keepalived是由C语言编写的路由软件，是lvs的扩展项目，主要用作RealServer的健康状态检查以及LoadBalance主机和BackUP主机之间failover的实现。keepalived是一个类似于layer3, 4 & 7交换机制的软件，也就是我们平时说的第3层、第4层和第7层交换。本文主要介绍了其安装过程供大家参考。
1、获取安装软件
下载地址：http://www.keepalived.org/download.html
可以直接下载最新的版本1.2.13，也可以通过wget自动下载
# wget http://www.keepalived.org/software/keepalived-1.2.13.tar.gz
2、安装前提
a、确保ipvs已经被安装 #如下，执行ipvsadm检查ipvs是否已经安装(当前大多数Linux缺省已安装) [root@HKBO ~]# ipvsadm IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn #检查当前加载的内核模块，看是否存在ip_vs模块 [root@HKBO ~]# lsmod|grep ip_vs ip_vs 122113 0 b、安装相应的依赖包 # yum -y install gcc gcc-c++ gcc-g77 ncurses-devel bison libaio-devel \ > cmake libnl* libpopt* popt-static openssl-devel
3、安装keepalived
[root@HKBO ~]# more /etc/issue
CentOS release 5.9 (Final)
# mkdir /usr/local/keepalived
# cd /usr/local/src
# wget http://www.keepalived.org/software/keepalived-1.2.13.tar.gz
# tar -xvf keepalived-1.2.13.tar.gz
# cd keepalived-1.2.13
# ./configure --disable-fwmark --prefix=/usr/local/keepalived
...............
Keepalived configuration
------------------------
Keepalived version : 1.2.13
Compiler : gcc
Compiler flags : -g -O2 -DETHERTYPE_IPV6=0x86dd
Extra Lib : -lssl -lcrypto -lcrypt
Use IPVS Framework : Yes
IPVS sync daemon support : Yes
IPVS use libnl : No
fwmark socket support : No
Use VRRP Framework : Yes
Use VRRP VMAC : No
SNMP support : No
SHA1 support : No
Use Debug flags : No
# make && make install
# ls /usr/local/keepalived/ #查看安装完成后，生成了4个目录
bin etc sbin share
# cd /usr/local/keepalived/etc
[root@HKBO etc]# tree
.
|-- keepalived
| |-- keepalived.conf #keepalived的配置样例
| `-- samples
| |-- client.pem
| |-- dh1024.pem
| |-- keepalived.conf.HTTP_GET.port
| |-- keepalived.conf.IPv6
| |-- keepalived.conf.SMTP_CHECK
| |-- keepalived.conf.SSL_GET
| |-- keepalived.conf.fwmark
| |-- keepalived.conf.inhibit
| |-- keepalived.conf.misc_check
| |-- keepalived.conf.misc_check_arg
| |-- keepalived.conf.quorum
| |-- keepalived.conf.sample
| |-- keepalived.conf.status_code
| |-- keepalived.conf.track_interface
| |-- keepalived.conf.virtual_server_group
| |-- keepalived.conf.virtualhost
| |-- keepalived.conf.vrrp
| |-- keepalived.conf.vrrp.localcheck
| |-- keepalived.conf.vrrp.lvs_syncd
| |-- keepalived.conf.vrrp.routes
| |-- keepalived.conf.vrrp.scripts
| |-- keepalived.conf.vrrp.static_ipaddress
| |-- keepalived.conf.vrrp.sync
| |-- root.pem
| `-- sample.misccheck.smbcheck.sh
|-- rc.d
| `-- init.d
| `-- keepalived
`-- sysconfig
`-- keepalived
# cd /usr/local/keepalived/sbin
# ./keepalived --help #获取keepalived的一些帮助
Usage: ./keepalived [OPTION...]
