DRBD-MYSQL分布式块设备实现高可用
DRBD是一个用软件实现的、无共享的、服务器之间镜像块设备内容的存储复制解决方案。 DRBD Logo数据镜像：实时、透明、同步（所有服务器都成功后返回）、异步（本地服务器成功后返回）。DBRD的核心功能通过Linux的内核实现，最接近系统的IO栈，但它不能神奇地添加上层的功能比如检测到EXT3文件系统的崩溃。DBRD的位置处于文件系统以下，比文件系统更加靠近操作系统内核及IO栈。
环境：
192.168.5.101 cml1
192.168.5.102 cml2
[root@cml1 ~]# cat /etc/hosts
127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6
192.168.5.101 cml1 wwwNaNl1.com
192.168.5.102 cml2 wwwNaNl2.com
192.168.5.104 cml3 wwwNaNl3.com
192.168.5.105 cml4 wwwNaNl4.com
[root@cml1 ~]# ssh-keygen
[root@cml1 ~]# ssh-copy-id cml2
[root@cml1 ~]# crontab -l
*/5 * * * * ntpdate cn.pool.ntp.org
[root@cml1 ~]# rpm --importhttps://www.elrepo.org/RPM-GPG-KEY-elrepo.org
[root@cml1 ~]# rpm -Uvh http://www.elrepo.org/elrepo-release-7.0-2.el7.elrepo.noarch.rpm
[root@cml1 ~]# yum install -y kmod-drbd84 drbd84-utils
/etc/drbd.conf #主配置文件
/etc/drbd.d/global_common.conf#全局配置文件
[root@cml1 ~]# cat /etc/drbd.conf
# You can find an example in /usr/share/doc/drbd.../drbd.conf.example
include"drbd.d/global_common.conf";
include "drbd.d/*.res";
[root@cml1 ~]# vim/etc/drbd.d/global_common.conf
global {
usage-count no; #是否参加DRBD使用统计，默认为yes。官方统计drbd的装机量
#minor-count dialog-refresh disable-ip-verification
}
common {
protocol C; #使用DRBD的同步协议
handlers {
pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh;/usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ;reboot -f";
pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh;/usr/lib/drbd/notify-emergency-reboot.sh; echo b > /proc/sysrq-trigger ;reboot -f";
local-io-error "/usr/lib/drbd/notify-io-error.sh;/usr/lib/drbd/notify-emergency-shutdown.sh; echo o > /proc/sysrq-trigger ;halt -f";
}
startup {
# wfc-timeout degr-wfc-timeout outdated-wfc-timeout wait-after-sb
}
options {
# cpu-mask on-no-data-accessible
}
disk {
on-io-error detach; #配置I/O错误处理策略为分离
# size max-bio-bvecs on-io-error fencing disk-barrier disk-flushes
# disk-drain md-flushes resync-rate resync-after al-extents
# c-plan-ahead c-delay-target c-fill-target c-max-rate
# c-min-rate disk-timeout
}
net {
# protocol timeout max-epoch-size max-buffers unplug-watermark
# connect-int ping-int sndbuf-size rcvbuf-size ko-count
# allow-two-primaries cram-hmac-alg shared-secret after-sb-0pri
# after-sb-1pri after-sb-2pri always-asbp rr-conflict
# ping-timeout data-integrity-alg tcp-cork on-congestion
# congestion-fill congestion-extents csums-alg verify-alg
# use-rle
}
syncer {
rate 1024M; #设置主备节点同步时的网络速率
}
}
注释： on-io-error 策略可能为以下选项之一
detach 分离：这是默认和推荐的选项，如果在节点上发生底层的硬盘I/O错误，它会将设备运行在Diskless无盘模式下
pass_on：DRBD会将I/O错误报告到上层，在主节点上，它会将其报告给挂载的文件系统，但是在此节点上就往往忽略（因此此节点上没有可以报告的上层）
-local-in-error：调用本地磁盘I/O处理程序定义的命令；这需要有相应的local-io-error调用的资源处理程序处理错误的命令；这就给管理员有足够自由的权力命令命令或是脚本调用local-io-error处理I/O错误定义一个资源
[root@cml1 ~]# cat/etc/drbd.d/mysql.res
resource mysql { ##资源名称
protocol C; ##使用协议
meta-disk internal;
device /dev/drbd1; ##DRBD设备名称
syncer {
verify-alg sha1; ##加密算法
}
net {
allow-two-primaries;
}
on cml1 {
disk /dev/sdb1; ##drbd使用的磁盘分区为“mysql”（可以不想同的磁盘名字）
address 192.168.5.101:7789; ##设置DRBD监听地址的端口
}
on cml2 {
disk /dev/sdb1;
address 192.168.5.102:7789;
}
}
[root@cml1 ~]# scp -rp /etc/drbd.d/*cml2:/etc/drbd.d/
##然后在两台机器上安装mariadb
[root@cml1 ~]# yum install -ymariadb-server mariadb
[root@cml1 ~]# mkdir /data/
[root@cml1 ~]# cat /etc/my.cnf
[mysqld]
