3.3Apache Tomcat 5.5

I have not tried the bundled Apache Tomcat in the CentOS 5 Repository, I went ahead and downloaded it anyway from the tomcat.apache.org site:

cd /opt

wget http://apache.cyberuse.com/tomcat/tomcat-5/v5.5.27/bin/apache-tomcat-5.5.27.tar.gz

tar xzf apache-tomcat-5.5.27.tar.gz

mv apache-tomcat-5.5.27 tomcat

Start the Tomcat Daemon and send it to the background:

/opt/tomcat/bin/startup.sh &

Append it to the rc.local file to start at boot time:

echo “/opt/tomcat/bin/startup.sh &” >> /etc/rc.local

3.4Apache Ant 1.7

I have gone ahead and downloaded the source for apache ant too as I want to keep everything consistent and so it doesn`t break the CentOS installation.With this technique however, you can easily remove all the exported directories and delete the applications directory and install the stock rpmsupplied with CentOS later if you like.

cd /opt

wget http://apache.promopeddler.com/ant/binaries/apache-ant-1.7.1-bin.tar.gz

tar xzf apache-ant-1.7.1-bin.tar.gz

mv apache-ant-1.7.1 ant

echo “export ANT_HOME=/opt/ant” >> /etc/rc.local

export ANT_HOME=/opt/ant

4. Downloading and Installing OpenBravo 2.4

I am using OpenBravo 2.4 because this Howto was tested and declared working. However, there is a new release 2.5 which I have not tested and so you can try atyour won RISK.

cd /tmp

Download the installation binary from SourceForge:

wget http://surfnet.dl.sourceforge.net/sourceforge/openbravo/OpenbravoERP_2.40-linux-installer.bin

Make it executable:

chmod +x OpenbravoERP_2.40-linux-installer.bin

Run the installer:

./OpenbravoERP_2.40-linux-installer.bin

A text based installer will guide you through the installation. First press a few times ENTER to read the single parts of the license agreement. Type in yes at the end if you agree with it:

Do you accept this license? [y/n]: <– y

Before the installation begins you’ll be asked a few questions – answer them as follows:

Please specify the directory where Openbravo ERP will be installed

[/opt/OpenbravoERP]: <– ENTER

Please specify a directory for the Openbravo ERP attachments

[/opt/OpenbravoERP/AppsOpenbravo/attachments]: <– ENTER

Installation mode

Please select the installation mode you wish to perform

[1] Complete

The database and the application server in the same computer

[2] Distributed

The database and the application server in different computers

Please choose an option [1] : <– ENTER

Please select the installation type you wish to perform

[1] Standard

Installs the database and sets up the application server.

Recommended.

[2] Development

Installs the database and and sets up the application server

through a compilation process.

Recommended for developers.

Please choose an option [1] : <– ENTER

Please specify the directory where the JDK is located

[/opt/java]: <– ENTER

Please specify the location where the Ant executable is located

[/opt/ant/bin/ant]: <– ENTER

Please specify the directory where Tomcat is located.

In case of having Tomcat split into 2 directories, select the one containing the webapps directory

[/opt/tomcat]: <– ENTER

Please select a database

[1] PostgreSQL

[2] Oracle

Please choose an option [1] : <– ENTER

Please specify the directory where the binaries of the PostgreSQL installation are located (psql, pg_restore, vacuumdb)

[/usr/bin]: <– ENTER

Please enter the IP address of the PostgreSQL database

Database host [localhost]: <– ENTER

Please enter the port of the PostgreSQL database

Database port [5432]: <– ENTER

Enter the password for your “postgres” administrator user

Password : <– testpassword

Retype password : <– testpassword

Please enter the name of the PostgreSQL database

Database name [openbravo]: <– ENTER

Please enter a username for the Openbravo ERP PostgreSQL database

Username [tad]: <– admin

Please enter a password for the new database user

Password : <– adminpassword (a password of your choice)

Retype password : <– adminpassword

Enter a context name.

This is used in the URL to access Openbravo ERP:

http://<ip_address>:<port>/context_name

Context name [openbravo]: <– openbravoerp

Please select the preferred date and time formats

Date format

Date format

[1] DD MM YYYY

[2] MM DD YYYY

[3] YYYY MM DD

Please choose an option [1] : <– ENTER

Date separator

[1] -

[2] /

[3] .

[4] :

Please choose an option [2] : <– ENTER

Time format

[1] 12h

[2] 24h

Please choose an option [2] : <– ENTER

Time separator

[1] :

[2] .

Please choose an option [1] : <– ENTER

Should the installer populate the database with demo data?

[Y/n]: Y <– ENTER

Setup is now ready to begin installing Openbravo ERP on your computer.

Do you want to continue? [Y/n]: Y <– ENTER

The installation will take a few minutes, so please be patient:

Please wait while Setup installs Openbravo ERP on your computer.

Installing

0% ______________ 50% ______________ 100%

#########################################

—————————————————————————-

Setup has finished installing Openbravo ERP on your computer.

5. Testing the Waters

If everything up to this point is successful, then you have won!  You can access Openbravo at http://www.example.com:8080/openbravoerp or http://192.168.1.1:8080/openbravoerp. 

Log in with the username Openbravo and the password openbravo.

Note: I have decided not to post any screen shot of this as this has been tested and declared working. If you need more information, you can use the links provided below as reference.

