Installing RHEL 9 on Synology Virtual Machine Manager (The Easy Way)

If you tried installing RHEL 9 on Synology VMM, you probably hit this nightmare:

• Installer freezes

• waiting for multipath siblings of sda

• Kernel panic

• “Unable to mount root fs”

• Black screen forever

I spent hours figuring this out. This guide will save you that pain and help you create a Golden Template so you only install once and clone forever.

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Why RHEL Fails on Synology VMM

Synology VMM uses simplified KVM virtualization.
RHEL assumes enterprise SAN storage and enables multipath disk detection by default.

Synology presents a single virtual disk → RHEL thinks it’s a SAN disk → installer waits forever for extra disk paths → boot fails.

The fix is simple once you know it.

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Step 1 — Create the VM with Correct Settings

Create a new VM in Synology Virtual Machine Manager.

Use these settings:

General

• OS Type: Linux

• Version: Other Linux

CPU & Memory

• CPU: 2 vCPU minimum (4 recommended)

• RAM: 4 GB minimum (8 GB ideal)

Boot Mode (IMPORTANT)

• Use BIOS / Legacy

• Do NOT use UEFI

Disk

• Bus: VirtIO

• Size: 40–60 GB

Network

• Adapter: VirtIO

Attach the RHEL 9 ISO and start the VM.

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Step 2 — Fix the Boot Parameters (Critical Step)

When the installer menu appears:

Install Red Hat Enterprise Linux 9.x
Test this media & install
Troubleshooting

Press TAB.

You will see a boot line ending with:

quiet

Append this to the end of the line:

inst.text rd.multipath=0 nomodeset console=tty0

Press ENTER to boot.

This disables multipath detection and forces the text installer, which works perfectly in Synology VMM.

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Step 3 — Start the Installer

You will be prompted with two options:

• Start VNC

• Start Text Mode

Choose:

Start Text Mode

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Step 4 — Choose Installation Type

Select:

Server

This gives you a lightweight but fully usable enterprise server install.

Proceed with automatic partitioning and complete the installation.

Reboot when finished.

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Step 5 — First Login Setup

After the first login, run the following commands.

Update the OS

sudo dnf update -y
sudo reboot

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Install Synology VM integration

This allows clean shutdown and proper VM monitoring.

sudo dnf install qemu-guest-agent -y
sudo systemctl enable --now qemu-guest-agent

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Remove multipath permanently

sudo dnf remove device-mapper-multipath -y

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Install common admin tools

sudo dnf install -y vim wget curl net-tools bash-completion git unzip

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Step 6 — Prepare the VM to Become a Template ⭐

Before converting the VM into a template, clean machine identity.

Run:

sudo truncate -s 0 /etc/machine-id
sudo rm -f /var/lib/dbus/machine-id
sudo rm -f /etc/ssh/ssh_host_*
sudo rm -f /var/lib/systemd/random-seed

Shutdown the VM:

sudo shutdown now

Do NOT reboot.

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Step 7 — Convert VM to Template in Synology

In Synology VMM:

1. Select the VM

2. Click Action → Clone → Convert to Template

3. Name it:

RHEL9-GOLD-TEMPLATE

Done 🎉

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Step 8 — Create New Servers in 2 Minutes

From now on:

1. Create VM from template

2. Give it a new name

3. Start the VM

Each clone automatically generates:

• New machine ID

• New SSH keys

• Fresh identity

No installer. No boot hacks. No pain.

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Final Thoughts

Synology VMM is a fantastic home lab platform, but RHEL needs a few tweaks during installation. Once you create a golden template, spinning up new Linux servers becomes incredibly fast.

This setup is perfect for:

• DevOps labs

• Jenkins & Docker

• Databases

• IBM Sterling File Gateway

• Learning enterprise Linux

Happy lab building 🚀