keepalived手册中未更新的功能挖掘及使用介绍_李小红_新浪博客
vrrp_script chk_sshd {
script "killall -0 sshd" # cheaper than pidof
interval 2 # check every 2 seconds
weight -4 # default prio: -4 if KO
}
vrrp_script chk_haproxy {
script "killall -0 haproxy" # cheaper than pidof
interval 2 # check every 2 seconds
}
vrrp_script chk_http_port {
script "/tcp/127.0.0.1/80" # connects and exits
interval 1 # check every second
weight -2 # default prio: -2 if connect fails
}
vrrp_script chk_https_port {
script "/tcp/127.0.0.1/443"
interval 1
weight -2
}
vrrp_script chk_smtp_port {
script "/tcp/127.0.0.1/25"
interval 1
weight -2
}
vrrp_instance VI_1 {
interface eth0 state MASTER virtual_router_id 51 priority 100 virtual_ipaddress {
192.168.200.18/25
}
track_interface {
eth1 weight 2 # prio = +2 if UP
eth2 weight -2 # prio = -2 if DOWN
eth3 # no weight, fault if down
}
track_script {
chk_sshd # use default weight from the script
chk_haproxy weight 2 # +2 if process is present
chk_http_port
chk_https_port
chk_smtp_port
}
}
vrrp_instance VI_2 {
interface eth1 state MASTER virtual_router_id 52 priority 100 virtual_ipaddress {
192.168.201.18/26
}
track_interface {
eth0 weight 2 # prio = +2 if UP
eth2 weight -2 # prio = -2 if DOWN
eth3 # no weight, fault if down
}
track_script {
chk_haproxy weight 2
chk_http_port
chk_https_port
chk_smtp_port
}
}
track_script指定检查脚本，定期运行它们来改变优先级，并最终引发主备切换。如果配过交换机的vrrp/hsrp部分的话，应该对这个功能比较熟悉
2、notify_stop
keepalived停止运行前运行notify_stop指定的脚本
下面是我这边应用上面两个功能介绍：
1、两台双master台数据库，用keepalivd的vrrp模式给客户端提供一个HA的虚拟IP
这个要求检查mysql数据库的状态，如果mysql出现问题，就降低优先级，这样虽然机器正常，也会引发新一轮的master选举，以保证mysql服务的高可用性
先定义两个检查脚本
vrrp_script chk_mysqld {
}
vrrp_script chk_schedown {
}
上面的chk_schedown脚本，给管理员提供一个切换的地方，如果管理员在master上手工touch /var/run/down，这样，流量会比这台机器上切走了。
安装配置keepalived 使nginx高可用
wget ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.35.tar.gz
tar -zxvf pcre-8.35.tar.gz
cd pcre-8.35
./configure
make
make install
wget http://zlib.net/zlib-1.2.8.tar.gz
tar -zxvf zlib-1.2.8.tar.gz
cd zlib-1.2.8
./configure
make
make install
wget http://nginx.org/download/nginx-1.7.0.tar.gz
tar -zvxf nginx-1.7.0.tar.gz
cd nginx1.7.0
./configure --with-pcre=/root/pcre-8.35 --with-zlib=/root/zlib-1.2.8
make && make install
yum install openssl-devel
wget http://www.keepalived.org/software/keepalived-1.2.12.tar.gz
vi /etc/keepalived/keepalived.conf
10.124.55.134:
global_defs {
notification_email {
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "/opt/nginx_pid.sh" ############该脚本我们在后面书写
interval 2
weight 2
}
vrrp_instance VI_1 {
state MASTER ############ 辅机为 BACKUP
interface eth0
virtual_router_id 51
mcast_src_ip 10.124.55.134
priority 102 ########### 权值要比 back 高
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port ### 执行监控的服务
}
virtual_ipaddress {
10.124.55.150 ############ 此处的虚拟IP 地址即 我们web所 ####要访问的IP地址 必须在同一网段
}
}
10.124.55.135:
global_defs {
notification_email {
}
notification_email_from [email protected]
smtp_server 127.0.0.1
smtp_connect_timeout 30
router_id LVS_DEVEL
}
vrrp_script chk_http_port {
script "/opt/nginx_pid.sh" ############该脚本我们在后面书写
interval 2
weight 2
}
vrrp_instance VI_1 {
state BACKUP ############ 辅机为 BACKUP
interface eth0
virtual_router_id 51
mcast_src_ip 10.124.55.135
priority 105 ########### 权值要比 master 低
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
track_script {
chk_http_port ### 执行监控的服务
}
virtual_ipaddress {
10.124.55.150 ############ 此处的虚拟IP 地址即 我们web所 ####要访问的IP地址 必须在同一网段
}
}
vi /opt/nginx_pid.sh
输入以下配置
nginxpid=`ps -C nginx --no-header | wc -l`
if [ $nginxpid -eq 0 ];then
/usr/local/nginx/sbin/nginx
sleep 5
if [ `ps -C nginx --no-header | wc -l` -eq 0 ];then
/etc/init.d/keepalived stop
fi
fi
IBM IPV6 Can Cause Poor Java Performance - United States
Problem(Abstract)
If the entire network is not IPv6-enabled or capable, users may find that Java programs perform poorly.
Resolving the problem
This document explains that if the entire network is not IPv6-enabled or capable, users may find that Java programs perform poorly.
On IBM i 6.1 and 7.1, the default JVM is the IBM Technology for Java (J9). This JVM runs in the PASE environment. When IPv6 is enabled (which is the default), each DNS entry is checked to see if it is IPv6-capable. When PASE hits a slow or unresponsive DNS entry, it will wait for a reply or timeout. A java thread dump (javacore) will confirm that IPv6 is the source of the poor performance. The stack will show "Inet6AddressImpl" as shown below:
...
at java/net/Inet6AddressImpl.lookupAllHostAddr(Native Method)
at java/net/InetAddress$2.lookupAllHostAddr(InetAddress.java:949)
at java/net/InetAddress.getAddressFromNameService(InetAddress.java:1318)
at java/net/InetAddress.getLocalHost(InetAddress.java:1505)
...
Resolution:
Disable IPv6 at JVM invocation by using the following java properties:
o -Dcom.ibm.cacheLocalHost=true
o -Djava.net.preferIPv4Stack=true
o -Djava.net.preferIPv6Addresses=false
Note: These properties can be passed as command-line arguments or added to a SystemDefault.properties file.