6. Links

Openbravo: http://www.openbravo.com/

Centos: http://www.centos.org

 PostgreSQL 8.3: http://yum.pgsqlrpms.org

How To Install Openbravo ERP On CentOS 5.2

This howto describes how to set up Openbravo ERP (enterprise management system) on CentOS 5.2 using PostgreSQL 8.3. Openbravo is an open source ERP solution designed specifically for the SME (small to midsize firm). Developed in a web based environment, it includes many robust functionalities which are considered part of the extended ERP: procurement and warehouse management, project and service management, production management, and financial management.

This is a follow up of Falko`s Wonderful “How To Install Openbravo ERP On Ubuntu 8.10″.

I do not issue any guarantee that this will work for you!

 1. Preliminary Note

 This howto assumes you have freshly installed CentOS system along with the following.

 a) Hostname:- server1.example.com

 b) Server IP:- 192.168.1.1

 You must have root privileges to run most of the actions described in this Howto.

2. Setup DNS

yum install bind bind-utils

#nano /etc/named.conf

options
{ directory	"/var/named"; dump-file	"data/cache_dump.db"; statistics-file"data/named_stats.txt"; memstatistics-file"data/named_mem_stats.txt"; forwarders {ISP_DNS_IP;};
};
zone "example.com" IN {type master;file "forward.zone";
};

#nano /var/named/forward.zone

$TTL 3h
@	IN	SOA	server1	muffycompoqm.gmail.com. (	1	; Serial Number	15m	; Refresh Rate	30m	; Retry Interval	1h	; Expire Delay	2h )	; Negative Cache TTL
@	IN	NS	server1
@	IN	A	192.168.1.1
server1	IN	A	192.168.1.1
www	IN	CNAME	server1.example.com.
ftp	IN	CNAME server1.example.com.

#nano /etc/resolv.conf

search example.com
nameserver 127.0.0.1

#chkconfig –levels 35 named on

#service named start

3. Installing Openbravo Dependencies

3.1Postgresql 8.3

Exclude Postgresql from the CentOS base repository as OpenBravo uses Postgresql 8.3 which is not included in the base repository.

#nano /etc/yum.repos.d/CentOS-Base.repo

Add to the bottom of the file:

exclude=postgresql*

Download and install the RPMs from http://yum.pgsqlrpms.org:

wget http://yum.pgsqlrpms.org/reporpms/8.3/pgdg-centos-8.3-6.noarch.rpm

rpm -ivh pgdg-centos-8.3-6.noarch.rpm

yum install postgresql postgresql-server

Afterwards we have to set the PostgreSQL admin password:

sed -i ‘s/ident sameuser$/trust/’ /etc/postgresql/8.3/main/pg_hba.conf

service postgresql start

chkconfig –levels 35 postgresql on

Open a PostgreSQL shell and alter the postgres user role:

psql -U postgres

alter role postgres with password ‘testpassword’;\q

sed -i ‘s/trust$/md5/’ /etc/postgresql/8.3/main/pg_hba.conf

service postgresql reload

service postgresql restart

3.2 Sun Java JDK 1.6

You will have to download Java 1.6 JDK from http://java.sun.com/javase/downloads/index.jsp.

cp jdk-6u13-linux-i586.bin.bin /opt

cd /opt

sh jdk-6u13-linux-i586.bin.bin –unpack

mv jdk1-* java

echo “export JAVA_HOME=/opt/java” >> /etc/rc.local

export JAVA_HOME=/opt/java

3 Setting Up The GlusterFS Client

client1.example.com:

GlusterFS isn’t available as a package for CentOS 5.4, therefore we have to build it ourselves. First we install the prerequisites:

yum groupinstall ‘Development Tools’

yum groupinstall ‘Development Libraries’

yum install libibverbs-devel fuse-devel

Then we load the fuse kernel module…

modprobe fuse

… and create the file /etc/rc.modules with the following contents so that the fuse kernel module will be loaded automatically whenever the system boots:

vi /etc/rc.modules

modprobe fuse

Make the file executable:

chmod +x /etc/rc.modules

Then we download the GlusterFS 2.0.9 sources (please note that this is the same version that is installed on the server!) and build GlusterFS as follows:

cd /tmp
wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.9.tar.gz
tar xvfz glusterfs-2.0.9.tar.gz
cd glusterfs-2.0.9
./configure

At the end of the ./configure command, you should see something like this:

[...]
GlusterFS configure summary
===========================
FUSE client        : yes
Infiniband verbs   : yes
epoll IO multiplex : yes
Berkeley-DB        : yes
libglusterfsclient : yes
argp-standalone    : no

make && make install
ldconfig

Check the GlusterFS version afterwards (should be 2.0.9):

glusterfs –version

[root@client1 glusterfs-2.0.9]# glusterfs –version
glusterfs 2.0.9 built on Mar 1 2010 15:58:06
Repository revision: v2.0.9
Copyright (c) 2006-2009 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@client1 glusterfs-2.0.9]#

Then we create the following two directories:

mkdir /mnt/glusterfs
mkdir /etc/glusterfs

Next we create the file /etc/glusterfs/glusterfs.vol:

vi /etc/glusterfs/glusterfs.vol

volume remote1 type protocol/client option transport-type tcp option remote-host server1.example.com option remote-subvolume brick
end-volumevolume remote2 type protocol/client option transport-type tcp option remote-host server2.example.com option remote-subvolume brick
end-volumevolume replicate type cluster/replicate subvolumes remote1 remote2
end-volumevolume writebehind type performance/write-behind option window-size 1MB subvolumes replicate
end-volumevolume cache type performance/io-cache option cache-size 512MB subvolumes writebehind
end-volume

Make sure you use the correct server hostnames or IP addresses in the option remote-host lines!

