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This article introduces the example analysis of Memcached high availability cluster, the content is very detailed, interested friends can refer to, hope to be helpful to you.

Characteristics of Memcached:

1. There is no limit to the amount of item data that can be saved in Memcached, as long as there is enough memory

The maximum memory used by a single process in 2.Memcached is 2GB. To use more memory, you can start multiple Memcached processes on different ports.

3.Memcached is a non-blocking socket communication service, based on libevent library, because of non-blocking communication, read and write to memory very fast

4.Memcached is divided into server and client. Multiple servers and clients can be configured. It is widely used in distributed services.

5.Memcached is very efficient as a small-scale data distributed platform.

Server IP address software package main Memcached192.168.5.129libevent-2.1.8-stable.tar.gz, memcached-1.5.9.tar.gz, magent-0.5.tar.gz, keepalived build Memcached server from Memcached192.168.5.139libevent-2.1.8-stable.tar.gz, memcached-1.5.9.tar.gz, magent-0.5.tar.gz, keepalivedClient192.168.5.141telnet

The Memcached server needs to be built on both servers in exactly the same way. When installing the memcached server, you need to install libevent first, and then install memcached.

Install the environment package

Yum-y install gcc gcc-c++ make

Compile and install libevent (must be installed first)

# decompression

Tar zxvf libevent-2.1.8-stable.tar.gz-C / opt

# change to the libevent directory

Cd / opt/libevent-2.1.8-stable/

# configuration

. / configure-- prefix=/usr/

# compilation and installation

Make & & make install

Compile and install memcached

# decompression

Tar zxvf memcached-1.5.9.tar.gz-C / opt/

# switch to memcached

Cd / opt/memcached-1.5.9/

# configuration (specify libevent path)

. / configure-- with-libevent=/usr/

# compilation and installation

Make & & make install

Optimized startup (Mencached that supports replication requires the installed libevent-2.1.so.6 module, otherwise the startup service will report an error)

Ln-s / usr/lib/libevent-2.1.so.6 / usr/lib64/libevent-2.1.so.6

Install magent on the primary server

Magent is a memcached proxy software, to prevent a single point of failure, the cache proxy can also backup, through the client connection cache proxy server, cache proxy server connection cache server.

# create a magent directory

Mkdir / opt/magent

# decompression

Tar zxvf magent-0.5.tar.gz-C / opt/magent

# switch to directory

Cd / opt/magent

# make dynamic link libraries shared by the system

/ sbin/ldconfig

# Edit ketama.h and add file header information

Vim ketama.h

# ifndef SSIZE_MAX#define SSIZE_MAX 32767#endif

# Editing Makefile

Vi Makefile

LIBS =-levent-lm

# compile (an executable file for manage will be generated after completion)

Make

# make the service easy for the system to identify

Cp / opt/magent/magent / usr/bin/scp / opt/magent/magent root@192.168.5.139:/usr/bin/ send to install keepalived from the server

# install keepalived from master server

Yum-y install keepalived

# modify the master-slave server configuration file

Vim / etc/keepalived/keepalived.conf

! Configuration File for keepalivedglobal_defs {notification_email {acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc} notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id MAGENT_H1 / / router_id customization But make sure that the master and slave are consistent} vrrp_script magent {script "/ root/shell/magent.sh" interval 2 / / defines a function, which has not been created yet To define} vrrp_instance VI_1 {state MASTER / / slave for BACKUP interface ens33 virtual_router_id 51 / / id is the same here priority 100 / / Master server priority is higher than slave server advert_int 1 authentication {auth_type PASS auth_pass 1111} track_script {magent / / Application Function} virtual_ipaddress {192.168.5.100 / / define vtp customization As long as the address is not in use} / / there are extra contents under the configuration file that can be deleted directly at this time.

# create a shell directory

Mkdir / root/shell

# create magent.sh script

Vim / root/shell/magent.sh

#! / bin/bashKeepalived= `ps-ef | grep keepalived | grep-v grep | wc-l`if [$Keepalived-gt 0]; then magent-u root-n 51200-l 192.168.5.100-p 12000-s 192.168.5.129 192.168.5.139:11211else pkill 11211-b 192.168.5.139:11211else pkill-9 magentfi

Parameter description:

-n 51200 # define the maximum number of user connections-l 192.168.5.100 # specify virtual IP-p 12000 # specify port number-s # specify master cache server-b # specify slave cache server

# Grant script execution permission

Chmod + x / root/shell/magent.sh

# start the keepalived service

Systemctl enable keepalived.service

Systemctl start keepalived.service

Operating on the slave server

# copy the keepalived configuration file on the master server

Scp root@192.168.5.129:/etc/keepalived/keepalived.conf / etc/keepalived/keepalived.conf

# Editing keepalived configuration file

Vim keepalived.conf

! Configuration File for keepalivedglobal_defs {notification_email {acassen@firewall.loc failover@firewall.loc sysadmin@firewall.loc} notification_email_from Alexandre.Cassen@firewall.loc smtp_server 192.168.200.1 smtp_connect_timeout 30 router_id magent_H2 # specify router_id} vrrp_script magent {# define function script "/ root/shell/magent.sh" Interval 2} vrrp_instance VI_1 {state BACKUP interface ens33 # Local Network Card name virtual_router_id 51 # id Master / Slave consistent priority 99 # Master Server priority is higher than Slave Server priority advert_int 1 authentication {auth_type PASS auth_pass 1111} virtual_ipaddress {# vip address 192.168.5.100} track_script {# call function magent}}

# create magent.sh script

Mkdir / root/shell

Vim / root/shell/magent.sh

#! / bin/bashKeepalived= `ip addr | grep 192.168.5.100 | grep-v grep | wc-l`if [$Keepalived-gt 0]; then magent-u root-n 51200-l 192.168.5.100-p 12000-s 192.168.5.129 grep 11211-b 192.168.5.139:11211else pkill-9 magentfi

# Grant script execution permission

Chmod + x / root/shell/magent.sh

# start the keepalived service

Systemctl enable keepalived.service

Systemctl start keepalived.service

Open memcached on the master and slave server

Memcached-m 512k-u root-d-l 192.168.5.129-p 11211 / / master server

Memcached-m 512k-u root-d-l 192.168.5.139-p 11211 / / slave server

Netstat-ntap | grep 11211

Client test connectivity

# install telnet client

Yum-y install telnet

# Connect to memcached

Telnet 192.168.175.188 12000

# Test the replication function

/ / Connect vip for testing, and insert user key value

[root@localhost ~] # telnet 192.168.5.100 12000Trying 192.168.5.100...Connected to 192.168.5.100.Escape character is'^] .set user 00 5test1STOREDget userVALUE user 0 5test1ENDquitConnection closed by foreign host.// connect to the main Memcached and query the user key value, which can be obtained successfully! [root@localhost ~] # telnet 192.168.5.129 11211Trying 192.168.5.129...Connected to 192.168.5.129.Escape character is'^] .get userVALUE user 0 5test1ENDquitConnection closed by foreign host.// connection from Memcached, query user key value, can also be obtained, successful! [root@centos7-1 ~] # telnet 192.168.5.139 11211Trying 192.168.96.17...Connected to 192.168.96.17.Escape character is'^] .get userVALUE user 0 5test1ENDquitConnection closed by foreign host. Test a single point of failure to shut down the primary server

View from the server

Client connection

This is the end of the sample analysis on the Memcached high availability cluster. I hope the above content can be helpful to you and learn more. If you think the article is good, you can share it for more people to see.

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