Intermediateproxmoxubuntucloud-initxrdpandroidkvmnested-virtualization

Dev Sandbox VM — Proxmox Ubuntu 24.04 with xrdp

Set up a Proxmox VM running Ubuntu 24.04 LTS cloud image with xrdp remote desktop, Android development tools, and nested virtualization. Fully automated via cloud-init with manual post-boot configuration for lightdm and Android SDK.

Step 1
Overview
This guide documents the complete setup of a development sandbox VM on Proxmox VE using Ubuntu 24.04 LTS cloud image. The VM provides a full desktop environment via xrdp, Android development tools, and nested virtualization for running VMs inside the VM.

Key Features:
- Remote desktop access via xrdp (port 3389)
- SSH access (port 22, key + password auth)
- XFCE4 desktop environment
- Android SDK and development tools
- Nested KVM virtualization
- Automated setup via cloud-init
VM Configuration:
- VM ID: 102
- Hostname: dev-sandbox
- IP: 192.168.1.xxx (assigned by DHCP; find yours via Proxmox Summary or router)
- OS: Ubuntu 24.04 LTS (cloud image)
- User: youruser
- Memory: 8192 MB
- Cores: 4
Step 2
Download Ubuntu Cloud Image
Download the Ubuntu 24.04 LTS cloud image to Proxmox local storage. This image is pre-configured for cloud-init and optimized for virtualization.
```
wget -O /var/lib/vz/template/iso/ubuntu-24.04-server-cloudimg-amd64.img \
  https://cloud-images.ubuntu.com/noble/current/noble-server-cloudimg-amd64.img
```

Step 3

Create Cloud-Init User Data File

Create the cloud-init user data YAML file that will configure the VM on first boot. This file contains all user setup, package installation, and initial configuration.

Store the file at /var/lib/vz/snippets/dev-sandbox-userdata.yaml on the Proxmox host.

#cloud-config
hostname: dev-sandbox
manage_etc_hosts: true
users:
  - name: sawyer
    groups: sudo, kvm, libvirt
    sudo: ALL=(ALL) NOPASSWD:ALL
    shell: /bin/bash
    lock_passwd: false
    passwd: "$5$YOURSALT$YOURHASH"  # Generate with: openssl passwd -5 'yourpassword'
    ssh_authorized_keys:
      - ssh-ed25519 AAAA... your-key-comment  # Replace with your public key from ~/.ssh/id_ed25519.pub
chpasswd:
  expire: false
ssh_pwauth: true
package_update: true
package_upgrade: true
packages:
  - xfce4
  - xfce4-goodies
  - xrdp
  - xorg
  - dbus-x11
  - openjdk-17-jdk
  - git
  - curl
  - wget
  - unzip
  - zip
  - adb
  - build-essential
  - qemu-kvm
  - libvirt-daemon-system
  - bridge-utils
  - cpu-checker
  - htop
  - neofetch
  - firefox
  - qemu-guest-agent
runcmd:
  - systemctl enable qemu-guest-agent
  - systemctl start qemu-guest-agent
  - echo xfce4-session > /home/sawyer/.xsession
  - chown sawyer:sawyer /home/sawyer/.xsession
  - systemctl enable xrdp
  - systemctl start xrdp
  - echo 'options kvm-intel nested=1' > /etc/modprobe.d/kvm-nested.conf
  - echo 'options kvm-amd nested=1' >> /etc/modprobe.d/kvm-nested.conf
final_message: "dev-sandbox is ready. Connect via xrdp on port 3389."

⚠ Heads up: When using `--cicustom user=` in Proxmox, it completely replaces the auto-generated cloud-init user config. Do NOT use `--ciuser`, `--cipassword`, or `--sshkeys` alongside it — they are silently ignored. All user setup (name, password, sudo, SSH keys, shell) must live inside the custom YAML.

Step 4

Create and Configure the VM

Run these commands on the Proxmox host as root to create the VM, import the cloud image disk, attach it, and configure cloud-init.

# Create VM
qm create 102 \
  --name dev-sandbox \
  --memory 8192 \
  --cores 4 \
  --net0 virtio,bridge=vmbr0,tag=2 \
  --ostype l26 \
  --machine q35 \
  --cpu host \
  --agent enabled=1

# Import cloud image as disk
qm importdisk 102 \
  /var/lib/vz/template/iso/ubuntu-24.04-server-cloudimg-amd64.img \
  local-lvm

# Attach disk and set boot order
qm set 102 \
  --scsihw virtio-scsi-pci \
  --scsi0 local-lvm:vm-102-disk-0 \
  --ide2 local-lvm:cloudinit \
  --boot order=scsi0 \
  --serial0 socket \
  --vga serial0

# Resize disk (30GB is sufficient; expand if needed)
qm resize 102 scsi0 +28G

# Attach the custom cloud-init user config
# NOTE: local:snippets maps to /var/lib/vz/snippets/
qm set 102 --cicustom "user=local:snippets/dev-sandbox-userdata.yaml"

# Start the VM
qm start 102

Step 5
Post-Boot: Fix lightdm Configuration
The cloud image ships with lightdm but no correct session/greeter defaults. Without this fix, xrdp logins fail with "Failed to start session".

