DRBD MySQL HowTo

From ClusterLabs

Jump to: navigation, search

Mysql- apache- Pacemaker- openais- drbd active/passive cluster with debian lenny


First we need 2 machines, each with 2 NIC's. On both node' s we install debian with 5 partitions:

/boot
/ 
/swap
/drbd for the meta data
/service the partition you want to mirror

Now we have to do some basic steps.

zero out the drbd-meta-data partition

dd if=/dev/zero of=/dev/sda7 
umount /dev/sda7 /drbd
nano /etc/fstab 
cause mounting the drbd device will do pacemaker.
proc            /proc           proc    defaults        0       0
/dev/mapper/vol--root-root /               ext3    errors=remount-ro 0       1
/dev/sda1       /boot           ext3    defaults        0       2
#/dev/sda7       /drbd           ext3    defaults        0       2
/dev/sda6       none            swap    sw              0       0
/dev/hda        /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/fd0        /media/floppy0  auto    rw,user,noauto  0       0


/dev/drbd0      /service  ext3    defaults        0       2

Configure both network cards, one for the outside world, the other for the cluster interconnect, which should be a own net. ex.

nano /etc/network/interfaces
The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#allow-hotplug eth0

auto eth0
iface eth0 inet static
address 10.100.100.203
netmask 255.255.255.0
gateway 10.100.100.3
dns-nameservers 10.100.100.3

auto eth1
iface eth1 inet static
address 10.100.101.2
netmask 255.255.255.248
you have to edit
nano /etc/hosts:
10.100.101.1    bart.nopanic.loc bart
10.100.101.2    lisa.nopanic.loc lisa


these hostnames are used in drbd.conf.

fromdrbd.org

We have to install some additional software: make, gcc, build-essential, flex 
After this we beginn to install drbd. Best choice is to do it from source : http://oss.linbit.com/drbd/ and take the latest stable release. 

apt-get install kernel-headers-$(uname -r)

tar xzvf drbd-8.3.2.tar.gz

After changing into your unpacked DRBD sources directory, you should now change into the kernel module subdirectory, simply named drbd, and build the module there: 
cd drbd 
make clean all

cd /usr/src/drbd-x.y.z 
make tools

cd /usr/src/drbd-x.y.z 
make install
cd /usr/src/drbd-x.y.z 
make install-tools
nano /etc/drbd.conf


  on bart {
    device     /dev/drbd0;
    disk       /dev/sdb5;    			#The partition you want to mirror
    address    10.100.101.1:7788;		# the cluster interconnect IP
    meta-disk  /dev/sda7 [0];			#The partition for the meta-data

    # meta-disk is either 'internal' or '/dev/ice/name [idx]'
    #
    # You can use a single block device to store meta-data
    # of multiple DRBD's.
    # E.g. use meta-disk /dev/hde6[0]; and meta-disk /dev/hde6[1];
    # for two different resources. In this case the meta-disk
    # would need to be at least 256 MB in size.
    #
    # 'internal' means, that the last 128 MB of the lower device
    # are used to store the meta-data.
    # You must not give an index with 'internal'.
  }

  on lisa {
    device    /dev/drbd0;
    disk      /dev/sdb5;
    address   10.100.101.2:7788;
    meta-disk /dev/sda7 [0];
  }
}



Copy the drbd.conf it to the other node, it has to be the same on both nodes.

1.Create device metadata. This step must be completed only on initial device creation. It initializes DRBD's metadata: 
For „resource“ you have the resource name you defined in drbd.conf. If this is untouched it should be r0.
drbdadm create-md resource
v08 Magic number not found
Writing meta data...
initialising activity log
NOT initialized bitmap
New drbd meta data block sucessfully created.
success

2.Attach to backing device. This step associates the DRBD resource with its backing device: 
drbdadm attach resource
3.Set synchronization parameters. This step sets synchronization parameters for the DRBD resource: 
drbdadm syncer resource
4.Connect to peer. This step connects the DRBD resource with its counterpart on the peer node: 
drbdadm connect resource

Tip

You may collapse the steps drbdadm attach, drbdadm syncer, and drbdadm connect into one, by using the shorthand command drbdadm up.
5.Observe /proc/drbd. DRBD's virtual status file in the /proc filesystem, /proc/drbd, should now contain information similar to the following:
cat /proc/drbd
version: 8.3.0 (api:88/proto:86-89)
GIT-hash: 9ba8b93e24d842f0dd3fb1f9b90e8348ddb95829 build by buildsystem@linbit, 2008-12-18 16:02:26
1: cs:Connected ro:Secondary/Secondary ds:Inconsistent/Inconsistent C r---
ns:0 nr:0 dw:0 dr:0 al:0 bm:0 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:200768
The Inconsistent/Inconsistent disk state is expected at this point.
By now, DRBD has successfully allocated both disk and network resources and is ready for operation. What it does not know yet is which of your nodes should be used as the source of the initial device synchronization. **

** from drbd.org

On the node which should be the primary:

drbdadm – --overwrite-data-of-peer primary r0

create under / a service directory That drbd can mount you have to edit:

nano /etc/fstab
/dev/drbd0      /service  ext3    defaults        0       2

Now the drbd failover should work.

