Lab 24: Build, Push, and Orchestrate NGINX with Docker Swarm¶

🧠 Objective¶

By the end of this lab, you will be able to:

Build a custom Docker image with NGINX and a custom homepage.
Push the image to Docker Hub.
Deploy and manage the image as a Swarm service on the Manager node.
Scale replicas up and down, and update the service with a new version.

🔧 Prerequisites¶

Docker Swarm initialized with 1 Manager and 2 Workers (from Lab 23).
A Docker Hub account.
Internet access from the Manager node.

🖥️ Step 1: Create a Project Folder on Manager Node¶

SSH into the Manager node (using PuTTY or Windows Terminal + SSH). Then run:

mkdir ~/nginx-lab
cd ~/nginx-lab

📝 Step 2: Create Custom `index.html`¶

Create a simple homepage file:

cat > index.html <<'EOF'
<!doctype html>
<html>
  <head><title>Lab 24 - NGINX v1</title></head>
  <body>
    <h1>Welcome to Lab 24!</h1>
    <p>This is Version 1 of our NGINX service running on Docker Swarm.</p>
  </body>
</html>
EOF

⚙️ Step 3: Create Dockerfile¶

cat > Dockerfile <<'EOF'
FROM nginx:stable-alpine
COPY index.html /usr/share/nginx/html/index.html
EXPOSE 80
EOF

🏗️ Step 4: Build Docker Image¶

Replace yourhubuser with your actual Docker Hub username:

docker build -t yourhubuser/lab24-nginx:v1 .

Verify the image:

docker images | grep lab24-nginx

🚀 Step 5: Push Image to Docker Hub¶

Login and push:

docker login
docker push yourhubuser/lab24-nginx:v1

Check on Docker Hub → you should see lab24-nginx repo with tag v1.

🌐 Step 6: Deploy Service on Docker Swarm¶

On Manager:

docker service create \
  --name lab24-service \
  --replicas 2 \
  --publish published=8080,target=80 \
  yourhubuser/lab24-nginx:v1

Check status:

docker service ls
docker service ps lab24-service

Test in browser:

http://<manager_public_ip>:8080

📈 Step 7: Scale Service¶

Scale up to 5 replicas:

docker service scale lab24-service=5

Check distribution:

docker service ps lab24-service

Scale down to 2 replicas:

docker service scale lab24-service=2

📝 Step 8: Update Homepage and Create v2 Image¶

Edit index.html:

cat > index.html <<'EOF'
<!doctype html>
<html>
  <head><title>Lab 24 - NGINX v2</title></head>
  <body>
    <h1>Welcome back to Lab 24!</h1>
    <p>This is Version 2, showing a rolling update in Docker Swarm.</p>
  </body>
</html>
EOF

Build & push new version:

docker build -t yourhubuser/lab24-nginx:v2 .
docker push yourhubuser/lab24-nginx:v2

🔄 Step 9: Rolling Update Service¶

Update service to new version:

docker service update --image yourhubuser/lab24-nginx:v2 lab24-service

Check update status:

docker service ps lab24-service

Refresh browser → you should now see Version 2 homepage.

🧹 Step 10: Cleanup¶

docker service rm lab24-service
docker image rm yourhubuser/lab24-nginx:v1 yourhubuser/lab24-nginx:v2

Terraform Clean up¶

IMPORTANT CLEAN UP AWS USING TERRAFORM

Complete the next lab to destroy all AWS resources to avoid cost on your credit cards

Troubleshooting tips¶

If you entered wrong yourhubuser during lab copy/paste then
- docker service ls You’ll see your service (e.g., lab24-service) with replicas 0/2 or stuck in Pending state.
- docker service rm lab24-service
- Verify: docker service ls

🔎 What You Learned¶

How to build Docker images directly on the Manager node.
How to push images to Docker Hub for use across the Swarm cluster.
How to orchestrate services with scaling and rolling updates.