Load Balancer Listener Rules

Intelligent Traffic Steering with Listener Rules

Backpac’s Load Balancer Listener Rules provide a powerful and flexible way to route traffic intelligently based on various criteria. These rules enable customized routing logic, optimizing performance, scalability, and reliability for your application by directing traffic based on HTTP headers, RPC methods, source IPs, and forwarding preferences.

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What Are Load Balancer Listener Rules?

Listener Rules are configurations that define how traffic should be routed within Backpac’s Load Balancer. They examine the incoming requests based on various factors (e.g., method type, headers, or IP address) and determine the appropriate Target Group to forward the request to.

Each Listener Rule is associated with one or more Target Groups, which consist of a set of RPC endpoints. These groups are responsible for handling the actual requests.

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How Listener Rules Work

1. Request Matching

Listener Rules evaluate the incoming request based on the conditions specified:

• HTTP Headers: Match requests based on specific header values.
• RPC Methods: Route requests to different Target Groups based on the RPC method being called.
• Source IP: Identify and route traffic from specific IP addresses.

2. Rule Evaluation

When a request comes in, the Load Balancer evaluates the relevant Listener Rules:

• Priority-Based: Listener Rules are evaluated based on priority order (higher priority rules are checked first).
• Rule Matching: If a rule matches, the traffic is forwarded to the associated Target Group.

3. Traffic Forwarding

Once the correct Target Group is selected, the traffic is forwarded to one of the RPC endpoints in the group based on the balancing strategy (e.g., round-robin, latency, errors, rpc method support).

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Configuring Listener Rules in Backpac

Create a Listener Rule

1. Log in to your Backpac dashboard.
2. Navigate to the Load Balancer section.
3. Click Create Listener Rule.
4. Configure the following options:
   • Name: Give the Listener Rule a descriptive name (e.g., Ethereum-Method-Rule).
   • Priority: Assign a priority to the rule. Higher priority rules are evaluated first.
   • Conditions: Define the conditions under which this rule will apply:
     • RPC Methods: Specify which RPC methods trigger this rule.
     • HTTP Headers: Specify header values to match requests.
     • Source IPs: Define IP address ranges for source IP-based rules.
   • Target Group: Select the Target Group that the rule will route traffic to.
5. Save the rule.

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Example Use Case: Ethereum Method-Based Routing

Scenario

You have two RPC methods on the Ethereum network that need to be routed differently:

• eth_getBlockByNumber: Requires the highest block height (use Solana’s highest block height check).
• eth_getLogs: Can be routed to any available Ethereum endpoint.

Steps:

1. Create Listener Rules:
   • Rule 1: Matches requests for eth_getBlockByNumber and routes traffic to the Ethereum Target Group with the highest block height.
   • Rule 2: Matches requests for eth_getLogs and routes traffic to any available Ethereum Target Group.
2. Set Rule Priorities: Set Rule 1 to a higher priority than Rule 2.
3. Assign Listener Rule: Rule is attached to Blockchain Network it's created for.

Result:

• Requests for eth_getBlockByNumber are directed to the Ethereum Target Group with the highest block height.
• Requests for eth_getLogs are balanced across available Ethereum RPC endpoints.

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Listener Rule Features

Custom Routing Conditions

Listener Rules offer flexibility in traffic management with the following conditions:

• RPC Method Matching: Route traffic based on specific blockchain RPC methods.
• HTTP Header Matching: Route traffic based on custom headers or values, ideal for API versioning or authentication.
• Source IP Routing: Direct traffic from certain IP addresses to specific Target Groups for specialized handling.

Priority-Based Matching

• Rule Prioritization: Listener Rules are evaluated in a top-down manner based on the priority assigned during configuration.
• Precedence: Rules with higher priority are evaluated first, ensuring that specific routing conditions are honored.

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Benefits of Using Listener Rules

• Optimized Traffic Flow: Tailor routing decisions based on the most relevant criteria (e.g., method, header, IP).
• Scalability: Efficiently scale your RPC infrastructure by routing traffic to the most appropriate Target Group based on usage patterns.
• Customization: Set up fine-grained routing rules to meet specific application needs, like handling traffic spikes or managing API versioning.
• Reliability: Ensure that traffic is routed to the right endpoints, minimizing downtime and ensuring high availability.

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Conclusion

Backpac’s Load Balancer Listener Rules provide an advanced, flexible way to route traffic intelligently across RPC endpoints. By defining conditions based on headers, methods, and IP addresses, and assigning appropriate Target Groups, you can optimize performance, enhance scalability, and improve the reliability of your blockchain applications.