站长资源服务器
Docker+keepalived+nginx实现主从热备的方法示例
前言
为解决单点故障,我们需要配置主从热备方案,服务器数量有限,故使用Docker模拟安装配置。
本次配置默认已经安装了Docker。
配置环境:centos7 64位
docker版本:Docker version 17.12.1-ce, build 7390fc6
1,拉取centos7镜像
docker pull centos:7
2,创建容器
docker run -it -d --name centos1 -d centos:7
3,进入容器centos1
docker exec -it centos1 bash
4,安装常用工具
yum updateyum install -y vimyum install -y wgetyum install -y gcc-c++ yum install -y pcre pcre-devel yum install -y zlib zlib-devel yum install -y openssl openssl--develyum install -y popt-develyum install -y initscripts yum install -y net-tools
5,将容器打包成新的镜像,以后直接以该镜像创建容器
docker commit -a 'cfh' -m 'centos with common tools' centos1 centos_base
6,删除之前创建的centos1 容器,重新以基础镜像创建容器,安装keepalived+nginx
docker rm -f centos1 #容器内需要使用systemctl服务,需要加上/usr/sbin/init docker run -it --name centos_temp -d --privileged centos_base /usr/sbin/init docker exec -it centos_temp bash 作者:江湖救急 链接:https://juejin.im/post/5dc517386fb9a04a9272110b 来源:掘金 著作权归作者所有。商业转载请联系作者获得授权,非商业转载请注明出处。
7,安装nginx
#使用yum安装nginx需要包括Nginx的库,安装Nginx的库 rpm -Uvh http://nginx.org/packages/centos/7/noarch/RPMS/nginx-release-centos-7-0.el7.ngx.noarch.rpm # 使用下面命令安装nginx yum install -y nginx #启动nginx systemctl start nginx.service #查看是否启动成功,出现nginx欢迎界面表示安装成功 curl 172.17.0.2
8,安装keepalived
1.下载keepalived wget http://www.keepalived.org/software/keepalived-1.2.18.tar.gz
2.解压安装:tar -zxvf keepalived-1.2.18.tar.gz -C /usr/local/
3.下载插件openssl yum install -y openssl openssl-devel
(需要安装一个软件包)
4.开始编译keepalivedcd /usr/local/keepalived-1.2.18/ && ./configure --prefix=/usr/local/keepalived
5.make一下 make && make install
9,将keepalived 安装成系统服务
mkdir /etc/keepalivedcp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/然后复制keepalived脚本文件:cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/ln -s /usr/local/sbin/keepalived /usr/sbin/可以设置开机启动:chkconfig keepalived on,到此我们安装完毕! #若启动报错,则执行下面命令 cd /usr/sbin/ rm -f keepalived cp /usr/local/keepalived/sbin/keepalived /usr/sbin/ #常用命令 systemctl daemon-reload 重新加载systemctl enable keepalived.service 设置开机自动启动systemctl disable keepalived.service 取消开机自动启动systemctl start keepalived.service 启动systemctl stop keepalived.service停止systemctl status keepalived.service 查看服务状态
10,修改/etc/keepalived/keepalived.conf文件
#备份配置文件 cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.backup rm -f keepalived.conf vim keepalived.conf #配置文件如下 vrrp_script chk_nginx { script "/etc/keepalived/nginx_check.sh" interval 2 weight -20 } vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 121 mcast_src_ip 172.17.0.6 priority 100 nopreempt advert_int 1 authentication { auth_type PASS auth_pass 1111 } track_script { chk_nginx } virtual_ipaddress { 172.17.0.100 } }
11,添加心跳检测文件
vim nginx_check.sh #以下是脚本内容 #!/bin/bash A=`ps -C nginx –no-header |wc -l` if [ $A -eq 0 ];then /usr/local/nginx/sbin/nginx sleep 2 if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then killall keepalived fi fi
12,给脚本赋予执行权限
chmod +x nginx_check.sh
13,设置开机启动
systemctl enable keepalived.service #开启keepalived systemctl start keepalived.service
14,检测虚拟IP是否成功,在宿主机里面执行下面命令,如果出现nginx欢迎界面表示成功
curl 172.17.0.100
15,将centos_temp 容器重新打包成镜像,然后利用这个新镜像再创建两个容器,实现热备效果
docker commit -a 'cfh' -m 'centos with keepalived nginx' centos_temp centos_kn
16,删除所有容器
docker rm -f `docker ps -a -q`
17,用centos_kn 镜像创建主服务器容器
docker run --privileged -tid --name centos_master --restart=always centos_kn /usr/sbin/init docker exec -it centos_master bash
18,修改centos_master里面nginx 欢迎页,
vim /usr/share/nginx/html/index.html
19,创建从服务器容器
docker run --privileged -tid --name centos_slave --restart=always centos_kn /usr/sbin/init docker exec -it centos_slave bash #修改keepalived.conf 配置文件,主要是state和priority两个参数的调整,其中master节点的priority值一定要比slave大才行 vrrp_script chk_nginx { script "/etc/keepalived/nginx_check.sh" interval 2 weight -20 } vrrp_instance VI_1 { state SLAVE interface eth0 virtual_router_id 121 mcast_src_ip 172.17.0.6 priority 80 nopreempt advert_int 1 authentication { auth_type PASS auth_pass 1111 } track_script { chk_nginx } virtual_ipaddress { 172.17.0.100 } }
20,修改完成之后重新加载
systemctl daemon-reload systemctl restart keepalived.service
21,修改nginx欢迎页(若nginx没启动则执行 systemctl start nginx.service)
vim /usr/share/nginx/html/index.html
22,测试
A> 分别在宿主机,centos_master,centos_slave中进行一下命令测试,如果显示都为Master的欢迎页面,说明配置成功1/3
curl 172.17.0.100
B> 此时停止centos_master容器( docker stop centos_master ),保留centos_slave容器,执行以下命令,若切换到Slave页面,则说明keepalived配置成功2/3
curl 172.17.0.100
C> 重启centos_master 容器,此时执行以下命令,看是从Slave切换到了Master,如果切换成功,说明我们配置到此成功了。
curl 172.17.0.100
说明,测试过程中,重启容器之后,nginx没有启动,需要进入容器启动一下,不然访问不到Master页面了,但是可以Ping通。
执行下面命令,配置nginx随机启动,这样不用每次重启容器还需要手动启动nginx
chkconfig nginx on
以上就是整个配置过程,希望对大家的学习有所帮助,也希望大家多多支持。