Set up SSH Key Authentication

Continuing on my DevOps journey, I dove deeper into practical tasks that strengthened my skills in Linux server management, security, and automation. I set up SSH key authentication, secured Nginx with SSL/TLS, and implemented best practices for web server security. Exploring load balancing, I configured Nginx to distribute traffic for high availability. Documenting these steps keeps my journey purposeful and impactful.

Generate an SSH key pair on your local machine:

ssh-keygen -t rsa -b 4096 -C "[e-mail]"

Copy the public key to the remote server:

ssh-copy-id user@remote_server_ip

Test the connection:

ssh user@remote_server_ip

Confirm no password is requested.
Disable Password Authentication for SSH:

Open the SSH configuration file on the remote server:

sudo nano /etc/ssh/sshd_config

Modify or add the following lines:
yaml

PasswordAuthentication no
PubkeyAuthentication yes

Restart the SSH service:

sudo systemctl restart sshd

Web Server Security
Enhance Nginx Security with SSL/TLS:

Install Certbot and request a free SSL certificate:

sudo apt install certbot python3-certbot-nginx
sudo certbot --nginx -d yourdomain.com -d www.yourdomain.com

Verify SSL is working:

https://yourdomain.com

Implement Security Best Practices:

Update Nginx:

sudo apt update && sudo apt upgrade

Set up HTTP to HTTPS redirection:
nginx

server {
    listen 80;
    server_name yourdomain.com www.yourdomain.com;
    return 301 https://$host$request_uri;
}

Limit buffer size and request rate:
nginx

client_max_body_size 10M;
limit_req_zone $binary_remote_addr zone=mylimit:10m rate=5r/s;

Load Balancing
Basic Load-Balancing Concepts:

Distribute incoming traffic across multiple servers.
Ensure high availability and fault tolerance.
Set Up Nginx as a Simple Load Balancer:

Edit the Nginx configuration file:
nginx

upstream backend {
    server backend1.example.com;
    server backend2.example.com;
}
server {
    listen 80;
    server_name yourdomain.com;
    location / {
        proxy_pass http://backend;
    }
}

Test the configuration:

sudo nginx -t
sudo systemctl reload nginx