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Proxmox

Get started with Proxmox. Installation considerations, networking, disk encryption options, and migrating existing virtual machines.

Everything's presented in a useful order to follow if you're used to Hyper-V, VMware Workstation, or VirtualBox and want to jump in by moving to a Proxmox server.

What's most interesting about Proxmox is the Web UI gives you full console and GUI (yes, GUI desktop) access to your VM's through either noVNC or SPICE, even via a smart phone.

📚 Proxmox VE Documentation

⏬ Download

Verifying Signatures

The ISO URL points to an /iso/ folder on the Proxmox webiste. Browsing this manually reveals the following files:

You can use these along with the following public key to verify the ISO's integrity.

gpg --keyserver hkps://keyserver.ubuntu.com:443 --recv-keys 'F4E136C67CDCE41AE6DE6FC81140AF8F639E0C39'

# list keys
pub   rsa4096/0x1140AF8F639E0C39 2022-11-27 [SC] [expires: 2032-11-24]
    Key fingerprint = F4E1 36C6 7CDC E41A E6DE  6FC8 1140 AF8F 639E 0C39
uid                   [ unknown] Proxmox Bookworm Release Key <proxmox-release@proxmox.com>

💽 Install

Walk through the graphical or terminal installer. This is straight forward if you're used to installing hypervisor software.

Email

You'll need to choose an email address to send alerts to, this can be root@localhost or a real email.

🔑 Access

Proxmox listens on 22/tcp (SSH) and 8006/tcp (Web UI).

You can browse directly to your Proxmox machine's https://<IP>:8006 or use SSH. SSH allows you to do local port forwarding which will help you access the web interface from a jump host.

Jump Hosts

Tailscale

You can install Tailscale on proxmox, since it's Debian under the hood. This is a great way to isolate and access the management interface from authorized tailnet nodes.

From WSL to Jump Host

This example has a Yubikey connected to WSL on Windows:

  • The Yubikey is required to SSH into Proxmox
  • SSH Windows:8006 > WSL:8006
  • SSH WSL:8006 (with Yubikey) > JumpHost:SSH-PORT > Proxmox:8006
  • Now point your Windows browser to https://127.0.0.1:8006
  • It will forward to WSL which uses a jump host to forward again to proxmox's localhost:8006
# On Windows Host
$wsl_user = wsl.exe whoami
$wsl_ipv4 = wsl.exe ip addr show eth0 | sls "(?:(?:192\.168|172\.16|10\.(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?))\.)(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?\.)(?:25[0-4]|2[0-4][0-9]|[01]?[0-9][0-9]?)" | ForEach-Object { $_.Matches.Value }
PS> ssh -L 127.0.0.1:8006:127.0.0.1:8006 $wsl_user@$wsl_ipv4

# On WSL
JUMP_HOST_USER=''
JUMP_HOST_IP=''
JUMP_HOST_PORT=''
PROXMOX_USER=''
PROXMOX_IP=''
$ ssh -L 127.0.0.1:8006:127.0.0.1:8006 -J $JUMP_HOST_USER@$JUMP_HOST_IP:$JUMP_HOST_PORT $PROXMOX_USER@$PROXMOX_IP

⚙️ Configure

🔐 MFA

First, add 2FA/MFA to your root login. This can be a software token saved to your password manager or authenticator app, plus a hardware key using webauthn.

📦 Package Repositories

Next, if you have a valid enterprise subscription key, you're good to go. If not, disable the enterprise repos and enable the pve-no-subscription repo.

💻 System Updates

GUI: Click Updates then Refresh to run apt-get update; finally >_ Upgrade to run apt-get dist-upgrade

You can also run these from a bash shell on the Proxmox VE host.

🐚 SSH Authentication

root is allowed to login with a password by default. You can disable this in sshd_config once you've added your key to authorized_keys:

curl https://github.com/USERNAME.keys | tee -a /root/.ssh/authorized_keys
# symlink to /etc/pve/priv/authorized_keys

sed -i_bkup 's/^.*PasswordAuthentication.*$/PasswordAuthentication no/g' /etc/ssh/sshd_config
systemctl restart sshd

🔥 Firewall

The firewall is off by default. To enable it:

  • Datacenter > Firewall > Options > Click Firewall ... No to highlight it > Click Edit > Check Firewall
  • Now iptables -S will reveal a set of default rules

If you enable it, the only default allow rules are to 22/tcp and 8006/tcp from the local subnet.

