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Installing Proxmox VE on a Hetzner dedicated server via the Rescue System

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Installing Proxmox VE on a Hetzner dedicated server via the Rescue System

A Hetzner dedicated root server has no physical/virtual console you can boot an installer ISO from directly (unlike a local machine or a cloud VM with a virtual KVM). Hetzner’s Rescue System — a temporary Linux environment you boot into over the network — combined with running the Proxmox VE installer inside QEMU and viewing it over VNC gives you a way to run the normal graphical installer remotely.

This only applies to a Hetzner dedicated/root server. A Hetzner Cloud VM already boots normally from an ISO you attach in the Cloud Console and doesn’t need this workaround.

Prerequisites

  • A Hetzner Robot account with access to the target server.
  • A VNC client to view the installer.

Steps

1. Boot into the Rescue System

  1. In Hetzner Robot, select the server → Rescue tab → activate the Linux 64-bit rescue variant. You’re given a one-time root password for SSH.
  2. Restart the server (via the OS, or Robot’s Reset tab if it’s unreachable). The Rescue System activation is valid for one boot only, and expires if the server isn’t rebooted within 60 minutes — if it is rebooted later, it boots normally instead.
  3. SSH in as root with the given password: 
    ssh root@<SERVER_IP>

2. Fetch the Proxmox VE ISO

ISO_VERSION=$(curl -s 'http://download.proxmox.com/iso/' | grep -oP 'proxmox-ve_(\d+.\d+-\d).iso' | sort -V | tail -n1)
ISO_URL="http://download.proxmox.com/iso/$ISO_VERSION"
curl $ISO_URL -o /tmp/proxmox-ve.iso

3. Capture the server’s network configuration

You’ll need to re-apply this after installation, since the installer doesn’t know Hetzner’s network setup:

INTERFACE_NAME=$(udevadm info -q property /sys/class/net/eth0 | grep "ID_NET_NAME_PATH=" | cut -d'=' -f2)
IP_CIDR=$(ip addr show eth0 | grep "inet\b" | awk '{print $2}')
GATEWAY=$(ip route | grep default | awk '{print $3}')
IP_ADDRESS=$(echo "$IP_CIDR" | cut -d'/' -f1)
CIDR=$(echo "$IP_CIDR" | cut -d'/' -f2)

4. Boot the installer inside QEMU

PRIMARY_DISK=$(lsblk -dn -o NAME,SIZE,TYPE -e 1,7,11,14,15 | sed -n 1p | awk '{print $1}')
SECONDARY_DISK=$(lsblk -dn -o NAME,SIZE,TYPE -e 1,7,11,14,15 | sed -n 2p | awk '{print $1}')
 
qemu-system-x86_64 -daemonize -enable-kvm -m 10240 \
  -hda /dev/$PRIMARY_DISK \
  -hdb /dev/$SECONDARY_DISK \
  -cdrom /tmp/proxmox-ve.iso -boot d -vnc :0,password -monitor telnet:127.0.0.1:4444,server,nowait
 
echo "change vnc password <VNC_PASSWORD>" | nc -q 1 127.0.0.1 4444

The server’s real disks are passed straight into QEMU as raw block devices, so the installer writes directly to them. Connect a VNC viewer to <SERVER_IP>:5900 with the password you set, and run through the graphical Proxmox VE installer as normal.

5. Stop QEMU after the manual install finishes

printf "quit\n" | nc 127.0.0.1 4444

6. Restart QEMU without the install CD-ROM

qemu-system-x86_64 -daemonize -enable-kvm -m 10240 \
  -hda /dev/$PRIMARY_DISK \
  -hdb /dev/$SECONDARY_DISK \
  -vnc :0,password -monitor telnet:127.0.0.1:4444,server,nowait \
  -net user,hostfwd=tcp::2222-:22 -net nic
 
echo "change vnc password <VNC_PASSWORD>" | nc -q 1 127.0.0.1 4444

A user-mode NIC with a port-forward (2222 → guest port 22) gives you SSH access into the freshly installed system for the next step, without needing to configure real networking inside QEMU.

7. Push the captured network config into the new system

cat > /tmp/proxmox_network_config << EOF
auto lo
iface lo inet loopback
 
iface $INTERFACE_NAME inet manual
 
auto vmbr0
iface vmbr0 inet static
  address $IP_ADDRESS/$CIDR
  gateway $GATEWAY
  bridge_ports $INTERFACE_NAME
  bridge_stp off
  bridge_fd 0
EOF
 
sshpass -p "<ROOT_PASSWORD>" scp -o StrictHostKeyChecking=no -P 2222 /tmp/proxmox_network_config root@localhost:/etc/network/interfaces
sshpass -p "<ROOT_PASSWORD>" ssh -o StrictHostKeyChecking=no -p 2222 root@localhost "sed -i 's/nameserver.*/nameserver 1.1.1.1/' /etc/resolv.conf"

8. Shut down QEMU and reboot into the real install

printf "system_powerdown\n" | nc 127.0.0.1 4444
shutdown -r now

The Rescue System itself reboots, and — since the Rescue activation only applies to one boot — the server comes up from its actual disks into the newly installed Proxmox VE.

Verify

After the reboot, the Proxmox VE web UI should be reachable at https://<YourIPAddress>:8006.

Sources

Graph View

Backlinks