LVS simple application

Prepare two virtual machines: Client / Server

• 环境：
  Distributor ID: CentOS
  Description: CentOS Linux release 7.7.1908 (Core)
  Release: 7.7.1908
  Codename: Core

LVS achieve load balancing

• Client as a client, Server as a server
• Server running at the end of the installation for scheduling LVS
• It provides a web service in Server-side run two mirrored nginx

Implementation

• Server installation docker
  visible official documents
  also see my other essay

• Start docker, mirrored pull nginx

systemctl start docker
docker pull nginx:1.17-alpine

• Deploy two vessels nginx as a web service: web1, web2

docker run --name web1 -d nginx:1.17-alpine
docker exec -it web1 /bin/sh
echo '<h1>web1<h1>' > /usr/share/nginx/html/index.html

docker run --name web2 -d nginx:1.17-alpine
docker exec -it web2 /bin/sh
echo '<h1>web2<h1>' > /usr/share/nginx/html/index.html

• Server-side view of the container and ip address of the
  Server side: run directly ifconfig
  container: The docker execoperation of the case into the containerifconfig

• Installation ipvsadm

yum -y install ipvsadm

• Add scheduling rules

ipvsadm -A -t Server端ip地址:80 -s rr
ipvsadm -a -t Server端ip地址:80 -r 容器ip地址:80 -m

• Client Client Access Server

curl Server端ip地址

Experimental results

Encounter problems

• Client-Server can not access the service side of the web, but can ping
  
• Server-side port 80 open Solution:

iptables -I INPUT -p tcp --dport 80 -j ACCEPT