SSH into the VM and create /etc/lightdm/lightdm.conf with the correct session and greeter settings.
```
# SSH into the VM
ssh sawyer@192.168.1.xxx

# Create lightdm configuration
sudo tee /etc/lightdm/lightdm.conf > /dev/null << 'EOF'
[Seat:*]
user-session=xfce
greeter-session=unity-greeter
EOF

# Restart lightdm
sudo systemctl restart lightdm
```
⚠ Heads up: The installed greeter is `unity-greeter`, not `lightdm-gtk-greeter`. Using the wrong greeter name causes the same "Failed to start session" error.
Step 6
Remote Desktop Access
Connect to the VM using any RDP client (Microsoft Remote Desktop, Remmina, etc.).

Connection Details:
- Host: 192.168.1.xxx
- Port: 3389
- Username: sawyer
- Password: (configured via the passwd hash in cloud-init)
You should see the XFCE4 desktop environment after logging in.
Step 7
SSH Access
SSH access is available from the Proxmox host or any machine with the SSH key configured in cloud-init.
```
ssh sawyer@192.168.1.xxx
```
⚠ Heads up: Password authentication is enabled (`ssh_pwauth: true`) as a fallback, but key-based authentication is recommended for security.

Step 8

Android Development Setup

After the VM is running, set up the Android SDK manually. The SDK is not included in cloud-init because it requires interactive license acceptance and the download size would slow first boot.

Download and install command-line tools:

# Download command-line tools
mkdir -p ~/android-sdk/cmdline-tools
cd /tmp
wget https://dl.google.com/android/repository/commandlinetools-linux-11076708_latest.zip
unzip commandlinetools-linux-11076708_latest.zip -d ~/android-sdk/cmdline-tools/
mv ~/android-sdk/cmdline-tools/cmdline-tools ~/android-sdk/cmdline-tools/latest

# Accept licenses and install build tools
export ANDROID_HOME=~/android-sdk
export PATH=$PATH:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools
yes | sdkmanager --licenses
sdkmanager "platforms;android-34" "build-tools;34.0.0" "platform-tools"

Step 9

Configure Android SDK Environment Variables

Add the Android SDK paths to your shell profile so they persist across sessions.

# Add to ~/.bashrc
cat >> ~/.bashrc << 'EOF'
export ANDROID_HOME=~/android-sdk
export PATH=$PATH:$ANDROID_HOME/cmdline-tools/latest/bin:$ANDROID_HOME/platform-tools
EOF

# Reload the configuration
source ~/.bashrc

Step 10

Configure Git Authentication

Set up Git with your user information and configure credential storage. This example uses a GitHub Personal Access Token (PAT) for authentication.

git config --global user.name "Your Name"
git config --global user.email "your@email.com"
git config --global credential.helper store

# On next git push/pull, enter PAT as password — it will be cached

Step 11

Verify Nested Virtualization

Nested virtualization was enabled via cloud-init in the kernel module configuration. Verify it's working:

# Check if nested virtualization is enabled
cat /sys/module/kvm_intel/parameters/nested
# Expected output: Y (for Intel) or N if not enabled

# Alternative check using kvm-ok
kvm-ok
# Expected output: KVM acceleration can be used

Step 12
Common Pitfalls and Solutions
Using --ciuser/--cipassword/--sshkeys with --cicustom user=
- Problem: User never created, SSH auth fails
- Solution: Put everything in the YAML; drop those flags
Wrong greeter in lightdm.conf
- Problem: "Failed to start session" on RDP
- Solution: Use unity-greeter not lightdm-gtk-greeter
Not including chpasswd: {expire: false}
- Problem: Password expired on first login
- Solution: Already included in the YAML above
Forgetting --cicustom uses local:snippets/ not a filesystem path
- Problem: qm set error
- Solution: Use local:snippets/filename.yaml format

Dev Sandbox VM — Proxmox Ubuntu 24.04 with xrdp

Overview

Download Ubuntu Cloud Image

Create Cloud-Init User Data File

Create and Configure the VM

Post-Boot: Fix lightdm Configuration

Remote Desktop Access

SSH Access

Android Development Setup

Configure Android SDK Environment Variables

Configure Git Authentication

Verify Nested Virtualization

Common Pitfalls and Solutions

Feature requests

Discussion