Memcache配置手册

[root@node1 ~]# yum install memcached -y
[root@node1 ~]# vim /etc/sysconfig/memcached
# 设定监听端口
PORT="11211"
# 设定进程的属主
USER="memcached"
# 设定最大连接数
MAXCONN="1024"
# 设定最大缓存M数
CACHESIZE="64"
# 设定监听的IP
OPTIONS="-l 0.0.0.0"

[root@node1 ~]# systemctl enable --now memcached

[root@node1 ~]# firewall-cmd --add-port=11211/tcp --permanent
success
[root@node1 ~]# firewall-cmd --reload
success

[root@node1 ~]# yum install telnet -y

[root@node1 ~]# telnet localhost 11211
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
stats     # 显示Memcache状态
STAT pid 28849
STAT uptime 202
STAT time 1580478019
STAT version 1.5.6
STAT libevent 2.0.21-stable
STAT pointer_size 64
STAT rusage_user 0.025928
......
......

设定键、值保存在内存中
语法:设置[键][标志][有效期（秒）][数据大小（字节）]
标志：0=关闭压缩，1=打开压缩
有效期=0表示不确定
输入上述命令后，输入一个键的值
set test_key 0 0 10
test_value
STORED

get test_key
VALUE test_key 0 10
test_value
END

replace test_key 0 0 11     # 改变test_key的值
test_value2
STORED

get test_key
VALUE test_key 0 11
test_value2
END

append test_key 0 0 5     # 追加的值
,test
STORED

get test_key
VALUE test_key 0 16
test_value2,test
END

prepend test_key 0 0 6     # 预置值
test1,
STORED

get test_key
VALUE test_key 0 22
test1,test_value2,test
END

delete test_key     # 删除key
DELETED

# 对指定key增量其值
set mycounter 0 0 1
1
STORED

incr mycounter 1
2
get mycounter
VALUE mycounter 0 1
2
END

# 对指定key递减其值
decr mycounter 1
1
get mycounter
VALUE mycounter 0 1
1
END

flush_all      # 删除内存中所有缓存的数据
OK

# CAS (Check And Set)操作
# 使用CAS命令,更新数据.CAS ID为12
        cas语法格式:cas [键] [标记] [有效期(sec)] [数据大小(byte)] [CAS ID]
gets test_key
VALUE test_key 0 10 12
test_value
END

cas test_key 0 0 11 12
test2_value
STORED

gets test_key
VALUE test_key 0 11 13
test2_value
END

quit     # 退出Telnet

1) 安装Python Memcached客户端
[root@node1 ~]# yum install python-memcached -y

2) 测试
[root@node1 ~]# vim use-memcached.py
#!/usr/bin/env python

import memcache

client = memcache.Client(["127.0.0.1:11211"], cache_cas=True)

#  设置并获取一个Key
client.set("key01", "value01")
print "key01.value :", client.get("key01")

#  追加并确认 Key
client.append("key01", ",value02")
print "key01.value :", client.get("key01")

client.set("key02", 1)

#  增量
client.incr("key02", 100)
print "key02.value :", client.get("key02")

#  递减
client.decr("key02", 51)
print "key02.value :", client.get("key02")

#  CAS操作
client.set("key03", "value03")
print "key03.value :", client.gets("key03")
print "key03.casid :", client.cas_ids["key03"]
client.cas("key03", "value04")
print "key03.value :", client.gets("key03")

[root@node1 ~]# python use-memcached.py
key01.value : value01
key01.value : value01,value02
key02.value : 101
key02.value : 50
key03.value : value03
key03.casid : 26
key03.value : value04

1) 安装Python Memcached客户端
[root@node1 ~]# yum --enablerepo=epel install php-pecl-memcached -y

2) 测试
[root@node1 ~]# vim use-memcached.php
<?php
$memcache = new Memcached();
$memcache->addServer('localhost', 11211);
$memcache->setOption(Memcached::OPT_COMPRESSION, false);
#  设置并获取一个Key
$memcache->set('key01', 'value01');
print 'key01.value : ' . $memcache->get('key01') . "\n";

#  追加并确认 Key
$memcache->append('key01', ',value02');
print 'key01.value : ' . $memcache->get('key01') . "\n";

$memcache->set('key02', 1);
print 'key02.value : ' . $memcache->get('key02') . "\n";

#  增量
$memcache->increment('key02', 100);
print 'key02.value : ' . $memcache->get('key02') . "\n";

#  递减
$memcache->decrement('key02', 51);
print 'key02.value : ' . $memcache->get('key02') . "\n";

$memcache->set('key03', 'value03');
print 'key03.value : ' . $memcache->get('key03') . "\n";

