Why cluster chat server introduces load balancer

Load Balancer

At present, the project has only one server ,32 position Linux The system supports about 20000 user connections , To improve the concurrency of the server , Cluster or distributed deployment of servers is required .

The simpler way is to expand multiple servers horizontally , Each server runs independently ChatServer. Of course , The client cannot choose which server to connect to , The operation of this selection is left to Load Balancer , Also called reverse proxy device . Through the established algorithm , Distribute client requests to different servers .

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Nginx Configuration of

download Nginx After the installation package is decompressed , Enter this directory

Execute the command ：

This is a successful implementation , There may be a lack of PCRE Library or OpenSSL library , If it is missing, it will prompt , Follow the instructions to install .

Re execution make && make install, If there is an error , Enter the corresponding file according to the error , You can modify it. .
Two common mistakes can be seen here ：【Nginx make How to deal with errors in 】

After the download , Get into /usr/local/nginx Under the table of contents

Get into conf Catalog , find nginx.conf file

stay events and http Between , To configure Nginx TCP Load balancing

listen 8000, Refer to Nginx The port number that will listen . Let all clients connect 8000 port .

proxy_pass Myserver： All connections in 8000 Port requests , All go to Myserver Load balancing in the module . At this time, there are two servers and port numbers in this module .

weight=1, Means weight , So the process of polling . If the following weight = 2, Then suppose there are three client connections , The first server will be assigned a client , The second one is allocated two . In this case , If the hardware configuration of a server is high , You can make its weight bigger .

max_fail： heartbeat , If the heartbeat fails three times , By default, the server is down , Then when the client requests to enter , The server will not be loaded .