You can define specific rules to the Proxmox VE host and VM guests from the GUI or using a text editor on:

  • /etc/pve/nodes/<nodename>/host.fw Host configuration

  • /etc/pve/firewall/<VMID>.fw VM / Container configuration

  • 🌐 Proxmox VE Firewall

🔎 Suricata

You can install suricata IPS on the Proxmox host. Keep in mind REJECTED or DROP'd packets do not go to suricata.

apt-get install suricata
modprobe nfnetlink_queue

⌨️ Users

To see all system users:

Datacenter > Permissions > Users

User details are defined on the filesystem under /etc/pve/user.cfg (note that passwords are under /etc/pve/priv/shadow.cfg).

💾 Disk Encryption

NOTE: A safer approach instead of full disk encryption is to install the Proxmox OS on an unencrypted disk, and use additional storage as encrypted disks for your production VM's. Proxmox does not offer full disk encryption by default. There are some issues you can encounter with this depending on your use case.

Mount an Encrypted Disk

You can easily mount and add an encrypted disk to an existing Proxmox server over SSH or from the Proxmox server console in the Web UI. As mentioned above, a perfect example is you've installed Proxmox itself on an unencrypted drive, and have other internal drives you can encrypt with LUKS or ZFS encryption that you want to store VM's on.

Creating a LUKS Partition

The easiest way to do this (and the way I initially set this up) is from an Ubuntu or Debian live OS. Using the disks application in Ubuntu, you can easily format and create a LUKS encrypted drive. Poweroff the Proxmox server, reboot into a live USB, create the drive, then continue.

Alternatively, you can do this all manually from the CLI within proxmox. NOTE: this will need tested and verified.

cryptsetup luksFormat /dev/sdXY
cryptsetup open --type luks /dev/sdXY <storage-id>
# Enter a passphrase, store it in your password manager

# Only create an ext4 filesystem if you need it, otherwise use lvm-thin for VM storage instead of ext4
mkfs.ext4 /dev/mapper/luks3-lvm

Now that we have a LUKS partition, we can mount it.

Get a sense of which partition(s) you'll want to add. In this case, the device is sdd and the partition is sdd1.

lsblk
<SNIP>
sdd                            8:48   0   1.8T  0 disk
└─sdd1                         8:49   0   1.8T  0 part

Unlock and mount the LUKS partition. You can make up any name for a storage ID, just stick to alphanumeric characters and hyphens -. Remember, you would only mkdir and mount a filesystem if you're using it as a filesystem. VM's benefit from lvm-thin data pools for more efficency than a filesystem.

Naming the Storage ID

If you look under Datacenter > Storage, you'll see the default ID's are local and local-lvm.

In this example, lets say you already have two other internal disks that are also LUKS encrypted.

Since this is the third disk, we'll call it luks3-lvm to stick to a similar naming convention.

# cryptsetup open --type luks /dev/sddX <storage-id>
cryptsetup open --type luks /dev/sdd1 luks3-lvm

# If this will be a filesystem and NOT an lvm-thin storage pool
mkdir /mnt/2tb-internal3
mount /dev/mapper/luks3-lvm /mnt/2tb-internal3

# To unmount the filesystem, and close the the LUKS partition if you need to
umount /mnt/2tb-internal3
cryptsetup close <storage-id>

To add the encrypted partition to the Proxmox data pool (basically so you see it in the GUI and can make use of it), you can use:

  • Datacenter > Storage > Add
  • ID: luks3-lvm (storage identifier created with cryptsetup)

New vgname and thinpool

Create a new volume group and thinpool for LUKS drives to share. This is because adding them to the existing volume group and thinpool means VM's and data will still be written to the unencrypted drives (if you aren't using full disk encryption).

Ai Usage

ChatGPT showed examples that led to posts and documentation detailing the following commands.