That’s it! Now we can mount the GlusterFS filesystem to /mnt/glusterfs with one of the following two commands:

glusterfs -f /etc/glusterfs/glusterfs.vol /mnt/glusterfs

or

mount -t glusterfs /etc/glusterfs/glusterfs.vol /mnt/glusterfs

You should now see the new share in the outputs of…

mount

[root@client1 ~]# mount
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
glusterfs#/etc/glusterfs/glusterfs.vol on /mnt/glusterfs type fuse (rw,allow_other,default_permissions,max_read=131072)
[root@client1 ~]#

… and…

df -h

[root@client1 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       29G  2.2G   25G   9% /
/dev/sda1              99M   13M   82M  14% /boot
tmpfs                 187M     0  187M   0% /dev/shm
glusterfs#/etc/glusterfs/glusterfs.vol
                       28G  2.3G   25G   9% /mnt/glusterfs
[root@client1 ~]#

(server1.example.com and server2.example.com each have 28GB of space for the GlusterFS filesystem, but because the data is mirrored, the client doesn’t see 56GB (2 x 28GB), but only 28GB.)

Instead of mounting the GlusterFS share manually on the client, you could modify /etc/fstab so that the share gets mounted automatically when the client boots.

Open /etc/fstab and append the following line:

vi /etc/fstab

[...]
/etc/glusterfs/glusterfs.vol/mnt/glusterfsglusterfsdefaults00

To test if your modified /etc/fstab is working, reboot the client:

reboot

After the reboot, you should find the share in the outputs of…

df -h

… and…

mount

4 Testing

Now let’s create some test files on the GlusterFS share:

client1.example.com:

touch /mnt/glusterfs/test1
touch /mnt/glusterfs/test2

Now let’s check the /data/export directory on server1.example.com and server2.example.com. The test1 and test2 files should be present on each node:

server1.example.com/server2.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-22 16:50 test1
-rw-r–r– 1 root root 0 2010-02-22 16:50 test2
[root@server1 ~]#

Now we shut down server1.example.com and add/delete some files on the GlusterFS share on client1.example.com.

server1.example.com:

shutdown -h now

client1.example.com:

touch /mnt/glusterfs/test3
touch /mnt/glusterfs/test4
rm -f /mnt/glusterfs/test2

The changes should be visible in the /data/export directory on server2.example.com:

server2.example.com:

ls -l /data/export

[root@server2 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-22 16:50 test1
-rw-r–r– 1 root root 0 2010-02-22 16:53 test3
-rw-r–r– 1 root root 0 2010-02-22 16:53 test4
[root@server2 ~]#

Let’s boot server1.example.com again and take a look at the /data/export directory:

server1.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-22 16:50 test1
-rw-r–r– 1 root root 0 2010-02-22 16:50 test2
[root@server1 ~]#

As you see, server1.example.com hasn’t noticed the changes that happened while it was down. This is easy to fix, all we need to do is invoke a read command on the GlusterFS share on client1.example.com, e.g.:

client1.example.com:

ls -l /mnt/glusterfs/

[root@client1 ~]# ls -l /mnt/glusterfs/
total 0
-rw-r–r– 1 root root 0 2010-02-22 16:50 test1
-rw-r–r– 1 root root 0 2010-02-22 16:53 test3
-rw-r–r– 1 root root 0 2010-02-22 16:53 test4
[root@client1 ~]#

Now take a look at the /data/export directory on server1.example.com again, and you should see that the changes have been replicated to that node:

server1.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-22 16:50 test1
-rw-r–r– 1 root root 0 2010-02-22 16:53 test3
-rw-r–r– 1 root root 0 2010-02-22 16:53 test4
[root@server1 ~]#

5 Links

• GlusterFS: http://www.gluster.org/
• CentOS: http://www.centos.org/

High-Availability StorageWith GlusterFS On CentOS 5.4 – Automatic File Replication (Mirror) Across Two Storage Servers

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Follow me on Twitter
Last edited 02/22/2010

This tutorial shows how to set up a high-availability storage with two storage servers (CentOS 5.4) that use GlusterFS. Each storage server will be a mirror of the other storage server, and files will be replicated automatically across both storage servers. The client system (CentOS 5.4 as well) will be able to access the storage as if it was a local filesystem.GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

In this tutorial I use three systems, two servers and a client:

• server1.example.com: IP address 192.168.0.100 (server)
• server2.example.com: IP address 192.168.0.101 (server)
• client1.example.com: IP address 192.168.0.102 (client)

All threesystems should be able to resolve the other systems’ hostnames. If this cannot be done through DNS, you should edit the /etc/hosts file so that it contains the followinglines on all three systems:

vi /etc/hosts

[...]
192.168.0.100 server1.example.com server1
192.168.0.101 server2.example.com server2
192.168.0.102 client1.example.com client1
[...]

(It is also possible to use IP addresses instead of hostnames in the following setup. If you prefer to use IP addresses, you don’t have to care about whether the hostnames can be resolved or not.)