#  CAS操作
$memcache->get('key03', null, $cas);
$memcache->replace('key03', 'value04');
if ($memcache->getResultCode() == Memcached::RES_NOTFOUND) {
    $memcache->add('key03', 'value03');
} else {
    $memcache->cas($cas, 'key03', 'value05');
}
print 'key03.value : ' . $memcache->get('key03') . "\n";
?>

[root@node1 ~]# php use-memcached.php
key01.value : value01
key01.value : value01,value02
key02.value : 1
key02.value : 101
key02.value : 50
key03.value : value03
key03.value : value04

1) magent说明
Magent是一款开源的Memcached代理服务器软件，采用 Magent 缓存代理，防止单点现象，缓存代理也可以做备份，通过客户端连接到缓存代理服务器，缓存代理服务器连接缓存服务器，缓存代理服务器可以连接多台Memcached机器；

2) 前期准备
1. 至少2台Memcached服务存在，并处于star状态。本示例为srv3及srv4两台服务器开启memcached服务

2. 拓扑:
                      +----------+
                      |  magent  |
                      +-----+----+
                        eth0|192.168.10.11/24
                            |
+------------+              |            +------------+
|  Backend1  |192.168.10.13|192.168.10.14|  Backend2  |
|  memcached +-------------+-------------+  memcached |
|    srv3    |                           |    srv4    |
+------------+eth0                   eth0+------------+
3) 下载magent
[root@srv1 ~]# mkdir -v magent
[root@srv1 ~]# cd -v magent
[root@srv1 magent]# wget \
https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/memagent/magent-0.6.tar.gz

4) 编译并安装magent
[root@srv1 magent]# tar xvfz magent-0.6.tar.gz
[root@srv1 magent]# yum install gcc libevent-devel -y
[root@srv1 magent]# make
#  错误1: 如果出现以下错误
magent.c: In function ‘writev_list’:
magent.c:729:17: error: ‘SSIZE_MAX’ undeclared (first use in this function)
    if (toSend > SSIZE_MAX ||
                 ^
magent.c:729:17: note: each undeclared identifier is reported only once for each function it appears in
make: *** [magent.o] Error 1

#  解决办法
[root@srv1 magent]# vim ketama.h
#   在头部加入以下代码
#ifndef SSIZE_MAX
#define SSIZE_MAX      32767
#endif

#  错误2: 如果出现以下错误
gcc: error: /usr/lib64/libevent.a: No such file or directory
gcc: error: /usr/lib64/libm.a: No such file or directory
make: *** [magent] Error 1

#  解决办法
[root@srv1 magent]# ln -s /usr/lib64/libm.so /usr/lib64/libm.a
[root@srv1 magent]# ln -s /usr/lib64/libevent.so /usr/lib64/libevent.a

#  编译成功后，复制已经编译好的magent命令
[root@srv1 magent]# cp magent /usr/bin/

[root@srv1 magent]# scp magent root@srv3.1000y.cloud:/usr/bin/
[root@srv1 magent]# scp magent root@srv4.1000y.cloud:/usr/bin/

[root@srv1 magent]# cd
[root@srv1 ~]# 

5) 启动magent
#   magent命令参数说明
-u: 指定运行用户
-n: 最大的连接数，默认为4096
-l: 小写L，magent监听的ip地址
-p: magent监听的端口
-s: 设置memcached主缓存的ip地址和端口
-b: 设置memcached备缓存的ip地址和端口

[root@srv1 ~]# magent -u root -n 51200 -l 192.168.10.11 -p 12000 -s 192.168.10.13:11211 -b 192.168.10.14:11211

6) 测试magent
[root@srv1 ~]# yum install telnet -y

[root@srv1 ~]# telnet 192.168.10.11 12000
Trying 192.168.10.11...
Connected to 192.168.10.11.
Escape character is '^]'.

set test_key 0 0 10
test_value
STORED

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.

7) 测试memcached两个节点是否存在test_key
(1) srv3节点测试操作
[root@srv3 ~]# yum install telnet -y
[root@srv3 ~]# telnet localhost 11211
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.

(2) srv4节点测试操作
[root@srv4 ~]# yum install telnet -y
[root@srv4 ~]# telnet localhost 11211
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.

8) 关闭srv3的memcached服务,并测试magent节点可以继续读取到test_key
[root@srv3 ~]# systemctl stop memcached

[root@srv1 ~]# telnet 192.168.10.11 12000
Trying 192.168.10.11...
Connected to 192.168.10.11.
Escape character is '^]'.

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.