datadir=/data
socket=/var/lib/mysql/mysql.sock
# Disabling symbolic-links is recommendedto prevent assorted security risks
symbolic-links=0
# Settings user and group are ignored whensystemd is used.
# If you need to run mysqld under adifferent user or group,
# customize your systemd unit file formariadb according to the
# instructions inhttp://fedoraproject.org/wiki/Systemd
[mysqld_safe]
log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid
#
# include all files from the configdirectory
#
!includedir /etc/my.cnf.d
[root@cml1 ~]# chown mysql:mysql /data/
[root@cml1 ~]# drbdadm create-md mysql
initializing activity log
initializing bitmap (160 KB) to all zero
Writing meta data...
New drbd meta data block successfullycreated.
[root@cml1 ~]# modprobe drbd
##查看内核是否已经加载了模块：
[root@cml1 drbd.d]# lsmod | grep drbd
drbd 396875 1
libcrc32c 12644 4 xfs,drbd,ip_vs,nf_conntrack
###
[root@cml1 ~]# drbdadm up mysql
[root@cml1 ~]# drbdadm -- --force primarymysql
##查看状态：
[root@cml1 ~]# cat /proc/drbd
version: 8.4.10-1 (api:1/proto:86-101)
GIT-hash: a4d5de01fffd7e4cde48a080e2c686f9e8cebf4cbuild by mockbuild@, 2017-09-15 14:23:22
1:cs:WFConnection ro:Primary/Unknown ds:UpToDate/DUnknown C r----s
ns:0 nr:0 dw:0 dr:912 al:8 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:foos:5240636
[root@cml2 ~]# chown mysql:mysql /data/
[root@cml2 ~]# drbdadm create-md mysql
[root@cml2 ~]# modprobe drbd
[root@cml2 ~]# drbdadm up mysql
在从上面可以查看数据同步的状态：
[root@cml2 ~]# cat /proc/drbd
version: 8.4.10-1 (api:1/proto:86-101)
GIT-hash:a4d5de01fffd7e4cde48a080e2c686f9e8cebf4c build by mockbuild@, 2017-09-1514:23:22
1:cs:SyncTarget ro:Secondary/Primary ds:Inconsistent/UpToDate C r-----
ns:0 nr:1513472 dw:1513472 dr:0 al:8 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:foos:3727164
[====>...............] sync‘ed: 29.0% (3636/5116)M
finish: 0:01:32 speed: 40,192 (38,804) want: 102,400 K/sec
[root@cml1 ~]# mkfs.ext4 /dev/drbd1
meta-data=/dev/drbd1 isize=512 agcount=4, agsize=327540 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=0, sparse=0
data = bsize=4096 blocks=1310159,imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
log =internal log bsize=4096 blocks=2560,version=2
= sectsz=512 sunit=0 blks,lazy-count=1
realtime =none extsz=4096 blocks=0, rtextents=0
[root@cml1 ~]# mount /dev/drbd1 /mnt
[root@cml1 ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/cl-root 17G 6.9G 11G 41% /
devtmpfs 588M 0 588M 0% /dev
tmpfs 599M 0 599M 0% /dev/shm
tmpfs 599M 34M 565M 6% /run
tmpfs 599M 0 599M 0% /sys/fs/cgroup
/dev/sda1 1014M 168M 847M 17% /boot
/dev/drbd1 5.0G 33M 5.0G 1% /mnt
注####要想使得从可以挂载，我们必须，先把主切换成丛，然后再到从上面挂载：
有如下资源：
资源的连接状态；一个资源可能有以下连接状态中的一种
StandAlone 独立的：网络配置不可用；资源还没有被连接或是被管理断开（使用 drbdadm disconnect 命令），或是由于出现认证失败或是脑裂的情况
Disconnecting 断开：断开只是临时状态，下一个状态是StandAlone独立的
Unconnected 悬空：是尝试连接前的临时状态，可能下一个状态为WFconnection和WFReportParams
Timeout 超时：与对等节点连接超时，也是临时状态，下一个状态为Unconected悬空
BrokerPipe：与对等节点连接丢失，也是临时状态，下一个状态为Unconected悬空
NetworkFailure：与对等节点推动连接后的临时状态，下一个状态为Unconected悬空
ProtocolError：与对等节点推动连接后的临时状态，下一个状态为Unconected悬空
TearDown 拆解：临时状态，对等节点关闭，下一个状态为Unconected悬空
WFConnection：等待和对等节点建立网络连接
WFReportParams：已经建立TCP连接，本节点等待从对等节点传来的第一个网络包
Connected 连接：DRBD已经建立连接，数据镜像现在可用，节点处于正常状态
