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My Proxmox cheatsheet

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My Proxmox cheatsheet

Set up Let’s Encrypt with Cloudflare

The HTTP-01 challenge didn’t work for me (port 80 was in use by Nginx Proxy Manager), so I used DNS-01 with Cloudflare as the DNS provider.

  1. Get the zone ID (from the Overview page of your domain in Cloudflare) and create an API token.
  2. Follow Let’s Encrypt with Cloudflare — 3os. This worked.
  3. Renewal is automatic via pve-daily-update.service (renews when the cert is within 30 days of expiry).

The official Proxmox certificate management docs are correct but less practical for this specific Cloudflare setup.

Setting up email notifications

Not yet working — revisit.

Updating Proxmox

# as root
apt update
apt dist-upgrade
apt autoremove
apt clean         # clears /var/cache/apt/archives

If updates fail with a disk-out-of-space error, it’s often /boot filling up with old kernels. I’ve fixed this by manually removing old kernels — apt autoremove should usually catch them, but doesn’t always.

For a more convenient updater (host + LXC + VMs in one go): BassT23/Proxmox.

Use xterm.js for VM terminal (nicer, allows copy/paste)

Proxmox uses noVNC by default, which doesn’t support copy/paste. Switching to xterm.js fixes this without installing anything in the VM. From Silicon’s blog.

On the host:

qm set <vmid> -serial0 socket   # e.g. qm set 100 -serial0 socket

In the VM: edit /etc/default/grub, change the line to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet console=tty0 console=ttyS0,115200"

Then:

sudo update-grub
sudo reboot                      # full reboot needed, not just restart of the VM

Now an xterm.js console option appears for that VM. If it looks frozen, press Enter a few times.

Sometimes this stops working — repeating the steps above usually fixes it. SPICE didn’t work on my corporate laptop.

pct — Proxmox container toolkit

For LXC containers. <id> below is the container ID (e.g. 100).

CommandPurpose
pct listList all containers
pct enter <id>Enter the container shell (like SSH)
pct status <id>Container status
pct start | stop | shutdown | destroy | unlock <id>Lifecycle
pct config <id>Show config
pct exec <id> -- <cmd>Run a command inside the container
pct snapshot <id> <name>Snapshot
pct restore <id> <file in /mnt/backup>Restore from backup
pct resize <id> rootfs +10GGrow rootfs (cannot shrink)
pct push <id> <local> <remote>Copy file in
pct pull <id> <remote> <local>Copy file out
pct create ...Create a new container

qm — QEMU/KVM machine management

For VMs. <id> below is the VM ID.

CommandPurpose
qm listList all VMs
qm status <id>VM status
qm start | stop | shutdown | reboot | destroy <id>Lifecycle
qm unlock <id>Unstick a stuck VM
qm config <id>Show config
qm set <id> <option> <value>Change config
qm resize <id> scsi0|virtio0|ide0 +20GGrow disk (cannot shrink)
qm snapshot <id> <name>Snapshot
qm rollback <id> <name>Roll back to snapshot
qm terminal <id>Serial console (needs serial set up — see xterm.js section above)
qm guest exec <id> -- <cmd>Run a command via QEMU guest agent
qm guest exec <id> -- su -c '<cmd>' <user>…as a specific user
qm create ...Create a new VM (still need to learn this properly)

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