-f, --use-file=FILE Use the specified configuration file
-P, --vrrp Only run with VRRP subsystem
-C, --check Only run with Health-checker subsystem
-l, --log-console Log messages to local console
-D, --log-detail Detailed log messages
-S, --log-facility=[0-7] Set syslog facility to LOG_LOCAL[0-7]
-V, --dont-release-vrrp Don't remove VRRP VIPs and VROUTEs on daemon stop
-I, --dont-release-ipvs Don't remove IPVS topology on daemon stop
-R, --dont-respawn Don't respawn child processes
-n, --dont-fork Don't fork the daemon process
-d, --dump-conf Dump the configuration data
-p, --pid=FILE Use specified pidfile for parent process
-r, --vrrp_pid=FILE Use specified pidfile for VRRP child process
-c, --checkers_pid=FILE Use specified pidfile for checkers child process
-v, --version Display the version number
-h, --help Display this help message
# mkdir /etc/keepalived/
# cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/
# 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/keepalived/sbin/keepalived /sbin/
# service keepalived restart
Stopping keepalived: [FAILED]
Starting keepalived: [ OK ]
# service keepalived status
keepalived (pid 12092) is running...
# chkconfig keepalived on
# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:84:04:2c brd ff:ff:ff:ff:ff:ff
inet 192.168.1.66/24 brd 192.168.1.255 scope global eth0
inet 192.168.200.16/32 scope global eth0
inet 192.168.200.17/32 scope global eth0
inet 192.168.200.18/32 scope global eth0
inet6 fe80::250:56ff:fe84:42c/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
4、有关keepalived.conf的配置项
[root@HKBO keepalived]# more keepalived.conf
! Configuration File for keepalived
#全局定义块，包含邮件定义部分，
global_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 LVS_DEVEL //负载均衡器标识，在一个网络内，它应该是唯一的
}
#VRRP实例定义块，负责负载均衡器之间的失败切换
vrrp_instance VI_1 {
state MASTER //只有MASTER和BACKUP 2种状态，主为MASTER，从为BACKUP，使用大写
interface eth0 //监控的网络接口
virtual_router_id 51 //同一实例下virtual_router_id必须相同
priority 100 //定义优先级，数字越大，优先级越高
advert_int 1 //MASTER与BACKUP负载均衡器之间同步检查的时间间隔，单位是秒
authentication { //验证类型和密码
auth_type PASS
auth_pass 1111
}
virtual_ipaddress { //虚拟ip地址virtual_ipaddress,可以定义多个
192.168.200.16
192.168.200.17
192.168.200.18
}
}
#虚拟服务器定义块
virtual_server 192.168.200.100 443 { //定义虚拟服务器
delay_loop 6 //delay_loop，健康检查时间间隔，单位是秒
lb_algo rr //负载调度算法，这里设置为rr，即轮询算法，互联网应用常使用wlc或rr
lb_kind NAT //负载均衡转发规则。一般包括DR,NAT,TUN3种，在我的方案中，都使用DR的方式
nat_mask 255.255.255.0 //子网掩码
persistence_timeout 50 //会话保持时间，单位是秒（可以适当延长时间以保持session）
protocol TCP //转发协议类型，有tcp和udp两种
real_server 192.168.201.100 443 { //真实服务器IP及端口
weight 1 //默认为1,0为失效
SSL_GET {
url {
path /
digest ff20ad2481f97b1754ef3e12ecd3a9cc
}
url {
path /mrtg/
digest 9b3a0c85a887a256d6939da88aabd8cd
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
virtual_server 10.10.10.2 1358 {
delay_loop 6
lb_algo rr
lb_kind NAT
persistence_timeout 50
protocol TCP
sorry_server 192.168.200.200 1358
real_server 192.168.200.2 1358 {
weight 1
HTTP_GET {
url {
path /testurl/test.jsp
digest 640205b7b0fc66c1ea91c463fac6334d
}
url {
path /testurl2/test.jsp
digest 640205b7b0fc66c1ea91c463fac6334d
}
url {
path /testurl3/test.jsp
digest 640205b7b0fc66c1ea91c463fac6334d
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
real_server 192.168.200.3 1358 {
weight 1
HTTP_GET {
url {
path /testurl/test.jsp
digest 640205b7b0fc66c1ea91c463fac6334c
}
url {
path /testurl2/test.jsp
digest 640205b7b0fc66c1ea91c463fac6334c
}
connect_timeout 3
nb_get_retry 3