...or the CLI with pvesm:

# Helpful to visualize the pve storage
pvesm status

# Create a new volume group for LUKS drives
vgcreate luks-group /dev/mapper/luks3-lvm
WARNING: ext4 signature detected on /dev/mapper/luks3-lvm at offset 1080. Wipe it? [y/n]: y
  Wiping ext4 signature on /dev/mapper/luks3-lvm.
  Physical volume "/dev/mapper/luks3-lvm" successfully created.
  Volume group "luks-group" successfully created

# If you mess up, delete the group and remake it
vgremove luks-group

# Create a new thinpool for LUKS drives to share, leaving 5% of the drive for metadata
lvcreate --type thin-pool -l95%FREE -n <thinpool-name> <vgname>
lvcreate --type thin-pool -l95%FREE -n luks-data luks-group
  Thin pool volume with chunk size 1.00 MiB can address at most 254.00 TiB of data.
  WARNING: Pool zeroing and 1.00 MiB large chunk size slows down thin provisioning.
  WARNING: Consider disabling zeroing (-Zn) or using smaller chunk size (<512.00 KiB).
  Logical volume "luks-data" created.

# Add a LUKS thin-lvm data pool for VM storage
pvesm add lvmthin luks3-lvm --vgname pve --thinpool data --content images --content rootdir # lvm-thin is more efficient than a filesystem for VM storage

# Add a LUKS filesystem for backup, ISO, or other use
pvesm add dir luks3-lvm --path /mnt/2tb-internal3 --content backup # Only for backup, browsable filesystems

If you mess up and want to redo the pvesm, just use pvesm remove <storage-id>. Remember we came up with the storage ID when unlocking the LUKS partition during cryptsetup open --type luks /dev/sddX <storage-id>.

Backup LUKS Headers

Once everything's working it's recommended to backup the headers of your LUKS devices. These are ~2MB or larger binary blobs, the first "area" of the LUKS disk containing the encrypted key slots and necessary data to unlock the drive. Having a backup of these is easy to store as an attachment in a password vault, and can recover a drive if anything corrupts the header.

Ideally you have two encrypted drives that both have copies of the data, for example two LUKS drives, one for running the VMs, the other for saving backups of the VMs. It's less likely both will fail at the same time, even less so if the "backup" drive is an external device that isn't always connected.

cryptsetup luksHeaderBackup --header-backup-file <file> <device>
cryptsetup luksHeaderBackup --header-backup-file /root/sddX-luks3-lvm.bin /dev/sddX

Header Backup Storage

In most cases, it's fine to leave the header binary here in /root of the Proxmox unencrypted drive. An attacker would still need the key along with the header, and if the device itself is physically stolen, the LUKS volume itself also contains the header. This is a small trade off for having access to your header backup. Assume an attacker who could brute force your drive's key would already know how to extract the header, and has physical access.

That said, you may choose to save the header to your password manager and delete it from proxmox.

# Destroy the header file
shred -n 7 -v /root/sddX-luks3-lvm.bin

Before you're done you can do two more things; if you're using this partition as a filesystem type=dir, or you want to use a keyfile to unlock your drives on boot, set autodecryption and set auto-mounting.

Keyfile Storage

Typically what you'd do is use full disk encryption on the OS drive, requiring a password over SSH with dropbear_initramfs on remote startup. This will decrypt the boot drive. This is where you would be safe to store keyfiles. Do not store keyfiles on unencrypted partitions, as it would be easy to decrypt your drives with physical or shell access.

# Without a keyfile, simply map the drive but still require a passphrase
echo "luks3-lvm UUID=$(blkid -s UUID -o value /dev/sdd1 | tr -d '\n') none luks" | tee -a /etc/crypttab

# With a keyfile stored in the filesystem root, literally as /keyfile
echo "luks3-lvm UUID=$(blkid -s UUID -o value /dev/sdd1 | tr -d '\n') /keyfile luks" | tee -a /etc/crypttab

# Mount the volume as a filesystem under /mnt (we created this path eariler)
echo 'UUID=$(blkid -s UUID -o value /dev/sdd1 | tr -d '\n') /mnt/2tb-internal3    ext4    defaults 0   2" >> /etc/fstab

Unlocking the Drives

From here, anytime you update and reboot the Proxmox server, you'll just need to paste this command into the terminal through the WebUI and enter your passphrase to unlock the LUKS disk. Be sure to always use the same storage ID when mounting the LUKS partition, so pvesm can access it.

cryptsetup open --type luks /dev/sddX <storage-id>
cryptsetup open --type luks /dev/sddX luks3-lvm

That's it. It's already mapped to your pve storage manager, and remembered there.

