Proxmox VM/Container Creator

Create Ubuntu 24.04 LXC containers or full VMs on Proxmox VE. Returns a Docker-ready host with SSH access.

When to Use

• "create proxmox vm"
• "create proxmox container"
• "spin up lxc"
• "new container on proxmox-host"
• Any time you need a fresh Linux host on Proxmox

This is a base skill. It creates the infrastructure. Other skills deploy applications onto it.

LXC vs VM Decision Guide

Default: LXC. Only use VM when the application explicitly needs kernel access.

User Inputs

Prerequisites Check

# SSH to Proxmox
ssh proxmox-host "pveversion" || echo "FAIL: Cannot SSH to Proxmox host"

# Check template (LXC)
ssh proxmox-host "pveam list local | grep ubuntu-24.04" || echo "Template not cached, will download"

# Find next CTID
ssh proxmox-host "pct list" | tail -n +2 | awk '{print $1}' | sort -n | tail -1
# Use max + 1

Execution Flow: LXC Container

Step 1: Ensure template is cached

ssh proxmox-host "pveam list local | grep ubuntu-24.04 || pveam download local ubuntu-24.04-standard_24.04-2_amd64.tar.zst"

Step 2: Find next available CTID

NEXT_CTID=$(ssh proxmox-host "cat <(pct list | tail -n +2 | awk '{print \$1}') <(qm list | tail -n +2 | awk '{print \$1}') 2>/dev/null | sort -n | tail -1")
NEXT_CTID=$((NEXT_CTID + 1))

Step 3: Create container

ssh proxmox-host "pct create $CTID local:vztmpl/ubuntu-24.04-standard_24.04-2_amd64.tar.zst \
  --hostname <name> \
  --memory <ram> \
  --cores <cores> \
  --rootfs local-lvm:<disk> \
  --net0 name=eth0,bridge=vmbr0,ip=dhcp \
  --unprivileged 1 \
  --features nesting=1 \
  --start 1"

Key flags:

• --unprivileged 1: Security best practice
• --features nesting=1: Required for Docker inside LXC
• --start 1: Start immediately after creation

Step 4: Wait for boot and get IP

sleep 10  # LXC boots in ~5 seconds

# Get IP from Proxmox
ssh proxmox-host "pct exec $CTID -- hostname -I"

# Or from DHCP
ssh proxmox-host "pct exec $CTID -- ip -4 addr show eth0 | grep inet | awk '{print \$2}' | cut -d/ -f1"

Step 5: Post-boot Docker setup

bash scripts/post-boot-setup.sh proxmox-host $CTID

Or manually:

ssh proxmox-host "pct exec $CTID -- bash -c '
  apt-get update -qq
  apt-get install -y -qq docker.io curl git htop
  systemctl enable docker && systemctl start docker
  mkdir -p /usr/local/lib/docker/cli-plugins
  curl -SL https://github.com/docker/compose/releases/latest/download/docker-compose-linux-x86_64 -o /usr/local/lib/docker/cli-plugins/docker-compose
  chmod +x /usr/local/lib/docker/cli-plugins/docker-compose
'"

Step 6: Verify

ssh proxmox-host "pct exec $CTID -- docker --version && pct exec $CTID -- docker compose version"

Execution Flow: Full VM

Use scripts/create-vm.sh for full VMs when LXC won't work:

ssh proxmox-host "qm create $VMID --name <name> --memory <ram> --cores <cores> \
  --net0 virtio,bridge=vmbr0 --scsihw virtio-scsi-pci \
  --scsi0 local-lvm:<disk>,format=raw --ide2 local-lvm:cloudinit \
  --boot c --bootdisk scsi0 --serial0 socket --vga serial0 \
  --ciuser deploy --cipassword <password> --ipconfig0 ip=dhcp \
  --start 1"

Return Values

Report to caller:

Container/VM Created: <name>
CTID/VMID: <id>
Type: lxc | vm
IP: <ip>
SSH: root@<ip> (LXC) or deploy@<ip> (VM)
Docker: installed
Docker Compose v2: installed

Teardown

# LXC
ssh proxmox-host "pct stop $CTID && pct destroy $CTID --purge"

# VM
ssh proxmox-host "qm stop $VMID && qm destroy $VMID --purge"

Critical Gotchas

See references/gotchas.md for full details:

1. Docker in LXC needs nesting=1: Without --features nesting=1, Docker fails to create networks
2. LXC limitations: No custom kernel modules, no raw sockets (AF_PACKET). Use VM for Security Onion, Zeek
3. Template caching: pveam download is slow first time. Check pveam list local first
4. CTID conflicts: Always check pct list before picking a CTID
5. Disk is thin-provisioned: 770GB free in pool but containers can fill up fast
6. Wazuh (CTID 105): 99.3% full at 25GB. Don't colocate storage-heavy services