2 Setting Up The GlusterFS Servers

server1.example.com/server2.example.com:

GlusterFS isn’t available as a package for CentOS 5.4, therefore we have to build it ourselves. First we install the prerequisites:

yum groupinstall ‘Development Tools’

yum groupinstall ‘Development Libraries’

yum install libibverbs-devel fuse-devel

Then we download the latest GlusterFS release from http://www.gluster.org/download.php and build it as follows:

cd /tmp
wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.9.tar.gz
tar xvfz glusterfs-2.0.9.tar.gz
cd glusterfs-2.0.9
./configure

At the end of the ./configure command, you should see something like this:

[...]
GlusterFS configure summary
===========================
FUSE client        : yes
Infiniband verbs   : yes
epoll IO multiplex : yes
Berkeley-DB        : yes
libglusterfsclient : yes
argp-standalone    : no

[root@server1 glusterfs-2.0.9]#

make && make install
ldconfig

Check the GlusterFS version afterwards (should be 2.0.9):

glusterfs –version

[root@server1 glusterfs-2.0.9]# glusterfs –version
glusterfs 2.0.9 built on Mar 1 2010 15:34:50
Repository revision: v2.0.9
Copyright (c) 2006-2009 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@server1 glusterfs-2.0.9]#

Next we create a few directories:

mkdir /data/
mkdir /data/export
mkdir /data/export-ns
mkdir /etc/glusterfs

Now we create the GlusterFS server configuration file /etc/glusterfs/glusterfsd.vol which defines which directory will be exported (/data/export) and what client is allowed to connect (192.168.0.102 = client1.example.com):

vi /etc/glusterfs/glusterfsd.vol

volume posix type storage/posix option directory /data/export
end-volumevolume locks type features/locks subvolumes posix
end-volumevolume brick type performance/io-threads option thread-count 8 subvolumes locks
end-volumevolume server type protocol/server option transport-type tcp option auth.addr.brick.allow 192.168.0.102 subvolumes brick
end-volume

Please note that it is possible to use wildcards for the IP addresses (like 192.168.*) and that you can specify multiple IP addresses separated by comma (e.g. 192.168.0.102,192.168.0.103).

Afterwards we create the following symlink…

ln -s /usr/local/sbin/glusterfsd /sbin/glusterfsd

… and then the system startup links for the GlusterFS server and start it:

chkconfig –levels 35 glusterfsd on
/etc/init.d/glusterfsd start

Installation Of BIND As A Secondary (Slave) DNS ServerOn CentOS

After we have installed BIND as a master DNS server (NS1) (as explained in my recent post), we can now try to set up a secondary DNS server (NS2) with BIND on CentOS. NS2 acts as a backup if there are problems with NS1.

Make sure you’ve successfully set up NS1, as described in my previous post!

NS1 with IP 192.168.0.1
NS2 with IP 192.168.0.2
Our domain: yourdomain.com

Now we can try setting up NS2.

1.  Check your Bind package

[root@server ~]# rpm -qa bind*

bind-libs-9.2.4-2

bind-utils-9.2.4-2

bind-9.2.4-2

2. Setting file /etc/resolv.conf

[root@server ~]# nano
/etc/resolv.conf

nameserver 192.168.0.1

3. Setting file /etc/named.conf

[root@server ~]# nano
/etc/named.conf

//
// named.conf for Red Hat caching-nameserver
//options {
directory "/var/named";
dump-file "/var/named/data/cache_dump.db";
statistics-file "/var/named/data/named_stats.txt";/*
* If there is a firewall between you and nameservers you want
* to talk to, you might need to uncomment the query-source
* directive below. Previous versions of BIND always asked
* questions using port 53, but BIND 8.1 uses an unprivileged
* port by default.
*/// query-source address * port 53;
allow-transfer {208.99.198.184/32;};
};//
// a caching only nameserver config
//controls {
inet 127.0.0.1 allow { localhost; } keys { rndckey; };
};zone "localhost" IN {
type master;
file "localhost.zone";
allow-update { none; };
};zone "yourdomain.com" IN {
type slave;
file "/var/named/yourdomain.com.zone";
// allow-update { none; };
allow-transfer { 192.168.0.1/32; };
masters { 192.168.0.1; };
};zone "0.168.192.in-addr.arpa" IN {
type slave;
file "/var/named/0.168.192.rev";
// allow-update { none; };
allow-transfer { 192.168.0.1/32; };
masters { 192.168.0.1; };
};include "/etc/rndc.key";

4. Change permission of the directory /var/named

[root@server ~]# chmod 777 -Rvf
/var/named/

mode of `/var/named/’ changed to
0777 (rwxrwxrwx)

mode of `/var/named/named.zero’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/localhost.zone’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/data’ changed
to 0777 (rwxrwxrwx)

mode of `/var/named/named.local’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/named.ca’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/named.ip6.local’ changed to 0777 (rwxrwxrwx)

mode of
`/var/named/localdomain.zone’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/named.broadcast’ changed to 0777 (rwxrwxrwx)

mode of `/var/named/slaves’ changed to 0777 (rwxrwxrwx)

5. The files /var/named/yourdomain.com and
/var/named/0.168.192.rev will automatically be copied to NS2.

6. Running service named

[root@server ~]# service named
restart

Stopping named: [ OK ]

Starting named: [ OK ]

7. And check in log file what’s the matter???

[root@server ~]# tail
/var/log/messages

Aug 3 04:25:42 server named[9362]:
listening on IPv4 interface venet0:0, 192.168.0.2#53
Aug 3
04:25:42 server named[9362]: command channel listening on
127.0.0.1#953
Aug 3 04:25:42 server named[9362]: zone
localhost/IN: loaded serial 42
Aug 3 04:25:42 server named[9362]:
running
Aug 3 04:25:42 server named[9362]: zone yourdomain.com/IN:
transferred serial 100
Aug 3 04:25:42 server named[9362]: transfer
of ‘yourdomain.com/IN’ from 192.168.0.1#53: end of transfer
Aug
3 04:25:42 server named[9362]: zone yourdomain.com/IN: sending
notifies (serial 100)
Aug 3 04:25:43 server named[9362]: zone
0.168.192.in-addr.arpa/IN: transferred serial 100
Aug 3 04:25:43
server named[9362]: transfer of ‘0.168.192.in-addr.arpa/IN’ from
192.168.0.1#53: end of transfer
Aug 3 04:25:43 server named[9362]:
zone 0.168.192.in-addr.arpa/IN: sending notifies (serial
100)

Looking at this log, you can see
that the yourdomain.com zone gets transferred. Actually this
file is copied to NS2 so, if NS1 is dead or has a problem, NS2 has a backup
configuration.

