Problems and solutions for deploying Nginx+KeepAlived cluster dual-active architecture in VMware
PrefaceUse nginx for load balancing. As the front end or middle layer of the architecture, with the increasing traffic, it is necessary to build a high-availability architecture for load balancing. Use keepalived to solve single point risks. Once nginx goes down, it can quickly switch to the backup server. Solutions to possible problems encountered in Vmware network configuration
InstallNode deployment
Web configurationweb1 starts the python http server vim index.html <html> <body> <h1>Web Svr 1</h1> </body> </html> nohup python -m SimpleHTTPServer 8080 > running.log 2>&1 & web2 starts a python http server vim index.html <html> <body> <h1>Web Svr 2</h1> </body> </html> nohup python -m SimpleHTTPServer 8080 > running.log 2>&1 & Turn off firewall firewall-cmd --state systemctl stop firewalld.service systemctl disable firewalld.service Now the browser access is normal, and the page shows Web Svr 1 and 2 Install Nginx on centos1 and 2First, configure the Alibaba Cloud source mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '/mirrors.aliyuncs.com/d' /etc/yum.repos.d/CentOS-Base.repo Install dependency packages yum -y install gcc yum install -y pcre pcre-devel yum install -y zlib zlib-devel yum install -y openssl openssl-devel Download nginx and unzip it wget http://nginx.org/download/nginx-1.8.0.tar.gz tar -zxvf nginx-1.8.0.tar.gz Install nginx cd nginx-1.8.0 ./configure --user=nobody --group=nobody --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_gzip_static_module --with-http_realip_module --with-http_sub_module --with-http_ssl_module make make install cd /usr/local/nginx/sbin/ # Check the configuration file ./nginx -t # Start nginx ./nginx Open nginx access firewall-cmd --zone=public --add-port=80/tcp --permanent systemctl restart firewalld.service At this time, you can see the homepage of nginx by visiting 130 and 131. Create nginx startup fileYou need to create the nginx startup file in the init.d folder. This way, each time the server restarts the init process, Nginx will be automatically started.
cd /etc/init.d/
vim nginx
#!/bin/sh
#
# nginx - this script starts and stops the nginx daemon
#
# chkconfig: -85 15
# description: Nginx is an HTTP(S) server, HTTP(S) reverse \
# Proxy and IMAP/POP3 proxy server
# processname: nginx
# config: /etc/nginx/nginx.conf
# pidfile: /var/run/nginx.pid
# user: nginx
# Source function library.
. /etc/rc.d/init.d/functions
# Source networking configuration.
. /etc/sysconfig/network
# Check that networking is up.
[ "$NETWORKING" = "no" ] && exit 0
nginx="/usr/local/nginx/sbin/nginx"
prog=$(basename $nginx)
NGINX_CONF_FILE="/usr/local/nginx/conf/nginx.conf"
lockfile=/var/run/nginx.lock
start() {
[ -x $nginx ] || exit 5
[ -f $NGINX_CONF_FILE ] || exit 6
echo -n $"Starting $prog: "
daemon $nginx -c $NGINX_CONF_FILE
retval=$?
echo
[ $retval -eq 0 ] && touch $lockfile
return $retval
}
stop() {
echo -n $"Stopping $prog: "
killproc $prog -QUIT
retval=$?
echo
[ $retval -eq 0 ] && rm -f $lockfile
return $retval
}
restart() {
configtest || return $?
stop
start
}
reload() {
configtest || return $?
echo -n $"Reloading $prog: "
killproc $nginx -HUP
RETVAL=$?
echo
}
force_reload() {
restart
}
configtest() {
$nginx -t -c $NGINX_CONF_FILE
}
rh_status() {
status $prog
}
rh_status_q() {
rh_status >/dev/null 2>&1
}
case "$1" in
start)
rh_status_q && exit 0
$1
;;
stop)
rh_status_q || exit 0
$1
;;
restart|configtest)
$1
;;
reload
rh_status_q || exit 7
$1
;;
force-reload
force_reload
;;
status)
rh_status
;;
condrestart|try-restart)
rh_status_q || exit 0
;;
*)
echo $"Usage: $0 {start|stop|status|restart|condrestart|try-restart|reload|force-reload|configtest}"
exit 2
esacVerify the configuration file and enter the following commands in sequence chkconfig --add nginx chkconfig --level 345 nginx on Add execute permissions to this file chmod +x nginx ls functions netconsole network nginx README Start Nginx service service nginx start service nginx status service nginx reload Nginx reverse proxy, load balancing (centos_1) Modify the nginx.conf configuration file and remove the commented code cd /usr/local/nginx/conf/ mv nginx.conf nginx.conf.bak egrep -v '^#' nginx.conf.bak egrep -v '^#|^[ ]*#' nginx.conf.bak egrep -v '^#|^[ ]*#|^$' nginx.conf.bak egrep -v '^#|^[ ]*#|^$' nginx.conf.bak >> nginx.conf cat nginx.conf The output is as follows
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
server {
listen 80;
server_name localhost;
location / {
root html;
index index.html index.htm;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
Reload nginx configuration # Test whether the configuration file is normal../sbin/nginx -t # Reload nginx configuration../sbin/nginx -s reload Configure nginx reverse proxy and load balancing
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
# websvr server cluster (also called load balancing pool)
upstream websvr {
server 192.168.211.128:8001 weight=1;
server 192.168.211.129:8001 weight=2;
}
server {
listen 80;
# Used to specify the IP address or domain name. Multiple configurations are separated by spaces. server_name 192.168.211.130;
location / {
