What is the purpose of Docker?
Docker simplifies the deployment of backend servers by providing a consistent environment, managing dependencies, ensuring portability, facilitating persistent data management, and enhancing security and scalability.
Dependency Management: Docker enables you to encapsulate all dependencies required for your backend application within a container. This includes libraries, frameworks, and any other software packages needed to run the application. This ensures consistency across different environments and eliminates the “it works on my machine but its broken on yours” problem.
Portability: Docker containers are portable, meaning you can run them on any system that supports Docker without worrying about compatibility issues. This portability is essential for deploying backend servers across different environments, whether it’s on a developer’s local machine, a staging server, or a production server.
Persistent Data Management: Docker provides various mechanisms for managing persistent data within containers. This includes volume mounts, which allow you to map directories on the host system to directories within the container. This is crucial for storing data that needs to persist beyond the container’s lifespan, such as databases or user uploads.
Why do we use Nginx?
Nginx is used to serve web content, handle incoming requests, and route traffic to backend servers.
Web Server: Nginx serves as a web server, meaning it can handle HTTP requests from clients (such as web browsers) and respond with the appropriate content. It can serve static content directly or pass dynamic requests to backend application servers, such as those running Python, Node.js, or PHP.
Reverse Proxy: Nginx acts as a reverse proxy, sitting between clients and backend servers. When a client sends a request to access an application, Nginx receives the request and forwards it to the appropriate backend server. This enables load balancing, caching, and SSL termination, among other features.
Load Balancing: Nginx can distribute incoming requests across multiple backend servers to improve application performance and reliability. It can use various load-balancing algorithms to distribute traffic evenly, such as round-robin, least connections, or IP hash.
Caching: Nginx can cache static content or dynamic responses to reduce the load on backend servers and improve the overall performance of the application. Cached content can be served quickly to clients without needing to generate it again from the backend.
SSL Termination: Nginx can handle SSL/TLS encryption and decryption, allowing it to terminate SSL connections from clients and communicate with backend servers over unencrypted connections. This offloads the burden of SSL processing from backend servers and simplifies certificate management.
Security: Nginx provides various security features to protect applications from external attacks. This includes access control mechanisms, such as IP whitelisting or blacklisting, as well as rate limiting to prevent abuse or DDoS attacks. Additionally, Nginx can be configured to filter and block malicious requests, such as SQL injection attempts or cross-site scripting (XSS) attacks.
Logging and Monitoring: Nginx logs detailed information about incoming requests, responses, and server performance, which can be used for troubleshooting, auditing, and monitoring purposes. Integration with monitoring tools allows administrators to detect and respond to potential security threats or performance issues proactively.
Route 53 Purpose
DNS, including services provided by Route 53, plays a crucial role in how content is found on the internet by translating human-readable domain names into machine-readable IP addresses. It helps in the process of finding backend applications by mapping domain names to the IP addresses of the servers hosting those applications, facilitating communication between clients and servers on the internet.
Name Resolution: DNS acts as a distributed database that stores mappings between domain names and IP addresses. When a user wants to access a website or application by its domain name (e.g., www.example.com), their device first needs to resolve that domain name to an IP address. This process is known as name resolution.
DNS Hierarchy: DNS operates in a hierarchical structure, with different levels of DNS servers responsible for different parts of the domain name space. At the top of the hierarchy are the root DNS servers, followed by top-level domain (TLD) servers, authoritative DNS servers for specific domains, and finally, recursive DNS resolvers used by clients.
Query Process: When a user’s device needs to resolve a domain name, it sends a DNS query to a recursive DNS resolver, typically provided by their internet service provider (ISP) or configured manually. The resolver then recursively queries other DNS servers until it finds the authoritative DNS server responsible for the domain in question.
Route 53 Functionality: Route 53 provides DNS services that allow users to manage domain names and perform DNS resolution. Users can create hosted zones for their domains within Route 53 and configure DNS records such as A records (for IPv4 addresses), AAAA records (for IPv6 addresses), CNAME records (for aliases), and more.
Backend Application Discovery: DNS plays a crucial role in the process of finding backend applications on the internet. For example, suppose you have a backend application hosted on an AWS EC2 instance with a public IP address. By configuring a DNS A record in Route 53 to map a domain name (e.g., backend.example.com) to the IP address of the EC2 instance, clients can use the domain name to access the backend application.
Load Balancing and Failover: Route 53 also supports advanced DNS features such as traffic routing, load balancing, and failover. For example, you can use Route 53’s DNS-based load balancing to distribute incoming traffic across multiple backend servers, improving scalability and reliability.
What is Certbot?
When a user accesses a website secured with an SSL certificate managed by Certbot, the workflow involves encrypted communication between the client and server, facilitated by public-key and symmetric-key encryption techniques. Certbot automates the process of obtaining and renewing SSL certificates to ensure secure connections between clients and servers on the internet.
Client Request: The user’s web browser sends a request to access a website over HTTPS (Hypertext Transfer Protocol Secure). This request is encrypted using the Transport Layer Security (TLS) protocol, which relies on public-key cryptography.
Server Response: The web server hosting the website responds to the user’s request. If the website is secured with an SSL certificate, the server sends its public key along with the SSL certificate to the client.
Certificate Verification: The user’s web browser receives the SSL certificate from the server. It then verifies the authenticity and validity of the certificate. This involves checking the digital signature on the certificate using the public key of the certificate authority (CA) that issued the certificate. If the certificate is valid and trusted, the browser proceeds to establish a secure connection with the server.
Key Exchange: Once the certificate is verified, the client and server initiate a key exchange process to establish a shared secret key for symmetric encryption. This process typically involves Diffie-Hellman key exchange or Elliptic Curve Diffie-Hellman key exchange, both of which rely on public-key cryptography.
Session Encryption: With the shared secret key established, the client and server use symmetric encryption algorithms (such as AES or ChaCha20) to encrypt and decrypt data exchanged during the session. This provides confidentiality and integrity for the data transmitted between the client and server.
Data Transmission: Encrypted data is transmitted securely between the client and server over the HTTPS connection. This includes the HTML content of the web page, as well as any additional resources (such as images, scripts, or stylesheets) requested by the browser.
SSL Renewal with Certbot: Certbot is a tool used to automate the process of obtaining and renewing SSL certificates from trusted certificate authorities (such as Let’s Encrypt). When the SSL certificate managed by Certbot expires, Certbot automatically renews the certificate by generating a new certificate signing request (CSR), obtaining a new certificate from the CA, and updating the server configuration to use the new certificate.