8. Result using nslookup

[root@server ~]# nslookup
yourdomain.com

Server: 192.168.0.1

Address: 192.168.0.1#53

Name: yourdomain.com

Address: 192.168.0.1

answered from nslookup used server
from NS1 with IP 192.168.0.1

Now we can try to deactivate NS1 to see if name resolution is still working.

9. First adding nameserver 192.168.0.2

[root@server ~]# cat
/etc/resolv.conf

nameserver 192.168.0.1

nameserver 192.168.0.2

This domain is using NS2 because
NS1 is not active. We don’t need to change any files on NS2 because all zone files are transferred from NS1 to NS2.

10. Trying a DNS lookup while NS1 is down

[root@server ~]# nslookup
yourdomain.com

Server: 192.168.0.2

Address: 192.168.0.2#53

Name: yourdomain.com

Address: 192.168.0.1

Now if there’s any problem with NS1 you can rest calm because NS2 acts as a backup.

3 Setting Up The GlusterFS Client

client1.example.com:

GlusterFS isn’t available as a package for CentOS 5.4, therefore we have to build it ourselves. First we install the prerequisites:

yum groupinstall ‘Development Tools’

yum groupinstall ‘Development Libraries’

yum install libibverbs-devel fuse-devel

Then we load the fuse kernel module…

modprobe fuse

… and create the file /etc/rc.modules with the following contents so that the fuse kernel module will be loaded automatically whenever the system boots:

vi /etc/rc.modules

modprobe fuse

Make the file executable:

chmod +x /etc/rc.modules

Then we download the GlusterFS 2.0.9 sources (please note that this is the same version that is installed on the server!) and build GlusterFS as follows:

cd /tmp
wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.9.tar.gz
tar xvfz glusterfs-2.0.9.tar.gz
cd glusterfs-2.0.9
./configure

At the end of the ./configure command, you should see something like this:

[...]
GlusterFS configure summary
===========================
FUSE client        : yes
Infiniband verbs   : yes
epoll IO multiplex : yes
Berkeley-DB        : yes
libglusterfsclient : yes
argp-standalone    : no

make && make install
ldconfig

Check the GlusterFS version afterwards (should be 2.0.9):

glusterfs –version

[root@client1 glusterfs-2.0.9]# glusterfs –version
glusterfs 2.0.9 built on Mar 1 2010 15:58:06
Repository revision: v2.0.9
Copyright (c) 2006-2009 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@client1 glusterfs-2.0.9]#

Then we create the following two directories:

mkdir /mnt/glusterfs
mkdir /etc/glusterfs

Next we create the file /etc/glusterfs/glusterfs.vol:

vi /etc/glusterfs/glusterfs.vol

volume remote1 type protocol/client option transport-type tcp option remote-host server1.example.com option remote-subvolume brick
end-volumevolume remote2 type protocol/client option transport-type tcp option remote-host server2.example.com option remote-subvolume brick
end-volumevolume remote3 type protocol/client option transport-type tcp option remote-host server3.example.com option remote-subvolume brick
end-volumevolume remote4 type protocol/client option transport-type tcp option remote-host server4.example.com option remote-subvolume brick
end-volumevolume replicate1 type cluster/replicate subvolumes remote1 remote2
end-volumevolume replicate2 type cluster/replicate subvolumes remote3 remote4
end-volumevolume distribute type cluster/distribute subvolumes replicate1 replicate2
end-volumevolume writebehind type performance/write-behind option window-size 1MB subvolumes distribute
end-volumevolume cache type performance/io-cache option cache-size 512MB subvolumes writebehind
end-volume

Make sure you use the correct server hostnames or IP addresses in the option remote-host lines!

That’s it! Now we can mount the GlusterFS filesystem to /mnt/glusterfs with one of the following two commands:

glusterfs -f /etc/glusterfs/glusterfs.vol /mnt/glusterfs

or

mount -t glusterfs /etc/glusterfs/glusterfs.vol /mnt/glusterfs

You should now see the new share in the outputs of…

mount

[root@client1 ~]# mount
/dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw)
proc on /proc type proc (rw)
sysfs on /sys type sysfs (rw)
devpts on /dev/pts type devpts (rw,gid=5,mode=620)
/dev/sda1 on /boot type ext3 (rw)
tmpfs on /dev/shm type tmpfs (rw)
none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
glusterfs#/etc/glusterfs/glusterfs.vol on /mnt/glusterfs type fuse (rw,allow_other,default_permissions,max_read=131072)
[root@client1 ~]#

… and…

df -h

[root@client1 ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                       29G  2.2G   25G   9% /
/dev/sda1              99M   13M   82M  14% /boot
tmpfs                 187M     0  187M   0% /dev/shm
glusterfs#/etc/glusterfs/glusterfs.vol
                       56G  2.3G   54G   4% /mnt/glusterfs
[root@client1 ~]#

(The size of the distributed storage is calculated by replication1 + replication2, where both replication volumes are as big as the smallest brick.)