#   当再次开启srv3的memcached时，如果出现取不到前面设置的所有值，因为重启以后，主节点数据全部清空，虽然备份节点有数据，但是主节点在备份节点不会生效。即主节点无法同步备份节点的数据

1) 拓扑
                      +----------+
                      |  client  |
                      +-----+----+
                        eth1|192.168.10.15/24
                            |
       |-----------VIP:192.168.10.250 ------------|
+------+------+             |             +-------+-----+
| Keepalived1 |192.168.10.11|192.168.10.12| KeepAlived2 |
|    magent   +-------------+-------------+    magent   |
|     srv1    |             |             |     srv2    |
+-------------+eth0         |         eth0+-------------+
                            |
+------------+              |            +------------+
|  Backend1  |192.168.10.13|192.168.10.14|  Backend2  |
|  memcached +-------------+-------------+  memcached |
|    srv3    |                           |    srv4    |
+------------+eth0                   eth0+------------+

2) 前提条件
1. 两个节点[srv1/srv2]均安装magent及keepalived
2. 两个节点[srv3/srv4]均安装memcached

3) 为srv2安装magent
[root@srv1 ~]# scp /usr/bin/magent root@192.168.10.12:/usr/bin/magent

4) 为srv1及srv2安装keepalived
[root@srv1 ~]# yum install keepalived procps-ng -y
[root@srv2 ~]# yum install keepalived procps-ng -y

5) 配置srv1的keepalived
[root@srv1 ~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

[root@srv1 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id srv1.1000y.cloud
}

vrrp_instance VI_1 {
    state MASTER
    interface eth0
    virtual_router_id 50
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.250
    }
	#   设定当前节点为Master时，所执行的脚本
    notify_master "/usr/bin/magent-start.sh"
    #   设定当前节点为Backup时，所执行的脚本
    notify_backup "/usr/bin/magent-stop.sh"
    #   设定当前节点为失败时，所执行的脚本
    notify_fault "/usr/bin/magent-stop.sh"
    #   如果无论什么状态都想执行指定脚本可按以下方式操作
    # notify "$PATH/xxx.sh"
}

[root@srv1 ~]# vim /usr/bin/magent-start.sh
#! /bin/bash
magent -u root -n 51200 -l 192.168.10.222 -p 12000 -s 192.168.10.13:11211 -b 192.168.10.14:11211

[root@srv1 ~]# vim /usr/bin/magent-stop.sh
#! /bin/bash
pkill magent

[root@srv2 ~]# chmod 755 /usr/bin/magent-start.sh
[root@srv2 ~]# chmod 755 /usr/bin/magent-stop.sh

[root@srv1 ~]# systemctl enable --now keepalived

6) 配置srv2的keepalived
[root@srv2 ~]# mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

[root@srv2 ~]# vim /etc/keepalived/keepalived.conf
global_defs {
   router_id srv2.1000y.cloud
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 50
    priority 50
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.10.250
    }
	# 设定当前节点为Master时，所执行的脚本
    notify_master "/usr/bin/magent-start.sh"
    # 设定当前节点为Backup时，所执行的脚本
    notify_backup "/usr/bin/magent-stop.sh"
    # 设定当前节点为失败时，所执行的脚本
    notify_fault "/usr/bin/magent-stop.sh"
}

[root@srv2 ~]# vim /usr/bin/magent-start.sh
#! /bin/bash
magent -u root -n 51200 -l 192.168.10.222 -p 12000 -s 192.168.10.13:11211 -b 192.168.10.14:11211

[root@srv2 ~]# vim /usr/bin/magent-stop.sh
#! /bin/bash
pkill magent

[root@srv2 ~]# chmod 755 /usr/bin/magent-start.sh
[root@srv2 ~]# chmod 755 /usr/bin/magent-stop.sh

[root@srv2 ~]# systemctl enable --now keepalived

7) 测试keepalived
(1) 客户端测试
[root@client ~]# telnet 192.168.10.222 12000
Trying 192.168.10.222...
Connected to 192.168.10.222.
Escape character is '^]'.

get test_key
END

set test_key 0 0 10
test_value
STORED

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.

(2) 停止srv1的keepalived服务[模拟节点故障]
[root@srv1 ~]# systemctl stop keepalived

(3) 客户端测试HA机制生效
[root@client ~]# telnet 192.168.10.222 12000
Trying 192.168.10.222...
Connected to 192.168.10.222.
Escape character is '^]'.

get test_key
END

set test_key 0 0 10
test_value
STORED

get test_key
VALUE test_key 0 10
test_value
END

quit
Connection closed by foreign host.