# Submit all requests to the websvr cluster for processing proxy_pass http://websvr;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}Now restart nginx sbin/nginx -s reload The websvr names can be customized to indicate the meaning of these servers. In other words, you only need to add Now when you visit 130, Web Svr 1 and Web Svr 2 will switch on the page. The server will be selected based on the weight. The larger the weight value, the higher the weight. That is, if you refresh the page repeatedly, Web Svr 2 will appear twice on average and Web Svr 1 will appear once. So far, high availability cannot be achieved. Although web services can be done this way and single point failures can be handled in this way, if the nginx service fails, the entire system will basically be inaccessible, so multiple Nginx servers will be needed to ensure it. Multiple Nginx work together, Nginx high availability [dual machine master-slave mode] Add a new nginx service on the
worker_processes 1;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
sendfile on;
keepalive_timeout 65;
upstream websvr {
server 192.168.211.128:8001 weight=1;
server 192.168.211.129:8001 weight=2;
}
server {
listen 80;
server_name 192.168.211.131;
location / {
proxy_pass http://websvr;
}
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
}
}
# Reload nginx
sbin/nginx -s reloadNow visiting http://192.168.211.130/ can also get similar results as http://192.168.211.131/. The IPs of these two Nginx servers are different, so how can we make these two nginx servers work together? This requires the use of keepalived. Install the software and install two centos at the same time yum install keepalived pcre-devel -y Configure keepalived Backup on both cp /etc/keepalived/keepalived.conf keepalived.conf.bak
[root@localhost keepalived]# cat keepalived.conf
! Configuration File for keepalived
global_defs {
script_user root
enable_script_security
}
vrrp_script chk_nginx {
# Specify the monitoring script to detect whether the nginx service is running normally script "/etc/keepalived/chk_nginx.sh"
#Specify the monitoring time and execute interval 10 every 10 seconds
# The priority changes caused by the script result. If the detection fails (the script returns a non-zero value), the priority is -5.
# weight -5
# # A detection is considered a true failure only if it fails twice in a row. The priority will be reduced by weight (between 1-255)
# fall 2
# A successful detection is considered successful if it succeeds once. But does not change the priority# rise 1
}
vrrp_instance VI_1 {
#Specify the keepalived role, set the host to MASTER and the standby to BACKUP
state BACKUP
# Specify the interface of the HA monitoring network. CentOS7 uses ip addr to get interface ens33
# The virtual_router_id of the primary and backup routers must be the same. You can set it to the second group of IP addresses: must be between 1 & 255
virtual_router_id 51
# Priority value. In the same vrrp_instance, MASTRE must be higher than BAUCKUP. After MASTER recovers, BACKUP automatically takes over priority 90
# VRRP broadcast cycle in seconds. If the broadcast is not detected, it is considered that the service is down and the primary and backup advert_int 1
# Set the authentication type and password. The master and slave must have the same authentication {
# Set the vrrp authentication type, there are two main types: PASS and AH auth_type PASS
# The encrypted password must be the same on both servers for normal communication auth_pass 1111
}
track_script {
# Execute the monitored service, referencing the VRRP script, which is the name specified in the vrrp_script section. Run them periodically to change the priority chk_nginx
}
virtual_ipaddress {
# VRRP HA virtual address If there are multiple VIPs, continue to fill in 192.168.211.140
}
} Send the configuration file to node scp /etc/keepalived/keppalived.conf 192.168.211.131:/etc/keepalived/keepalived.conf For node state BACKUP priority 90 Main keepalived configuration monitoring script chk_nginx.sh Create a script to execute in keepalived
vi /etc/keepalived/chk_nginx.sh
#!/bin/bash
# Check whether there is an nginx process that assigns a value to the variable counter
counter=`ps -C nginx --no-header |wc -l`
# If there is no process, the value is 0
if [ $counter -eq 0 ];then
# Try to start nginx
echo "Keepalived Info: Try to start nginx" >> /var/log/messages
/etc/nginx/sbin/nginx
sleep 3
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
# Output system messages echo "Keepalived Info: Unable to start nginx" >> /var/log/messages
# If it has not started yet, end the keepalived process # killall keepalived
# Or stop /etc/init.d/keepalived stop
exit 1
else
echo "Keepalived Info: Nginx service has been restored" >> /var/log/messages
exit 0
fi
else
# Status is normal echo "Keepalived Info: Nginx detection is normal" >> /var/log/messages;
exit 0
fiNext, grant execution permissions and test chmod +x chk_nginx.sh ./chk_nginx.sh Restart keepalived on both sides systemctl restart keepalived systemctl status keepalived At this time, accessing tail -f /var/log/messages # If nginx turns off Keepalived Info: Try to start nginx Keepalived Info: Nginx service has been restored # nginx opens Keepalived normally Info: Nginx detection is normal When nginx detects normally, it will return 0; if there is no detection, it will return 1. However, keepalived does not seem to detect this return value to achieve the transfer, but to detect whether the keepalived service exists to release the local VIP and finally transfer the virtual IP to another server. References https://www.jianshu.com/p/7e8e61d34960 This is the end of this article about VMware deployment of Nginx+KeepAlived cluster dual-active architecture. For more related Nginx+KeepAlived cluster content, please search 123WORDPRESS.COM's previous articles or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future! You may also be interested in:
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