Instead of mounting the GlusterFS share manually on the client, you could modify /etc/fstab so that the share gets mounted automatically when the client boots.

Open /etc/fstab and append the following line:

vi /etc/fstab

[...]
/etc/glusterfs/glusterfs.vol/mnt/glusterfsglusterfsdefaults00

To test if your modified /etc/fstab is working, reboot the client:

reboot

After the reboot, you should find the share in the outputs of…

df -h

… and…

mount

4 Testing

Now let’s create some test files on the GlusterFS share:

client1.example.com:

touch /mnt/glusterfs/test1
touch /mnt/glusterfs/test2
touch /mnt/glusterfs/test3
touch /mnt/glusterfs/test4
touch /mnt/glusterfs/test5
touch /mnt/glusterfs/test6

Now let’s check the /data/export directory on server1.example.com, server2.example.com, server3.example.com, and server4.example.com. You will notice that replication1 as well as replication2 hold only a part of the files/directories that make up the GlusterFS share on the client, but the nodes that make up replication1 (server1 and server2) or replication2 (server3 and server4) contain the same files (mirroring):

server1.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
-rw-r–r– 1 root root 0 2010-02-23 15:41 test5
[root@server1 ~]#

server2.example.com:

ls -l /data/export

[root@server2 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
-rw-r–r– 1 root root 0 2010-02-23 15:41 test5
[root@server2 ~]#

server3.example.com:

ls -l /data/export

[root@server3 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
-rw-r–r– 1 root root 0 2010-02-23 15:41 test6
[root@server3 ~]#

server4.example.com:

ls -l /data/export

[root@server4 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
-rw-r–r– 1 root root 0 2010-02-23 15:41 test6
[root@server4 ~]#

Now we shut down server1.example.com and server4.example.com and add/delete some files on the GlusterFS share on client1.example.com.

server1.example.com/server4.example.com:

shutdown -h now

client1.example.com:

rm -f /mnt/glusterfs/test5
rm -f /mnt/glusterfs/test6

The changes should be visible in the /data/export directory on server2.example.com and server3.example.com:

server2.example.com:

ls -l /data/export

[root@server2 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
[root@server2 ~]#

server3.example.com:

ls -l /data/export

[root@server3 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
[root@server3 ~]#

Let’s boot server1.example.com and server4.example.com again and take a look at the /data/export directory:

server1.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
-rw-r–r– 1 root root 0 2010-02-23 15:41 test5
[root@server1 ~]#

server4.example.com:

ls -l /data/export

[root@server4 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
-rw-r–r– 1 root root 0 2010-02-23 15:41 test6
[root@server4 ~]#

As you see, server1.example.com and server4.example.com haven’t noticed the changes that happened while they were down. This is easy to fix, all we need to do is invoke a read command on the GlusterFS share on client1.example.com, e.g.:

client1.example.com:

ls -l /mnt/glusterfs/

[root@client1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
[root@client1 ~]#

Now take a look at the /data/export directory on server1.example.com and server4.example.com again, and you should see that the changes have been replicated to these nodes:

server1.example.com:

ls -l /data/export

[root@server1 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test1
-rw-r–r– 1 root root 0 2010-02-23 15:41 test2
-rw-r–r– 1 root root 0 2010-02-23 15:41 test4
[root@server1 ~]#

server4.example.com:

ls -l /data/export

[root@server4 ~]# ls -l /data/export
total 0
-rw-r–r– 1 root root 0 2010-02-23 15:41 test3
[root@server4 ~]#

5 Links

• GlusterFS: http://www.gluster.org/
• CentOS: http://www.centos.org/

Distributed Replicated Storage Across Four Storage Nodes With GlusterFS On CentOS 5.4

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Follow me on Twitter
Last edited 03/01/2010

This tutorial shows how to combine four single storage servers (running CentOS 5.4) to a distributed replicated storage with GlusterFS. Nodes 1 and 2 (replication1) as well as 3 and 4 (replication2) will mirror each other, and replication1 and replication2 will be combined to one larger storage server (distribution). Basically, this is RAID10 over network. If you lose one server from replication1 and one from replication2, the distributed volume continues to work. The client system (CentOS 5.4 as well) will be able to access the storage as if it was a local filesystem.GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

In this tutorial I use five systems, four servers and a client:

• server1.example.com: IP address 192.168.0.100 (server)
• server2.example.com: IP address 192.168.0.101 (server)
• server3.example.com: IP address 192.168.0.102 (server)
• server4.example.com: IP address 192.168.0.103 (server)
• client1.example.com: IP address 192.168.0.104 (client)

All five systems should be able to resolve the other systems’ hostnames. If this cannot be done through DNS, you should edit the /etc/hosts file so that it contains the following lines on all five systems:

vi /etc/hosts

[...]
192.168.0.100 server1.example.com server1
192.168.0.101 server2.example.com server2
192.168.0.102 server3.example.com server3
192.168.0.103 server4.example.com server4
192.168.0.104 client1.example.com client1
[...]

(It is also possible to use IP addresses instead of hostnames in the following setup. If you prefer to use IP addresses, you don’t have to care about whether the hostnames can be resolved or not.)