StartingSyncS：完全同步，有管理员发起的刚刚开始同步，未来可能的状态为SyncSource或PausedSyncS
StartingSyncT：完全同步，有管理员发起的刚刚开始同步，下一状态为WFSyncUUID
WFBitMapS：部分同步刚刚开始，下一步可能的状态为SyncSource或PausedSyncS
WFBitMapT：部分同步刚刚开始，下一步可能的状态为WFSyncUUID
WFSyncUUID：同步即将开始，下一步可能的状态为SyncTarget或PausedSyncT
SyncSource：以本节点为同步源的同步正在进行
SyncTarget：以本节点为同步目标的同步正在进行
PausedSyncS：以本地节点是一个持续同步的源，但是目前同步已经暂停，可能是因为另外一个同步正在进行或是使用命令(drbdadm pause-sync)暂停了同步
PausedSyncT：以本地节点为持续同步的目标，但是目前同步已经暂停，这可以是因为另外一个同步正在进行或是使用命令(drbdadm pause-sync)暂停了同步
VerifyS：以本地节点为验证源的线上设备验证正在执行
VerifyT：以本地节点为验证目标的线上设备验证正在执行
[root@cml1 ~]# cat /proc/drbd
version: 8.4.10-1 (api:1/proto:86-101)
GIT-hash:a4d5de01fffd7e4cde48a080e2c686f9e8cebf4c build by mockbuild@, 2017-09-1514:23:22
1:cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r-----
ns:10526345 nr:340312 dw:392669 dr:10488683 al:24 bm:0 lo:0 pe:0 ua:0ap:0 ep:1 wo:f oos:0
[root@cml1 etc]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 Connected Secondary/Primary UpToDate/UpToDate
You have new mail in /var/spool/mail/root
node3现在是master状态：
[root@cml2 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 Connected Primary/Secondary UpToDate/UpToDate /test xfs 5.0G 33M 5.0G 1%
You have new mail in /var/spool/mail/root
[root@cml2 ~]# iptables -P INPUT DROP. ##注意这里要先开启22端口：
###我们查看一下cml1的状态：
[root@cml1 etc]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 WFConnection Secondary/Unknown UpToDate/DUnknown
You have new mail in /var/spool/mail/root
###现在是Unknown状态，是不可用的：
[root@cml1 etc]# drbdadm primary mysql
[root@cml1 etc]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 WFConnection Primary/Unknown UpToDate/DUnknown
[root@cml1 etc]# mount /dev/drbd1 /mnt/
[root@cml1 etc]# ls /mnt/
xiaoluo.txt
iptables -P INPUT ACCEPT
##查看两个结点的状态：
[root@cml1 etc]# drbdadm role mysql
Primary/Unknown
[root@cml2 ~]# drbdadm role mysql
Primary/Unknown
##查看两个的链接状态：
[root@cml1 etc]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 StandAlone Primary/Unknown UpToDate/DUnknown /mnt xfs 5.0G 33M 5.0G 1%
[root@cml2 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 StandAlone Primary/Unknown UpToDate/DUnknown /test xfs 5.0G 33M 5.0G 1%
[root@cml1 ~]# umount /mnt/
[root@cml1 ~]# drbdadm disconnect mysql
??: Failure: (162) Invalid configurationrequest
additional info from kernel:
unknown connection
Command ‘drbdsetup-84 disconnectipv4:192.168.113.143:7789 ipv4:192.168.113.144:7789‘ terminated with exit code10
要把mariadb stop掉才可以切成secondary
[root@cml1 ~]# drbdadm secondary mysql
[root@cml1 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 StandAlone Secondary/Unknown UpToDate/DUnknown
[root@cml1 ~]# drbdadm connect--discard-my-data mysql ##在从主机上做
##现在我们查看一下集群结点还是不能用的：
[root@cml1 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 WFConnection Secondary/Unknown UpToDate/DUnknown
[root@cml2 ~]# drbdadm connect mysql ##在主的主机上面做
##然后我们再查看一下状态：
[root@cml2 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 Connected Primary/Secondary UpToDate/UpToDate /test xfs 5.0G 33M 5.0G 1%
[root@cml1 ~]# drbd-overview
NOTE: drbd-overview will be deprecatedsoon.
Please consider using drbdtop.
1:mysql/0 Connected Secondary/Primary UpToDate/UpToDate
本文出自 “第一个legehappy51cto博客” 博客，请务必保留此出处http://legehappy.blog.51cto.com/13251607/1975804
原文：http://legehappy.blog.51cto.com/13251607/1975804