How to install ESXi on a Hetzner dedicated server with Rescue access

How to install ESXi on a server that only has Rescue access?

This step-by-step, technical guide explains how to install ESXi on a Hetzner dedicated server when there is no KVM/VNC access from the datacenter and your only tool is «Rescue Access.» It is designed for server administrators, DevOps teams, and virtualization professionals and includes Linux commands, practical scenarios, UEFI/Legacy tips, drivers, networking, datastore, and security recommendations.

Prerequisites and initial review

Before starting the installation, do the following to reduce the chance of problems during the installation process.

• Activating Rescue in the Hetzner panel: Select the rescue type (linux64) and reboot the server. Hetzner will provide the SSH login information to rescue.
• SSH connection to Rescue: Connect to the server from the local machine.

ssh root@IP_SERVER

Check disks and network/RAID hardware:

fdisk -l
lsblk
lspci | egrep -i 'nic|ethernet|raid|sas|nvme'

Check the UEFI status if possible:

efibootmgr -v

Loading and verifying the ESXi ISO: Download from VMware or upload the ISO from a local machine with SCP and check the checksum.

wget -O /root/esxi.iso "https://path/to/VMware-ESXi.iso"
# یا از ماشین محلی
scp VMware-ESXi.iso root@IP:/root/

sha256sum /root/esxi.iso

Method 1 — Simple and common: Write (dd) the ISO directly to disk

This is the fastest way and often works in a non-KVM environment. The idea is to burn the installer ISO to the hard drive as bootable media and reboot the server to boot from that ISO.

Steps

1. Upload or download ISO to Rescue: (Example above)
2. Checksum check: (Example above)
3. Identify the destination disk: Let's assume /dev/sda.

lsblk

Writing ISO to disc (Warning: all contents will be erased):

dd if=/root/esxi.iso of=/dev/sda bs=4M status=progress conv=fsync
sync

reboot

If it doesn't boot: Use alternative methods such as EFI or iPXE extraction.

Method 2 — Extract EFI and record boot entry (writeable if UEFI)

If the server supports UEFI and dd doesn't work, you can put the contents of the EFI ISO on a FAT32 partition and create a boot entry with efibootmgr.

Summary steps

parted /dev/sda mklabel gpt
parted /dev/sda mkpart primary fat32 1MiB 200MiB
mkfs.vfat -n ESXI_BOOT /dev/sda1

mkdir /mnt/iso /mnt/esp
mount -o loop /root/esxi.iso /mnt/iso
mount /dev/sda1 /mnt/esp
cp -r /mnt/iso/efi /mnt/esp/EFI/BOOT
sync

efibootmgr -c -d /dev/sda -p 1 -L "ESXi Installer" -l '\EFI\BOOT\BOOTX64.EFI'

reboot

Method 3 — Advanced Solution: iPXE/HTTP boot (if needed)

If you need more control or want to boot from the installer over the network, you can run a simple iPXE in Rescue, extract the kernel and initrd from the ISO, and boot over HTTP. This method requires knowledge of iPXE/HTTP and extracting boot files from the ISO, and is more complex, but it is doable in a non-KVM environment.

The advantage of iPXE is that you don't need to write directly to disk and you can set kernel parameters dynamically; but you need to extract the appropriate files (kernel + initrd) from the ISO and set up an HTTP server in Rescue.

Key points when installing ESXi on a Hetzner server

• NIC Driver: Common network cards like Intel X520 and X710 are usually supported; some Realtek or Broadcom may require a VIB or community driver. Before installing, check the VMware hardware compatibility list for your version of ESXi.
• RAID/HBA Controller: Depending on the model (LSI, Broadcom, Adaptec) a separate driver may be required. For servers with software control (FakeRAID) it is preferable to use passthrough disks or use NAS/SAN with iSCSI/NFS for datastore.
• Secure Boot: Some versions of ESXi are compatible with Secure Boot, but the installation may require that Secure Boot be disabled. If you are unable to configure the BIOS, check to see if Secure Boot is enabled.
• Disk capacity and type for datastore: For production environments, use NVMe or SAS with hardware RAID, or use NAS/SAN with iSCSI/NFS for datastore.
• Permissions: It is possible to install ESXi in evaluation mode, but you need a license for long-term use.

Basic configuration after installation (ESXi commands)

After booting ESXi and logging into DCUI or SSH access, the basic commands to configure network management, enable SSH, and add a datastore are as follows.

esxcli network firewall ruleset set -e true -r sshServer
/etc/init.d/SSH start

esxcli network ip interface ipv4 set -i vmk0 -I 203.0.113.10 -N 255.255.255.0 -t static
esxcli network ip route ipv4 set --gateway 203.0.113.1

esxcli storage filesystem list
esxcli storage nfs add -H nfs-server.example.com -s /export/esxi -v NFS-DATASTORE

esxcli software vib install -v /tmp/driver.vib

Note: Some versions of ESXi do not use systemctl and services are managed by scripts in /etc/init.d.

Security and operational tips

Important recommendations: Enable the ESXi firewall and restrict administrative access. Use Lockdown Mode to protect the DCUI and restrict the root account if possible.

• Monitoring: Track NIC and SMART disk health and send ESXi logs to a central syslog server.
• Backup: Have a backup strategy for virtual machines and host configuration (export config) to enable quick recovery in case of failure.

Boot Testing and Troubleshooting (Checklist)

• Enter Rescue and check that the boot disk is detected (lsblk, blkid).
• Check dmesg output and UEFI logs (if possible).
• If the NIC driver is the problem, test the network connection with a compatible network card or use alternative network settings.
• If dd fails to boot, try the EFI extraction or iPXE method.

Comparing location/services and infrastructure benefits associated with ESXi deployments

• Global locations: Ability to place ESXi machines or backup storage in a geographical location close to users or target data centers to reduce latency.
• GPU Servers: If you need to passthrough GPU cards for AI or rendering, servers with VT-d and SR-IOV support are available.
• DDoS protection and BGP network: Suitable for hosting availability-sensitive VMs such as trading or gaming.
• Complementary services: It is possible to use a VPS to manage your network, CDN, DNS, and related services to optimize performance and availability.

Conclusion and final recommendations

Installing ESXi on a Hetzner dedicated server is entirely possible with Rescue access alone, but it requires caution, backups, and awareness of UEFI/BIOS status and driver compatibility. dd method It's the easiest way, but if it doesn't boot, use EFI or iPXE-based methods. Keep security, backups, and driver compatibility testing in mind at every step.

Support services and compatibility checks

If you need to check hardware compatibility with the ESXi version, configure the network, or help implement alternative methods, we can review and provide technical guidance to ensure installation and setup is completed with minimal risk.

Frequently Asked Questions