delay_before_retry 3
}
}
}
5、配置主备keepalived
a、配置主备keepalived
#主，以下主要列出keepalived.conf差异部分
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.220
192.168.1.230
}
}
#备，以下主要列出keepalived.conf差异部分
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.220
192.168.1.230
}
}
b、测试主备keepalived
#启动主服务器上的keepalived服务
[root@MASTER ~]# service keepalived start
Starting keepalived: [ OK ]
[root@SZ-SYS-APP01 ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:84:1f:37 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.65/24 brd 192.168.1.255 scope global eth0
inet 192.168.1.220/32 scope global eth0 #可以看到220和230的虚IP
inet 192.168.1.230/32 scope global eth0
inet6 fe80::250:56ff:fe84:1f37/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
#启动备用服务器上的keepalived服务
[root@BACKUP ~]# service keepalived start
Starting keepalived: [ OK ]
#下面的查询结果中，虚IP220和230并为出现在备用服务器
[root@HKBO ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:84:04:2c brd ff:ff:ff:ff:ff:ff
inet 192.168.1.66/24 brd 192.168.1.255 scope global eth0
inet6 fe80::250:56ff:fe84:42c/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
#关闭主服务上的keepalived服务，观察vip是否会漂移到备用服务
[root@MASTER ~]# service keepalived stop
Stopping keepalived: [ OK ]
[root@MASTER ~]# ip addr #关闭后，该命令可以看到220和230的虚IP已经不存在于主服务器
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:84:1f:37 brd ff:ff:ff:ff:ff:ff
inet 192.168.1.65/24 brd 192.168.1.255 scope global eth0
inet6 fe80::250:56ff:fe84:1f37/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
#此时在备用服务器上查看到了漂移的vip地址
[root@BACKUP ~]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
link/ether 00:50:56:84:04:2c brd ff:ff:ff:ff:ff:ff
inet 192.168.1.66/24 brd 192.168.1.255 scope global eth0
inet 192.168.1.220/32 scope global eth0
inet 192.168.1.230/32 scope global eth0
inet6 fe80::250:56ff:fe84:42c/64 scope link
valid_lft forever preferred_lft forever
3: sit0: <NOARP> mtu 1480 qdisc noop
link/sit 0.0.0.0 brd 0.0.0.0
#如果再次启动主服务器上的keepalived服务，则会vip自动漂移到主服务器，不再验证。
#Author : Leshami
#Blog ：http://blog.csdn.net/leshami
6、配置双主keepalived
双主的keepalived方式实际上是互为主备，以避免单点故障
#配置主备keepalived
MasterA: 192.168.1.65, VirtualIP: 192.168.1.220
MasterB: 192.168.1.66, VirtualIP: 192.168.1.230
#主，以下主要列出keepalived.conf差异部分
vrrp_instance VI_1 {
state MASTER
interface eth0
virtual_router_id 51
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.220
}
}
vrrp_instance VI_2 {
state BACKUP
interface eth0
virtual_router_id 52
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.230
}
}
#备，以下主要列出keepalived.conf差异部分
vrrp_instance VI_1 {
state BACKUP
interface eth0
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.220
}
}
vrrp_instance VI_2 {
state MASTER
interface eth0
virtual_router_id 52
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.1.230
}
}
#从上面的配置文件中可以看出，实际上是增加了一个vrrp实例
#验证过程略
7、编译时的错误No SO_MARK
#如果在编译时碰到了No SO_MARK错误，如下
# ./configure
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables...
checking whether we are cross compiling... no
checking for suffix of object files... o
...........
checking for nl_socket_alloc in -lnl-3... no
checking for nl_socket_modify_cb in -lnl... no
configure: WARNING: keepalived will be built without libnl support.
checking for kernel version... 2.6.18
checking for IPVS syncd support... yes
checking for kernel macvlan support... no
checking whether SO_MARK is declared... no
configure: error: No SO_MARK declaration in headers
#可以通过增加disable-fwmark参数来解决
--disable-fwmark compile without SO_MARK support