Pacemaker add to your source.list:

nano /etc/apt/sources.list
For Debian 5.0 (lenny): 
 deb http://people.debian.org/~madkiss/ha-corosync lenny main
For Debian unstable (sid): 
 deb http://people.debian.org/~madkiss/ha-corosync sid main
Once this has been completed, run: 
 apt-get update
Finally, to install Pacemaker simply decide which stack you wish to use and run 
 apt-get install pacemaker-openais

generate key for openais

lisa:~ # ais-keygen
bart:~ # ais-keygen 
nano /etc/ais/openais.conf

        interface {
                # The following values need to be set based on your environment
                ringnumber: 0
                bindnetaddr: 10.100.100.0
                mcastaddr: 226.94.1.1
                mcastport: 5405
        }
}

logging {
        to_stderr: yes
        debug: off
        timestamp: on
        to_file: no
        to_syslog: yes
        syslog_facility: daemon
}

amf {
        mode: disabled
}

service {
        # Load the Pacemaker Cluster Resource Manager
        ver:       0
        name:      pacemaker
        use_mgmtd: yes
}

aisexec {
        user:   root
        group:  root
}
lisa:~ # scp /etc/ais/openais.conf root@bart:/etc/ais/openais.conf 
lisa:~ # /etc/init.d/openais start
bart:~ # /etc/init.d/openais start 


generate a file with:

nano /root/config

copy & paste:

primitive drbd_mysql ocf:linbit:drbd \
        params drbd_resource="r0" \
        op monitor interval="15s"
primitive fs_mysql ocf:heartbeat:Filesystem \
        params device="/dev/drbd/by-res/r0" directory="/service/" fstype="ext3"
primitive ip_mysql ocf:heartbeat:IPaddr2 \
        params ip="10.100.100.200" nic="eth0"
primitive mysqld lsb:mysql
primitive apache lsb:apache2

group mysql fs_mysql ip_mysql mysqld apache 
ms ms_drbd_mysql drbd_mysql \
        meta master-max="1" master-node-max="1" clone-max="2" clone-node-max="1" notify="true"
colocation mysql_on_drbd inf: mysql ms_drbd_mysql:Master
order mysql_after_drbd inf: ms_drbd_mysql:promote mysql:start
property $id="cib-bootstrap-options" \
        no-quorum-policy="ignore" \
        stonith-enabled="false" \
        expected-quorum-votes="2" \
        dc-version="1.0.4-2ec1d189f9c23093bf9239a980534b661baf782d" \
        cluster-infrastructure="openais"

Mysql

aptitude install mysql-server

nano /etc/mysql/my.cnf
	datadir         = /service/mysql  
	bind-address            = 10.100.100.200  # clusterIP

have a look which node is the primary drbd node.:

cat /proc/drbd
lisa:~# cat /proc/drbd
version: 8.3.2 (api:88/proto:86-90)
GIT-hash: dd7985327f146f33b86d4bff5ca8c94234ce840e build by , 2009-09-07 00:18:26
 0: cs:Connected ro:Primary/Secondary ds:UpToDate/UpToDate C r----
    ns:136 nr:336 dw:472 dr:3186 al:6 bm:8 lo:0 pe:0 ua:0 ap:0 ep:1 wo:b oos:0

you see primary on the left side. This is okay, otherwise when primary is on the right site the other node is the primary and we have to do the following steps there. On primary:

mount /dev/drbd0 /service
cp -Ra /var/lib/mysql/ /service/mysql

when we also have want apache:

mkdir /service/etc
cp -Ra /etc/apache2/ /service/etc/ 
ls /service/etc/apache2
apache2.conf  conf.d  envvars  httpd.conf  mods-available  mods-enabled  ports.conf  sites-available  sites-enabled
umount /dev/drbd0 /service

if you dont want apache dont forget to take it away from “config“ file no we have to edit:

nano /etc/apache2/apache2.conf
and correct the pathes for 
ls /service/etc/apache2
apache2.conf  conf.d  envvars  httpd.conf  mods-available  mods-enabled  ports.conf  sites-available  sites-enabled
aptitude install phpmyadmin
lisa:~# crm
crm(live)# configure
crm(live)configure# load replace /root/config
crm(live)configure# commit
crm(live)configure# quit
bye
lisa:~# crm status


============
Last updated: Tue Sep 22 18:33:02 2009
Stack: openais
Current DC: lisa - partition with quorum
Version: 1.0.4-2ec1d189f9c23093bf9239a980534b661baf782d
2 Nodes configured, 2 expected votes
2 Resources configured.
============

Online: [ bart lisa ]

Master/Slave Set: ms_drbd_mysql
        Masters: [ lisa ]
        Slaves: [ bart ]
Resource Group: mysql
    fs_mysql    (ocf::heartbeat:Filesystem):    Started lisa
    ip_mysql    (ocf::heartbeat:IPaddr2):       Started lisa
    mysqld      (lsb:mysql):    Started lisa
    apache      (lsb:apache2):  Started lisa</re>
Personal tools