2 Setting Up The GlusterFS Servers

server1.example.com/server2.example.com/server3.example.com/server4.example.com:

GlusterFS isn’t available as a package for CentOS 5.4, therefore we have to build it ourselves. First we install the prerequisites:

yum groupinstall ‘Development Tools’

yum groupinstall ‘Development Libraries’

yum install libibverbs-devel fuse-devel

Then we download the latest GlusterFS release from http://www.gluster.org/download.php and build it as follows:

cd /tmp
wget http://ftp.gluster.com/pub/gluster/glusterfs/2.0/LATEST/glusterfs-2.0.9.tar.gz
tar xvfz glusterfs-2.0.9.tar.gz
cd glusterfs-2.0.9
./configure

At the end of the ./configure command, you should see something like this:

[...]
GlusterFS configure summary
===========================
FUSE client        : yes
Infiniband verbs   : yes
epoll IO multiplex : yes
Berkeley-DB        : yes
libglusterfsclient : yes
argp-standalone    : no

[root@server1 glusterfs-2.0.9]#

make && make install
ldconfig

Check the GlusterFS version afterwards (should be 2.0.9):

glusterfs –version

[root@server1 glusterfs-2.0.9]# glusterfs –version
glusterfs 2.0.9 built on Mar 1 2010 15:34:50
Repository revision: v2.0.9
Copyright (c) 2006-2009 Gluster Inc. <http://www.gluster.com>
GlusterFS comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GlusterFS under the terms of the GNU General Public License.
[root@server1 glusterfs-2.0.9]#

Next we create a few directories:

mkdir /data/
mkdir /data/export
mkdir /data/export-ns
mkdir /etc/glusterfs

Now we create the GlusterFS server configuration file /etc/glusterfs/glusterfsd.vol which defines which directory will be exported (/data/export) and what client is allowed to connect (192.168.0.104 = client1.example.com):

vi /etc/glusterfs/glusterfsd.vol

volume posix type storage/posix option directory /data/export
end-volumevolume locks type features/locks subvolumes posix
end-volumevolume brick type performance/io-threads option thread-count 8 subvolumes locks
end-volumevolume server type protocol/server option transport-type tcp option auth.addr.brick.allow 192.168.0.104 subvolumes brick
end-volume

Please note that it is possible to use wildcards for the IP addresses (like 192.168.*) and that you can specify multiple IP addresses separated by comma (e.g. 192.168.0.104,192.168.0.105).

Afterwards we create the following symlink…

ln -s /usr/local/sbin/glusterfsd /sbin/glusterfsd

… and then the system startup links for the GlusterFS server and start it:

chkconfig –levels 35 glusterfsd on
/etc/init.d/glusterfsd start

Installing PowerDNS With MySQL On CentOS

What is PowerDNS?

PowerDNS is a MySQL-based DNS server, written in C++ and licensed under the GPL. PowerDNS can be managed through a web interface (PowerAdmin). This guide shows how to install it on CentOS.

1. Installing MySQL

[root@server ~]# yum -y install mysql mysql-server

2. Create system startup links for MySQL

[root@server ~]# chkconfig –levels 235 mysqld on

[root@server ~]# service mysqld start

3. Check if MySQL is running

[root@server ~]# netstat -tap | grep mysql

tcp        0      0 *:mysql                 *:*     LISTEN   28179/mysqld 

4. Set password for user root

[root@server ~]# mysqladmin -u root password password123

5. Install PowerDNS

[root@server ~]# yum -y install pdns pdns-backend-mysql

6. Setting database

[root@server ~]# mysql -u root -p

mysql> CREATE DATABASE powerdns;

mysql> user powerdns;

mysql> CREATE TABLE domains (
-> id INT auto_increment,
-> name VARCHAR(255) NOT NULL,
-> master VARCHAR(128) DEFAULT NULL,
-> last_check INT DEFAULT NULL,
-> type VARCHAR(6) NOT NULL,
-> notified_serial INT DEFAULT NULL,
-> account VARCHAR(40) DEFAULT NULL,
-> primary key (id)
-> );

mysql> CREATE UNIQUE INDEX name_index ON domains(name);

mysql> CREATE TABLE records (
-> id INT auto_increment,
-> domain_id INT DEFAULT NULL,
-> name VARCHAR(255) DEFAULT NULL,
-> type VARCHAR(6) DEFAULT NULL,
-> content VARCHAR(255) DEFAULT NULL,
-> ttl INT DEFAULT NULL,
-> prio INT DEFAULT NULL,
-> change_date INT DEFAULT NULL,
-> primary key(id)
-> );

mysql> CREATE INDEX rec_name_index ON records(name);

mysql> CREATE INDEX nametype_index ON records(name,type);

mysql> CREATE INDEX domain_id ON records(domain_id);

mysql> CREATE TABLE supermasters (
-> ip VARCHAR(25) NOT NULL,
-> nameserver VARCHAR(255) NOT NULL,
-> account VARCHAR(40) DEFAULT NULL
-> );

mysql> quit;

[root@server ~]# nano /etc/pdns/pdns.conf

#################################
# launch Which backends to launch and order to query them in
#
# launch=launch=gmysqlgmysql-host=192.200.200.1gmysql-user=power_admingmysql-password=password123gmysql-dbname=powerdns#################################

7. Create the system startup links for PowerDNS

[root@server ~]# chkconfig –levels 235 pdns on

[root@server ~]# service pdns start

8. Preparing the system for PowerAdmin installation

[root@server ~]# yum -y install httpd php php-devel php-gd php-imap php-ldap php-mysql php-odbc php-pear php-xml php-xmlrpc php-mbstring php-mcrypt php-mhash gettext

