How to reduce VPC and Elastic load balancing costs?

To understand how to reduce costs for VPC and ELB, it's important to know the specific charges you are incurring:

VPC Cost Reduction

1. NAT Gateway Optimization:

   • NAT Gateways are charged per hour and for data processed. To reduce costs, consider using a single NAT Gateway for multiple private subnets or replacing NAT Gateways with NAT Instances where high availability is not critical.

2. VPC Endpoint Usage:

   • Use VPC Endpoints for AWS services to avoid data transfer charges associated with using the public internet. This is especially useful for services like Amazon S3 or DynamoDB.

3. Data Transfer Costs:

   • Minimize data transfer costs by keeping traffic within the same Availability Zone or using private IP addresses for communication within the same VPC.

Elastic Load Balancing Cost Reduction

1. Load Balancer Type:

   • Choose the right type of load balancer (Application Load Balancer, Network Load Balancer, or Classic Load Balancer) based on your needs. Application Load Balancers are generally more cost-effective for HTTP/HTTPS traffic.

2. Idle Load Balancers:

   • Delete unused or idle load balancers to avoid unnecessary charges.

3. Cross-Zone Load Balancing:

   • If you use an Application Load Balancer, consider disabling cross-zone load balancing if it's not needed, as it incurs additional charges.

4. Request-Based Pricing:

   • For Application Load Balancers, you are charged based on the number of new connections and the number of requests. Optimize your application to reduce unnecessary requests and connections.

5. Data Processing Charges:

   • Be mindful of the amount of data processed by the load balancer, as this can impact costs. Compressing data and using caching can help reduce data transfer costs.

6. Monitoring and Alerts:

   • Use AWS CloudWatch to monitor your load balancer's usage and set up alerts to notify you of any spikes in costs or usage.

General Tips

• Tagging and Monitoring: Use tags to categorize your AWS resources and monitor costs using AWS Cost Explorer. This can help identify areas where you can cut costs.
• Budgets: Set up AWS Budgets to receive alerts when your costs exceed predefined thresholds.
• Review and Optimize: Regularly review your VPC and ELB configurations and usage to identify opportunities for optimization and cost reduction.

Additionally, before implementing any services, it is advisable to estimate the costs using the AWS Price Calculator.

AWS ELB charges are based on the abstract concept of Load Balancer Unit (LCU), which is usually related to the usage of Connections, Bytes, and Rule evaluations. Therefore, if you want to reduce the charges caused by LCUs, you need to fundamentally reduce the values of these metrics.

For example: Use long-lived Keepalive connections on the client or server side to reduce the number of NewConnections. Or use HTTP compression techniques (gzip, br) to reduce the number of bytes processed by the ELB.

As a fully-managed product, AWS ELB itself is already a pay-as-you-go product, so there is no one-size-fits-all best practice for cost optimization. In reality, you still need to choose cost-saving strategies based on your actual billing scenarios and context.