Shulou(Shulou.com)06/02 Report--

1. Load balancing

First of all, let's talk about what load balancing is. Load balancing is the most basic component of a high-availability architecture because load balancers can distribute many requests to different back-end servers to provide services to clients. Even if some of the machines cannot provide services for some reason, it will not affect the use of the whole system. Similarly, because requests are evenly distributed to different back-end servers, a single server does not have to bear too much load, and the client will have a better user experience.

2. Configure the instance

The tomcat at the back end runs the same application, but the ip is different. Basically, the three tomcat servers at the back end are regarded as one.

Just make sure that the front-end nginx proxy server can access the back-end tomcat server, even if it is not in the same network segment.

The default tomcat is running normally and can be accessed. Let's take a look at the configuration of nginx.

Configuration:

Http {

Upstream testproject {

Server 192.168.8.2:8080

Server 192.168.8.3:8080

Server 192.168.8.4:8080 backup

}

Server {

Listen 80

Server_name www.test.com/192.168.8.5

Location / {

Proxy_pass http://testproject;

}

}

}

The above is a very simple load balancer configuration, and there are not many other configurations. As long as it is configured like this, the load balancer is basically configured.

Explanation:

The field that upstream wants to configure in http.

Upstream streamname the whole streamname can be named whatever you want, and define it yourself.

To configure the server to be loaded in upstream, just fill in the address + port that can be accessed by the backend.

The status in the schedule can also be added to the backend of the proxy server.

Down

This server does not perform load balancing.

Backup

Enable this server when all machines participating in the load are unable to provide services

Max_fails

The number of times the request is allowed to fail

Fail_timeout

Time of service suspension after max_fails failure

Max_conns

Maximum number of connections

Configuration in server

Listen 80; listen on port 80

Server_name url/ip; if it is a private network, as long as it is configured with ip, if it is a public network, configure the domain name.

Proxy_pass is configured in location and followed by the name of the load balancer defined by http:// itself.

Actually, the configuration is very simple.

There are still many parameters for the configuration of load balancer. At present, only the most basic ones are explained here. After the configuration is completed, the architecture of load balancer has been built, but there are still many problems, such as session sharing, polling, and so on. There will be articles to explain them one by one.

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