Full Disk Encryption

One option is to install Debian with FDE, then install Proxmox on top of it. However it's recommended to just install Proxmox following one of the paths below.

  1. Install Proxmox with ZFS
  2. Reboot into recovery mode from the installer USB
  3. Follow these steps to enable ZFS encryption
  4. Follow these steps to install dropbear-initramfs for remote decryption over SSH
  5. Encrypt the dataset for VMs and containers (which is also step 5 in this post)

ZFS + Dropbear, all of the resources below came from this post: FDE with ZFS

LUKS + Dropbear

🔀 Migrating VMs

Hyper-V

Follow the link referenced above. Essentially, with no snapshots on the Hyper-V VM you wish to migrate (you can export the VM and import it back into Hyper-V so it's separate from your "main" copy, to delete the snapshots, then export it again) export your Hyper-V VM so you have the .vhdx file. Move it over to the Proxmox filesystem.

Filesystem Space and Migrating VMs

An external drive or larger filesystem space within Proxmox is useful here, as by default Proxmox gives its default "filesystem" on the OS drive roughly 100GB while leaving the remaining space to lvm-thin pool storage for VMs.

This is not explicitly talked about in the post, but if you cannot access the .vhdx file on your Hyper-V host by mounting a share on to the Hyper-V host on Proxmox, you should use an external drive to transfer the VM. With the average size likely being over 40GB, it will take a long time to scp, rsync, or similar.

Since the OS drive has roughly 100GB on the root filesystem, the majority of the remaining space is lvm-thin space, which is a special type of storage format efficient for VM's but lacking a filesystem.

Both an external drive and a fileshare allow you to import the VM directly to the lvm-thin space without accidentally overruning your /root filesystem's space which can happen if you copy the VM directly onto the OS drive filesystem before importing it.

Create the VM in Proxmox

Create the VM as you would if you were making it from scratch, following the steps in the linked forum post (q35 for the VM type, and then detach the default disk). Use the qm disk import <vmid> <source> <storage> [OPTIONS] command to import the .vhdx file as the disk image for your Hyper-V VM.

qm disk import 105 /mnt/wd500-external/Virtualization/Wazuh/Virtual\ Hard\ Disks/Wazuh.vhdx luks3-lvm
importing disk '/mnt/wd500-external/Virtualization/Wazuh/Virtual Hard Disks/Wazuh.vhdx' to VM 105 ...
  Logical volume "vm-105-disk-3" created.
transferred 0.0 B of 127.0 GiB (0.00%)
transferred 1.3 GiB of 127.0 GiB (1.00%)
transferred 2.5 GiB of 127.0 GiB (2.00%)
transferred 3.8 GiB of 127.0 GiB (3.00%)
transferred 5.1 GiB of 127.0 GiB (4.00%)
<SNIP>
transferred 125.9 GiB of 127.0 GiB (99.12%)
transferred 127.0 GiB of 127.0 GiB (100.00%)
transferred 127.0 GiB of 127.0 GiB (100.00%)
Successfully imported disk as 'unused1:luks3-lvm:vm-102-disk-3'

Add (attach) the disk under the VM's settings. Be sure to go into "Options", not "Hardware" and set this disk first in the boot order. In the event this is a Linux VM, even with SecureBoot enabled you'll be able to boot it, and get running.

That's really it, be sure to install the spice-vdagent service on the guest to leverage additional virtualization features if you want them, though this is not necessary.

Fix any issues (such as networking), poweroff, then take your first snapshot.

⚙️ VM Configuration

🛜 Virtual NIC

This is the equivalent of creating a virtual NIC (not to be confused with a VLAN) in VMware or VirtualBox for guest-to-guest communication (for example a LAN and OPT NIC to attach to a pfSense VM). First you need to create another Linux Bridge network device that isn't attached to any physical network ports.

  • Under Datacenter, select your proxmox-ve hostname > System > Network > Create
  • Name it, check [x] autostart, create
  • Now click "Apply Configuration" at the top, so your new vmbrX shows as "Active: Yes"

Now when creating the VM:

  • [VM Name] > Hardware > Add > Network Device
  • Add two, the WAN side can be the default vmbr0, the LAN side is your new vmbrX with either intel E1000 or virtIO
  • One will receive DHCP / access to the outside world over the Proxmox virtual brdige
  • The other will remain purely virtual (for example pfSense could then provide DHCP to that NIC)