If you're a developer or coding enthusiast looking to create a lightweight development environment on Windows, setting up WSL, Docker, and Judge0 is a great option.
In this blog, I'll guide you step-by-step to install and configure everything smoothly.

🛠️ Step 1 : Install WSL and Ubuntu

First, we'll set up Windows Subsystem for Linux (WSL) and install Ubuntu as our Linux distribution.

1. Install WSL

Open PowerShell as Administrator and run:

wsl --install

This command installs WSL along with the latest version of Ubuntu automatically.

2. Restart Your Computer

Once WSL installation completes, you’ll be prompted to restart your computer.
Restart to apply the changes and complete WSL setup.

3. Complete Ubuntu Setup

After restarting, search for Ubuntu in the Start menu and open it.
It will ask you to create a UNIX username and password — just follow the prompts.

4. Update Ubuntu Packages

Keeping your packages updated is essential. Run:

sudo apt update && sudo apt upgrade -y

This updates your Ubuntu system and upgrades all existing packages silently (without asking confirmation).

5. (Optional) Adjust cgroup Settings better Docker compatibility

For better Docker compatibility, you can tweak your cgroup settings:

Open the GRUB configuration file:
```
 sudo nano /etc/default/grub
```
Find the line starting with GRUB_CMDLINE_LINUX and change it to:
```
 GRUB_CMDLINE_LINUX="systemd.unified_cgroup_hierarchy=0"
```
Save and exit (Ctrl + O → Enter → Ctrl + X).
Update GRUB and reboot:
```
 sudo update-grub
 sudo reboot
```

⚡ Note: If you don’t find the line inside GRUB, don't worry — just close the file (Ctrl + X) without making changes.

🐳 Step 2: Install Docker and Docker Compose

Now let’s install Docker and Docker Compose inside Ubuntu (WSL).

1. Install Docker

Run the following command:

sudo apt install -y docker.io

This installs Docker without asking for any confirmation.

2. Install Docker Compose

Then install Docker Compose:

sudo apt install -y docker-compose

Docker Compose helps you manage multi-container Docker applications easily.

⚙️ Step 3: Install and Set Up Judge0

Judge0 is an open-source API that can compile and run code in multiple languages — perfect for coding platforms or automated evaluation systems.

1. Download and Extract Judge0

. Download the latest release:

wget https://github.com/judge0/judge0/releases/download/v1.13.1/judge0-v1.13.1.zip

. Then unzip it:

unzip judge0-v1.13.1.zip

2. Set Up Secure Passwords

Navigate to the extracted folder:

cd judge0-v1.13.1

Open the configuration file:

nano judge0.conf

Generate strong random passwords (for Redis and Postgres) using this website:
🔗 Random.org Password Generator

Replace REDIS_PASSWORD and POSTGRES_PASSWORD values in judge0.conf with the generated passwords.
Save and exit (Ctrl + O → Enter → Ctrl + X).

3. Start Judge0 Services

Make sure you're inside the Judge0 folder:
```
  cd judge0-v1.13.1
```
Check if necessary files are present:

ls

If you see two main files/folders, it’s perfect.

4. Start the DB and Redis services:

Navigate to the Judge0 folder:
```
  cd judge0-v1.13.1
```
Start the database and Redis services:

sudo docker-compose up -d db redis

Wait a few seconds:

sleep 10s

Now start the remaining services:

docker-compose up -d

Wait a few more seconds:

sleep 5s

5. Verify the Installation

Open your browser and visit:

http://localhost:2358/docs

You should see the Judge0 API documentation page. 🎉
That means your Judge0 instance is running perfectly!

4. To stop the judge0

get running container ID's
```
 docker ps -a
```
- it will give some result like below

    root@root:~/leetlab/judge0-v1.13.1$ docker ps
    CONTAINER ID   IMAGE                  COMMAND                  CREATED          STATUS          PORTS                                       NAMES
    20f5666940cf   judge0/judge0:1.13.1   "/api/docker-entrypo…"   31 minutes ago   Up 30 minutes   2358/tcp                                    judge0-v1131_workers_1
    6564759cb244   judge0/judge0:1.13.1   "/api/docker-entrypo…"   31 minutes ago   Up 30 minutes   0.0.0.0:2358->2358/tcp, :::2358->2358/tcp   judge0-v1131_server_1
    085b059c5e77   postgres:16.2          "docker-entrypoint.s…"   48 minutes ago   Up 48 minutes   5432/tcp                                    judge0-v1131_db_1
    de2553f708ad   redis:7.2.4            "docker-entrypoint.s…"   48 minutes ago   Up 48 minutes   6379/tcp                                    judge0-v1131_redis_1

run stop cmd to stop the container

 docker stop 20f5666940cf 6564759cb244 085b059c5e77 de2553f708ad

To restart the jude0
- make sure you are correct directory
- Navigate to the Judge0 folder:
```
  cd judge0-v1.13.1
```

start the redis db

    docker-compose up -d db redis

start the judge0

    docker-compose up -d

Open your browser and visit:

    http://localhost:2358/docs

You should see the Judge0 API documentation page, meaning your Judge0 instance is running successfully!🎉

Setting Up WSL, Docker, and Judge0 on Windows (Complete Guide) 🖥️🚀

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