DRBD+Heartbeat+Mysql

MySQL high availability cluster with DRBD+Heartbeat+MySQL - You can also download the cleaner version of this document by clicking here - Download here 1) Set up hostnames and network On all Nodes. Please copy this file on all servers/nodes Run this on db1 and db2 server nano /etc/hosts ##### IP's of MySQL DB servers ##### 192.168.1.210 db1.wcws.net db1 192.168.1.211 db2.wcws.net db2 Run this on db1 and db2 server ssh-keygen ssh-keygen ssh-copy-id root@db2 ssh-copy-id root@db1 In my configuration I, Installed CentOS with just one hard drive on both servers and the drive I just to boot centos was 10GB therefore I have added another drive with 10GB Space space, please note each server hard drive must be identical in size other wise you will run into problems. I am assuming you have already added a secondary disk with 10GB so lets start some serious configuration and feel yourself proud. Following these steps and you will thank me later # nano /etc/selinux/config SELINUX=disabled chkconfig iptables off Make sure your firewall is OFF – you can also do that by running setup command on your shell and follow the steps Partion setup on both server identical same with fdisk Once I added a drive my drive was named as /dev/sdb – please verify that before you do any thing So in my server after I added an additional disk my drive was named as /dev/sdb which you can also verify by running fdisk –l Lets create partition fdisk /dev/sdb primary partition – press p Partition number (1-4): 1 Press ENTER FOR ALL DEFAULT SETTINGS Press t and type 8e – HIT ENTER TYPE w to write  once done simply type partprobe Secondary we will create some logical volume pvcreate /dev/sdb1 vgcreate vgdb /dev/sdb1 Create Logical volume partition lvcreate -L +10000M -n lvdb vgdb RUN ABOVE STEP ON BOTH DB1 & DB2 Server and please make sure the drive size are exact and accurate. Once everything is done simply reboot your server Now the fun part J YEA BABY rpm -Uvh http://elrepo.org/elrepo-release-6-4.el6.elrepo.noarch.rpm nano /etc/yum.repos.d/elrepo.repo name=ELRepo.org Community Enterprise Linux Repository - el6 baseurl=http://elrepo.org/linux/elrepo/el6/$basearch/ mirrorlist=http://elrepo.org/mirrors-elrepo.el6 enabled=0 gpgcheck=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-elrepo.org protect=0

rpm –Uvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

yum --enablerepo=elrepo install drbd83-utils kmod-drbd83 mysql mysql-server heartbeat heartbeat-pils heartbeat-stonith –y Once installed simply run the following command as we don’t want mysql to start on boot time chkconfig mysqld off chkconfig heartbeat off chkconfig drbd off now reboot your server – PLEASE NOTE ALL ABOVE COMMANDS MUST BE RUN ON BOTH DB1 and DB2 Server. Now your servers are up and running do the following modprobe drbd modprobe drbd echo "modprobe drbd" > /etc/rc.local echo "modprobe drbd" > /etc/rc.local nano /etc/drbd.conf and delete all the lines from your current drbd.conf file and copy the following

global {usage-count no; } common { syncer { rate 3M; } } resource r0 { protocol C; handlers { split-brain "/usr/lib/drbd/notify-split-brain.sh root"; 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 { degr-wfc-timeout 120; } disk { on-io-error detach; } net { # The following lines are dedicated to handle # split-brain situations (e.g., if one of the nodes fails) after-sb-0pri discard-zero-changes; # If both nodes are secondary, just make one of them primary after-sb-1pri discard-secondary; # If one is primary, one is not, trust the primary node after-sb-2pri call-pri-lost-after-sb; # If there are two primaries, make the unchanged one secondary rr-conflict disconnect; } syncer { rate 3M; al-extents 257; } on db1.wcws.net { device /dev/drbd0; disk /dev/vgdb/lvdb; address 192.168.1.210:7788; #DEFINE YOUR DB1 IP flexible-meta-disk internal; } on db2.wcws.net { device /dev/drbd0; disk /dev/vgdb/lvdb; address 192.168.1.211:7788; #DEFINE YOUR DB2 IP flexible-meta-disk internal; } }

Once above file is saved – now simply copy that file to DB2 server scp /etc/drbd.conf db2:/etc/ Run the following on both servers echo "modprobe drbd" >> /etc/rc.local now lets start drbd on both db1 and db2 service drbd start Run the following commands on both db1 & db2 drbdadm create-md r0 drbdadm attach r0 drbdadm syncer r0 drbdadm connect r0 On Primary Node only #drbdadm -- --overwrite-data-of-peer primary r0 On both Nodes:  #drbdadm up all #drbdadm up all On Primary Node only #drbdadm -- primary all #### ON Node one Only #### You are done with DRBD Part – now check the sync status by #watch cat /proc/drbd only on db1 ########## Primary Node ######## #mkfs.ext3 /dev/drbd0 #mkdir /data/ #mount /dev/drbd0 /data/ On db2 ####### Secondry Node ####### #mkdir /data nano /etc/ha.d/ha.cf ## Create this file and copy this text ## logfacility local0 keepalive 2
#deadtime 30 # USE THIS!!! deadtime 10 bcast eth0 #serial /dev/ttyS0 baud 19200 auto_failback off node db1.wcws.net node db2.wcws.net   Server db1   #vi /etc/ha.d/haresources db1.wcws.net IPaddr::192.168.1.219/32/eth0 drbddisk::r0 Filesystem::/dev/drbd0::/data::ext3 mysqld Server db2:  #vi /etc/ha.d/haresources db2.wcws.net IPaddr::192.168.1.219/32/eth0 drbddisk::r0 Filesystem::/dev/drbd0::/data::ext3 mysqld On Both Servers:  #vi /etc/ha.d/authkeys auth 3 3 md5 wcws #chmod 600 /etc/ha.d/authkeys #scp /etc/ha.d/authkeys db2:/etc/ha.d/authkeys #chkconfig heartbeat on

Mysql Configuration.    cp /etc/my.cnf /etc/my.cnf.orig   vi /etc/my.cnf   # datadir=/var/lib/mysql datadir=/data/mysql #socket=/var/lib/mysql/mysql.sock socket=/data/mysql/mysql.sock # Default to using old password format for compatibility with mysql 3.x # clients (those using the mysqlclient10 compatibility package). old_passwords=1   user=mysql #basedir=/var/lib basedir=/data   log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid   socket=/data/mysql/mysql.sock

  Run the following command on both servers db1 & db2 chkconfig drbd on Copy my.cnf file on db2 server scp /etc/my.cnf db2:/etc/  Now simply restart your server and connect your web server to your FLOATING IP which we define in haresource file i.e. 192.168.1.219 – Connect to MYSQL setup your root password after you create your database In MySQL simply run this command to give grant access to your DB GRANT ALL ON store.* TO root@'192.168.1.212' IDENTIFIED BY 'YOURMYSQLROOTPASSWORD'; In my case 212 IP is – IP of my web server   One last thing nano /etc/aliases go at the very bottom and on both db1 & db2 server and change root  like this root: [email protected] - Congrats you just setup a DRBD HIGH AVAILABILITY Please do leave me comments and let me know what you think about this tutorial and if that help's you - I would love to get your feedbacks.