB_RUNNER_FILE=$(basename $GITHUB_RUNNER_URL)

# Get the next available ID from Proxmox
PCTID=$(pvesh get /cluster/nextid)

# Download Ubuntu template
log "-- Downloading $TEMPL_FILE template..."
curl -q -C - -o "$TEMPL_FILE" $TEMPL_URL

# Create LXC container
log "-- Creating LXC container with ID:$PCTID"
pct create "$PCTID" "$TEMPL_FILE" \
   -arch $PCT_ARCH \
   -ostype ubuntu \
   -hostname github-runner-proxmox-$(openssl rand -hex 3) \
   -cores $PCT_CORES \
   -memory $PCT_MEMORY \
   -swap $PCT_SWAP \
   -storage $PCT_STORAGE \
   -features nesting=1,keyctl=1 \
   -net0 name=eth0,bridge=vmbr0,gw="$GATEWAY",ip="$IP_ADDR",type=veth

# Resize the container
log "-- Resizing container to $PCTSIZE"
pct resize "$PCTID" rootfs $PCTSIZE

# Start the container & run updates inside it
log "-- Starting container"
pct start "$PCTID"
sleep 10
log "-- Running updates"
pct exec "$PCTID" -- bash -c "apt update -y && apt install -y git curl zip && passwd -d root"

# Install Docker inside the container
log "-- Installing docker"
pct exec "$PCTID" -- bash -c "curl -qfsSL https://get.docker.com | sh"

# Get runner installation token
log "-- Getting runner installation token"
RES=$(curl -s -L -X POST \
  -H "Accept: application/vnd.github+json" \
  -H "Authorization: Bearer $GITHUB_TOKEN"  \
  -H "X-GitHub-Api-Version: 2022-11-28" \
  https://api.github.com/repos/$OWNERREPO/actions/runners/registration-token)

RUNNER_TOKEN=$(echo $RES | grep -o '"token": "[^"]*' | grep -o '[^"]*$')

if [ -z "$RUNNER_TOKEN" ]; then
  echo "ERROR: Failed to get GitHub runner token. Check GITHUB_TOKEN and OWNERREPO."
  echo "Response was: $RES"
  exit 1
fi

# Install and start the runner
log "-- Installing runner"
pct exec "$PCTID" -- bash -c "mkdir actions-runner && cd actions-runner &&\
    curl -o $GITHUB_RUNNER_FILE -L $GITHUB_RUNNER_URL &&\
    tar xzf $GITHUB_RUNNER_FILE &&\
    RUNNER_ALLOW_RUNASROOT=1 ./config.sh --unattended --url https://github.com/$OWNERREPO --token $RUNNER_TOKEN &&\
    ./svc.sh install root &&\
    ./svc.sh start"

# Delete the downloaded Ubuntu template
rm "$TEMPL_FILE"

Instructions
Download the script

curl -O https://gist.githubusercontent.com/beautyfree/5eb5c60c5da307612fe0d5fbc332b6c6/raw/lxc_create_github_actions_runner.sh

Inspect script, customize variables
Run the script

GITHUB_TOKEN=token OWNERREPO=owner/project bash lxc_create_github_actions_runner.sh

Warning: make sure you read and understand the code you are running before executing it on your machine.