Video Walkthrough

Overview

This guide walks through setting up a fresh Ubuntu 24 VPS on DigitalOcean for Matrix Easy Mode.

The deployment flow includes:

1. Creating SSH keys
2. Creating a DigitalOcean droplet
3. Connecting to the server
4. Configuring firewall access
5. Installing Docker and Docker Compose
6. Verifying the environment is ready for Matrix Easy Mode

SSH Key Setup

Create SSH Key

Create a dedicated SSH key called do-key:

ssh-keygen -t ed25519 -f ~/.ssh/do-key

This creates:

~/.ssh/do-key

(private key — keep secret)

and:

~/.ssh/do-key.pub

(public key — safe to share)

View Public Key

Display the public key contents:

cat ~/.ssh/do-key.pub

Example:

ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAI... yourname@machine

Copy the ENTIRE line.

Add SSH Key To DigitalOcean

In DigitalOcean:

• Settings
• Security
• SSH Keys
• Add SSH Key

Paste the contents of:

~/.ssh/do-key.pub

Give it a friendly name:

do-key

Create The Ubuntu VPS

Create a new droplet using:

• Ubuntu 24
• your SSH key
• your preferred region and size

This guide assumes:

• Ubuntu 24
• root login via SSH key
• a public IPv4 address

Connect To The VPS

Since you created:

~/.ssh/do-key

explicitly specify it when connecting:

ssh -i ~/.ssh/do-key root@YOUR_SERVER_IP

Example:

ssh -i ~/.ssh/do-key root@203.0.113.10

First Connection Prompt

The first connection may show:

The authenticity of host '203.0.113.10' can't be established.
ED25519 key fingerprint is ...
Are you sure you want to continue connecting (yes/no/[fingerprint])?

Type:

yes

Successful Login

A successful login will look similar to:

root@ubuntu-s-2vcpu-2gb-lon1:~#

Common SSH Issues

Permission denied (publickey)

This usually means:

• wrong SSH key
• forgot -i
• wrong username
• public key not added to DigitalOcean
• droplet created without the SSH key attached

Optional: Create A Non-Root User

For day-to-day administration, you may want a non-root sudo user.

Example:

adduser nigel
usermod -aG sudo nigel

Copy SSH keys:

rsync --archive --chown=nigel:nigel ~/.ssh /home/nigel

Connect:

ssh -i ~/.ssh/do-key nigel@YOUR_SERVER_IP

Firewall Setup

Configure a minimal firewall using UFW.

ufw allow OpenSSH
ufw allow 80/tcp
ufw allow 81/tcp
ufw allow 443/tcp

ufw enable
ufw status

Ports

• 80/tcp = HTTP
• 443/tcp = HTTPS
• 81/tcp = Nginx Proxy Manager admin UI

Install Useful Utilities

apt update

apt install -y \
  curl \
  git \
  unzip \
  jq \
  htop \
  net-tools \
  dnsutils

Install Docker

Install Docker using the official Docker convenience installer:

curl -fsSL https://get.docker.com | sh

Allow Docker Without Root

usermod -aG docker $USER
newgrp docker

newgrp docker reloads the current shell so Docker group permissions apply immediately.

Alternative

Log out and SSH back into the server:

exit

Verify Docker

docker --version
docker compose version
docker run hello-world

Test Docker Compose

Create a test project:

mkdir ~/docker-test
cd ~/docker-test
nano compose.yml

Paste:

services:
  hello:
    image: hello-world

Run:

docker compose up

Next Step

Once Docker is installed and verified, continue with the main Matrix Easy Mode installation flow.

Recommended next steps:

• configure DNS
• install Nginx Proxy Manager
• create wildcard certificates
• deploy Matrix Easy Mode

Continue here:

• Installation Guide
• Architecture

Appendix: Manual Docker Installation

The repository-based Docker installation path is:

• more explicit
• more auditable
• useful for production-oriented environments

Install Required Packages

apt install -y ca-certificates curl gnupg

Create Docker Keyring Directory

install -m 0755 -d /etc/apt/keyrings

Add Docker GPG Key

curl -fsSL https://download.docker.com/linux/ubuntu/gpg | \
gpg --dearmor -o /etc/apt/keyrings/docker.gpg

Fix Permissions

chmod a+r /etc/apt/keyrings/docker.gpg

Add Docker Repository

IMPORTANT: Run as a single command.

echo "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.gpg] https://download.docker.com/linux/ubuntu $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | tee /etc/apt/sources.list.d/docker.list > /dev/null

Refresh Repositories

apt update

Install Docker Packages

apt install -y \
  docker-ce \
  docker-ce-cli \
  containerd.io \
  docker-buildx-plugin \
  docker-compose-plugin

Verify Installation

docker --version
docker compose version
docker run hello-world

SSH Key Cleanup

Delete the SSH key pair:

rm ~/.ssh/do-key ~/.ssh/do-key.pub

Verify deletion:

ls -la ~/.ssh | grep do-key

If nothing prints, the files are gone.

Safer Alternative

Rename instead of deleting:

mv ~/.ssh/do-key ~/.ssh/do-key.old
mv ~/.ssh/do-key.pub ~/.ssh/do-key.old.pub

Only remove keys if you are certain no existing servers still depend on them.