9. Create system startup links for apache and start it

[root@server ~]# chkconfig –levels 235 httpd on

[root@server ~]# service httpd start

10. Install following two PEAR packages

yum -y install php-pear-DB php-pear-MDB2-Driver-mysql

11. Download PowerAdmin

[root@server ~]# wget https://www.poweradmin.org/download/poweradmin-2.1.2.tgz

[root@server ~]# tar zxvf poweradmin-2.1.2.tgz -C /var/www/html/

[root@server ~]# mv poweradmin-2.1.2 poweradmin

[root@server ~]# mv /var/www/html/poweradmin/inc/config.inc.php

[root@server ~]# chown -R apache:apache /var/www/html/poweradmin/

VBoxHeadless – Running Virtual Machines With VirtualBox 3.1.x On A Headless CentOS 5.4 Server

Version 1.0
Author: Falko Timme <ft [at] falkotimme [dot] com>
Follow me on Twitter
Last edited 02/03/2010

This guide explains how you can run virtual machines with SunVirtualBox 3.1.xon a headless CentOS 5.4 server. Normally you use the VirtualBox GUI to manage your virtual machines, but a server does not have a desktop environment. Fortunately, VirtualBox comes with a tool called VBoxHeadless that allows you to connect to the virtual machines over a remote desktop connection, so there’s no need for the VirtualBox GUI.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

I have tested this on a CentOS 5.4 server (host system) with the IP address 192.168.0.100 where I’m logged in as a normal user (user name admin in this example) instead of as root.

If you only have a root account, but no normal user account, create one as follows (user admin, group admin)…

# groupadd admin
# useradd -d /home/admin -m -g admin -s /bin/bash admin

… create a password for the new user…

# passwd admin

… and log in as that user.

2 Installing VirtualBox

To install VirtualBox 3.1.x on our CentOS 5.4 server, we need root privileges, therefore we run

$ su

Next download and register Sun’s public rpm key:

# wget -q http://download.virtualbox.org/virtualbox/debian/sun_vbox.asc
# rpm –import sun_vbox.asc
# rm -f sun_vbox.asc

Now we enable the VirtualBox OpenSUSE repository on our system:

# cd /etc/yum.repos.d/
# wget http://download.virtualbox.org/virtualbox/rpm/rhel/virtualbox.repo

We can now simply install VirtualBox 3.1.x as follows:

# yum install VirtualBox-3.1

Now we must add the user that will run VirtualBox (admin in this example) to the vboxusers group:

# /usr/sbin/usermod -G vboxusers admin

VirtualBox is now installed and ready to be used.

Type

# exit

to leave the root account and become a normal user (admin) again.

3 Using VirtualBox On The Command Line

3.1 Creating A VM

To create a VM on the command line, we can use the VBoxManage command. See

$ VBoxManage –help

for a list of available switches and (highly recommended!) take a look at http://www.virtualbox.org/manual/UserManual.html#vboxmanage.

I will now create an Ubuntu 9.10 Server VM with 256MB memory and a 10GB hard drive from the Ubuntu 9.10 Server iso image (which I have stored in /home/ubuntu-9.10-server-amd64.iso):

$ VBoxManage createvm –name “Ubuntu 9.10 Server” –register
$ VBoxManage modifyvm “Ubuntu 9.10 Server” –memory 256 –acpi on –boot1 dvd –nic1 bridged –bridgeadapter1 eth0
$ VBoxManage createhd –filename Ubuntu_9_10_Server.vdi –size 10000 –register
$ VBoxManage storagectl “Ubuntu 9.10 Server” –name “IDE Controller” –add ide
$ VBoxManage storageattach “Ubuntu 9.10 Server” –storagectl “IDE Controller” –port 0 –device 0 –type hdd –medium Ubuntu_9_10_Server.vdi
$ VBoxManage storageattach “Ubuntu 9.10 Server” –storagectl “IDE Controller” –port 1 –device 0 –type dvddrive –medium /home/ubuntu-9.10-server-amd64.iso

3.2 Importing An Existing VM

Let’s assume you have a VM called examplevm that you want to reuse on this host. On the old host, you should have a directory Machines/examplevm in the VirtualBox directory; Machines/examplevm should contain the examplevm.xml file. Copy the examplevm directory (including the examplevm.xml file) to your new Machines directory (if your user name is admin, this is /home/admin/.VirtualBox/Machines – the result should be /home/admin/.VirtualBox/Machines/examplevm/examplevm.xml).

In addition to that copy the examplevm.vdi file from the old VDI directory to the new one (e.g. /home/admin/.VirtualBox/VDI/examplevm.vdi).

Afterwards, you must register the imported VM:

$ VBoxManage registervm Machines/examplevm/examplevm.xml

3.3 Starting A VM With VBoxHeadless

Regardless of if you create a new VM or import and old one, you can start it with the command:

$ VBoxHeadless –startvm “Ubuntu 9.10 Server”

(Replace Ubuntu 9.10 Server with the name of your VM.)

VBoxHeadless will start the VM and a VRDP (VirtualBox Remote Desktop Protocol) server which allows you to see the VM’s output remotely on another machine.

To stop a VM, run

$ VBoxManage controlvm “Ubuntu 9.10 Server” poweroff

To pause a VM, run

$ VBoxManage controlvm “Ubuntu 9.10 Server” pause

To reset a VM, run

$ VBoxManage controlvm “Ubuntu 9.10 Server” reset

To learn more about VBoxHeadless, take a look at

$ VBoxHeadless –help

and at http://www.virtualbox.org/manual/UserManual.html.