AWS 弹性负载均衡（ELB）和监控

Key Benefits of Cloud Computing: Elasticity and scalability help ensure application optimal performance by enabling horizontal scaling and handling increased work.
Elastic Load Balancer (ELB): It's crucial for AWS public cloud providers. Uses a multi-layer infrastructure to distribute user requests over computing resources, achieving elasticity and enabling autoscaling and monitoring.
Single-Machine vs. Tiered Architecture: Single-machine applications are prone to downtime. AWS' Elastic Load Balancer uses a three-tier architecture with user traffic distributed over EC2 instances in a separate VPC for high availability and seamless handling of increased demand.
Types of Load Balancers:
- Classic Load Balancer: Only for applications in EC2-Classic network, with limited control and scale. Likely to be phased out.
- Application Load Balancer (ALB): Distributes incoming requests based on HTTP headers using a round-robin algorithm. Serves distributed architectures best but not suitable for encrypted requests.
- Network Load Balancer (NLB): Newest and can handle high loads with low latency. Utilizes a flow-hash algorithm on the fourth layer and is useful for applications with fixed IP addresses.
ELB Monitoring and Logging:
- Gathering Data: ELB logs are sent to S3 every five minutes and contain various metrics. CloudWatch metrics and alarms, along with CloudTrail and VPC Flow Logs, are useful for monitoring.
- Leveraging Data: AWS doesn't guarantee log consistency. Logz.io's ELK Stack helps import, parse, and index logs for analysis, with Kibana providing dashboards for easy monitoring.
Summary: AWS load balancers route traffic and store data. The next step is to access, aggregate, and use this information for various purposes using the right tools.