Demo Deploying App

In this guide, you'll learn how to set up a production server on AWS to deploy your application. Later, this server will serve as the target when configuring your CI/CD pipeline. Follow these steps to launch an Amazon EC2 instance, configure SSH access, and set up a systemd service for your Flask app.

Step 1: Launching an EC2 Instance

When you log into the AWS console, you will see the EC2 management console displaying a list of running instances:

To create a new instance:

1. Click on the Launch Instance button.
2. Choose the desired Amazon Machine Image (AMI) and instance type. For a basic Linux server, the default configuration is sufficient.

Important Settings:

• Instance Type: Use the default instance type (usually a t2.micro with 1 GB memory and one vCPU).
• Key Pair: Select an existing SSH key (e.g., "main") for secure access. This will be crucial later when Jenkins connects to your server.
• Network Settings: Ensure you allow both HTTPS and HTTP traffic, as your server will host a web service.

After confirming your configuration, click Launch. Wait for a minute or two for the instance to start up.

Once the instance is running, return to the instances list to locate your production server and copy its IP address.

Step 2: Connecting to Your Server via SSH

Open your terminal and connect via SSH using your key (e.g., main.pem) and the default username ec2-user:

ssh -i main.pem ec2-user@<Your_EC2_Instance_IP>

Upon connecting, you might see a prompt similar to:

The authenticity of host '3.89.97.104 (3.89.97.104)' can't be established.
ED25519 key fingerprint is SHA256:MD1c0F1cn0pMsnd7TRAe1q3egJomo01RpuGpga4j3ARc.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes.
Warning: Permanently added '3.89.97.104' to the list of known hosts.
Amazon Linux 2023
https://aws.amazon.com/linux/amazon-linux-2023
[ec2-user@ip-172-31-16-211 ~]$

Step 3: Setting Up the Application Environment

Once connected, set up your application directory, create a Python virtual environment, and verify your working directory:

mkdir app
cd app
pwd  # Expected output: /home/ec2-user/app

Check that Python 3 is installed:

python3 --version

If needed, install or upgrade Python 3 before proceeding. Then, create a virtual environment:

python3 -m venv venv
ls  # You should see the "venv" directory.

Step 4: Configuring a systemd Service for the Flask App

Next, configure a systemd service so that your Flask application is automatically managed by the server. Create the service file in the /etc/systemd/system directory using sudo with your preferred editor (e.g., vi):

sudo vi /etc/systemd/system/flask-app.service

Paste the following configuration into the file:

[Unit]
Description=Flask Application Service
After=network.target

[Service]
User=ec2-user
Group=ec2-user
WorkingDirectory=/home/ec2-user/app/
Environment="PATH=/home/ec2-user/app/venv/bin"
ExecStart=/home/ec2-user/app/venv/bin/python3 /home/ec2-user/app/app.py

[Install]
WantedBy=multi-user.target

Ensure that the paths in WorkingDirectory, Environment, and ExecStart correctly reflect your server's configuration.

After saving the file, reload systemd to register your new service:

sudo systemctl daemon-reload

Enable the service to start automatically on boot:

sudo systemctl enable flask-app.service

You should see an output like:

Created symlink /etc/systemd/system/multi-user.target.wants/flask-app.service → /etc/systemd/system/flask-app.service.

Start the service:

sudo systemctl start flask-app.service

Check its status to ensure it is running:

sudo systemctl status flask-app.service

sudo systemctl restart flask-app.service

Next Steps

This guide completes the initial setup of your production server. In the next tutorial, you will learn how to configure your CI/CD pipeline so that every time you push code to Git, the updated code is automatically copied to your server and the service is restarted.

Happy deploying!