OCI Load Balancer

Oracle Cloud Infrastructure (OCI) Load Balancer is a service that provides automated traffic distribution from one entry point to multiple servers in a backend set. It helps ensure that your applications are highly available and can handle large amounts of traffic by distributing the load among multiple instances.

Featureset:

Here's a summary of the feature set of Oracle Cloud Infrastructure (OCI) Load Balancer:

1. High Availability:

- Regional Load Balancer: Distributes traffic across multiple Availability Domains (ADs) within a region.

- Multi-AD Deployment: Ensures high availability by deploying instances across different ADs.

2. Scalability:

- Automatic Scaling: Adjusts dynamically based on traffic load.

- Support for Large Workloads: Handles millions of requests per second.

3. Traffic Management:

- Load Balancing Algorithms: Round-robin, least connections, IP hash.

- Session Persistence: Directs requests to the same backend server based on session cookie or IP hash.

- SSL Termination: Offloads SSL processing to the load balancer.

4. Security:

- Access Control Lists (ACLs): Traffic rules based on IP address ranges.

- Integration with WAF: Enhanced security against web attacks.

5. Health Checks:

- Proactive Monitoring: Only directs traffic to healthy backend servers.

- Customizable Health Checks: Supports HTTP, HTTPS, and TCP checks.

6. Global Reach:

- Global Load Balancing: Distributes traffic across multiple regions.

Types of Load Balancers

1. Public Load Balancer:

- Routes internet traffic to backend servers.

- Provides a public IP address as the entry point.

2. Private Load Balancer:

- Routes traffic within a Virtual Cloud Network (VCN).

- Suitable for internal applications.

Oracle Cloud Infrastructure (OCI) Load Balancer architecture is designed to provide high availability, scalability, and robust traffic management for applications. Here's an overview of the architecture:

Architecture Components:

1. Frontend (Client Traffic):

- Public Load Balancer: Accepts incoming traffic from the internet.

- Private Load Balancer: Accepts traffic from within the Virtual Cloud Network (VCN).

2. Load Balancer:

- Listeners: Listens for incoming client traffic on specified ports and protocols (HTTP, HTTPS, TCP).

- SSL Termination: Offloads SSL encryption/decryption from backend servers, improving performance.

- Access Control Lists (ACLs): Defines rules for allowing or denying traffic based on IP address ranges.

3. Backend Sets:

- Backend Servers: A group of instances (VMs or bare metal) that handle the client requests.

- Load Balancing Algorithms: Determines how traffic is distributed among backend servers (round-robin, least connections, IP hash).

- Health Checks: Monitors the health of backend servers and ensures only healthy servers receive traffic.

4. Routing Policies:

- Path-based Routing: Routes traffic based on URL paths.

- Host-based Routing: Routes traffic based on host headers.

5. Security:

- Integration with Web Application Firewall (WAF): Provides protection against web attacks.

- SSL Certificates: Ensures secure communication between clients and the load balancer.

6. Monitoring and Logging:

- Metrics: Provides real-time data on load balancer performance and traffic patterns.

- Logs: Captures detailed logs for troubleshooting and analysis.

High-Level Architecture:

1. Public Load Balancer Architecture:

- Frontend Interface: Exposes a public IP address for clients to connect.

- Listener: Configured to listen on specific ports (e.g., 80 for HTTP, 443 for HTTPS).

- SSL Termination: Optional, configured to handle SSL decryption.

- Backend Set: Contains multiple backend servers distributed across multiple Availability Domains (ADs).

- Health Checks: Regularly check the health of backend servers.

- Traffic Distribution: Uses specified algorithms to distribute client requests.

2. Private Load Balancer Architecture:

- Frontend Interface: Exposes a private IP address within the VCN.

- Listener: Similar to public but only accessible within the VCN.

- Backend Set: Backend servers are also within the VCN.

- Security: Additional security layers can be applied using VCN security lists and network security groups (NSGs).

3. High Availability and Scalability

- Regional Load Balancer: Distributes traffic across multiple ADs within a region for high availability.

- Automatic Scaling: Dynamically adjusts resources to handle varying traffic loads, ensuring optimal performance and availability.

- Disaster Recovery: Configurable for multi-region deployments to maintain service continuity in case of regional failures.

Detailed Workflow:

1. Client Request:

- A client sends a request to the load balancer's public or private IP address.

2. Listener Processing:

- The listener receives the request on the specified port and protocol.

- If configured, SSL termination decrypts the request.

3. Traffic Management:

- The load balancer evaluates routing policies (path-based or host-based) to determine the appropriate backend set.

- The selected load balancing algorithm distributes the request to one of the healthy backend servers.

Use Case: High Availability and Scalability for an E-commerce Website

Scenario

An e-commerce company wants to deploy its web application on Oracle Cloud Infrastructure. The application needs to handle high traffic volumes, ensure high availability, provide secure transactions, and maintain optimal performance during peak shopping seasons.

Solution Architecture

1. Public Load Balancer: To manage incoming internet traffic.

2. Private Load Balancer: To manage internal microservices communication.

3. Backend Servers: Multiple instances distributed across different Availability Domains (ADs) for redundancy.

4. SSL Termination: To offload SSL processing from backend servers.

5. Health Checks: To monitor the health of backend servers and route traffic only to healthy ones.

6. Web Application Firewall (WAF): To protect against common web attacks.

7. Routing Policies: To direct traffic based on URL paths (e.g., /checkout, /products).

Implementation Steps

1. Create VCN and Subnets:

- Set up a Virtual Cloud Network (VCN) with public and private subnets across multiple Availability Domains (ADs).

2. Provision Backend Servers:

- Deploy backend server instances in the public and private subnets across different ADs to ensure high availability.

3. Set Up Public Load Balancer:

- Create Public Load Balancer: Assign a public IP address for the load balancer.

- Configure Listeners: Set up listeners for HTTP (port 80) and HTTPS (port 443) protocols.

- Enable SSL Termination: Install SSL certificates on the load balancer.

4. Set Up Private Load Balancer:

- Create Private Load Balancer: Assign a private IP address within the VCN.

- Configure Listeners: Set up listeners for internal communication protocols.

5. Configure Backend Sets:

- Define Backend Servers: Add backend server instances to backend sets.

- Set Health Checks: Configure health checks (HTTP/HTTPS/TCP) to monitor server health.

6. Implement Routing Policies:

- Path-based Routing: Direct traffic based on URL paths (e.g., /checkout to Backend Set A, /products to Backend Set B).

7. Enhance Security:

- Web Application Firewall (WAF): Integrate WAF to protect against OWASP top 10 attacks.

- Access Control Lists (ACLs): Define ACLs to restrict access based on IP ranges.

8. Monitor and Scale:

- Enable Metrics and Logging: Monitor load balancer performance and traffic patterns.

- Auto Scaling: Configure auto-scaling policies to add/remove backend servers based on traffic load.