Shulou(Shulou.com)06/03 Report--

Load balancing

Upward and outward expansion of the server

Scale up (vertical scale): upgrade to a single node conditional hardware device or to a large node.

Scale out (scale out horizontally): add more nodes and distribute data and workloads among them.

The upward expansion is limited to its own physical hardware, which will have a bottle top.

Expanding outward can upgrade the service capacity indefinitely and expand the business capacity quickly.

Load balancing:

It is distributed to multiple operating units for execution to reduce the pressure on the system. Such as Web server, FTP server, enterprise critical application server and other key person server, etc., so as to complete the task together.

Advantages of load balancing:

Low cost, scalability, high reliability

Introduction and usage scenario of cloud load balancer Cloud load balancer is a traditional load balancer that provides users with load balancer instances in the form of services: configuration of cloud load balancer service monitoring rules on behalf of cloud load balancer activation and creation: cloud load balancer policy and forwarding rules customized by users. Backend CVM: it is a kind of CVM in the backend of load balancer service.

Ali Cloud load balancer service SLB is a service that distributes traffic to multiple servers. Load balancing can expand the external service capacity of the application system through distribution and improve the availability of the application system by eliminating a single point of failure.

Basic functions of cloud load balancing 1. Supports public or private network (used internally by Ali Cloud) type of load balancing service 2. Traffic distribution: currently provides layer 4 (TCP/UDP protocol) and layer 7 (HTTP/HTTPS protocol) load balancing service 3. Traffic scheduling: support weighted polling (WRR), weighted minimum number of connections (WLC) forwarding mode 4. Session persistence: during the life cycle of Session, the same client request can be forwarded to the same back-end ECS 5. 5. Health check: you can check the health of the backend ECS, automatically block the abnormal ECS, and automatically unblock the ECS when it returns to normal.

High availability of cloud load balancer

The best practice of load balancer SLB high availability configuration recommends that you take the following measures to improve the availability of load balancer business during the use and configuration of load balancer: 1. Deploy the cloud load balancer back-end servers in different availability zones in the same region, and then combine the characteristics of multiple availability zones of load balancer to achieve local disaster recovery. Access across availability zones increases access latency and needs to be assessed based on business sensitivity. two。 Enable the health check of the cloud load balancer backend ECS so that the cloud load balancer can automatically isolate or recover the abnormal ECS. 3. At least two or more ECS are configured at the cloud load balancer backend, so that the frontend access can be dispatched to other normal ECS when one of them is abnormal. Otherwise, the failure of a single ECS will result in the overall unavailability of the load balancer business. 4. Automatic reconnection mechanism at the business level, so that when the access request falls to the abnormal load balancer backend ECS, the client can customize the reconnection, so that the load balancer can schedule new requests to the normal ECS, thus improving business availability. Steps for creating and configuring a website load balancer SLB: planning and preparing data

Create and deploy a CVM ECS

Create and configure load balancer SLB

Resolve domain name

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