First you need to set SELinux in permissive mode (if you have enabled it) and configure the firewall to let other systems to connect to port 80/443 (HTTP and HTTPs) and 389 (LDAP server port) using the commandline tool

# system-config-securitylevel-tui

Now we need to get some more RPM repos to work:

//First the CentOS testing repo
# cd /etc/yum.repos.d/
# wget http://dev.centos.org/centos/5/CentOS-Testing.repo
//Then the RPMForge repo
# rpm -Uhv http://apt.sw.be/redhat/el5/en/x86_64/rpmforge/RPMS//rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm
//And last the GOsa RPM repo
# cat >> GOsa.repo << EOF
> [GOsa-Repository]
> name=GOsa Repository
> baseurl=ftp://oss.gonicus.de/pub/gosa/redhat
> enabled=0
> gpgcheck=0
> EOF

As we want the system as stable as possible without many packages from externarl repositories please verify that the files CentOS-Testing.repo and rpmforge.repo both contain the line ‘enabled=0‘. Now let’s check the new repositories for new packages to install and install them:

# yum –enablerepo=rpmforge,GOsa-Repository,c5-testing check-update
//Install LDAP
# yum install openldap openldap-servers
//Install PHP 5.2 from CentOS Testing
# yum –enablerepo=c5-testing install php-common php-imap php-snmp php-mysql php-mbstring php-pdo
//Install perl-Crypt-SmbHash from RPMForge
# yum –enablerepo=rpmforge install perl-Crypt-SmbHash
//Install GOsa RPMs
# yum –enablerepo=GOsa-Repository install gosa-help-en.noarch gosa-plugin-addressbook.noarch gosa-plugin-ldapmanager.noarch gosa-plugin-mail.noarch gosa-plugin-rolemanagement.noarch gosa-plugin-systems.noarch gosa-schema.noarch gosa-plugin-goto

Now we need to be sure that Apache HTTPD and LDAP servers start at boot:

# chkconfig httpd on
# chkconfig ldap on

At this point, before configuring GOsa, you need to add specific GOsa schemas to your ldap using as reference a part of the beginning of my own /etc/openldap/slapd.conf

include         /etc/openldap/schema/core.schema
include         /etc/openldap/schema/cosine.schema
include         /etc/openldap/schema/inetorgperson.schema
include         /etc/openldap/schema/gosa/rfc2307bis.schema
include         /etc/openldap/schema/gosa/gofax.schema
include         /etc/openldap/schema/gosa/gofon.schema
include         /etc/openldap/schema/gosa/samba.schema
include         /etc/openldap/schema/gosa/gosystem.schema
include         /etc/openldap/schema/gosa/goto.schema
include         /etc/openldap/schema/gosa/samba3.schema
include         /etc/openldap/schema/gosa/gosa-samba3.schema
include         /etc/openldap/schema/gosa/goserver.schema
include         /etc/openldap/schema/gosa/goto-mime.schema
include         /etc/openldap/schema/gosa/trust.schema

Restart your openldap and finally we can connect to GOsa web interface and configure it pointing your browser at

http://<hostname>/gosa/

Now you should have a fully functional GOsa install on your CentOS5: please let me know if you found error in this tutorial or even if you found it useful.

The smartest solution I found was to use stunnel: maybe an overkill software for this simple task but it is

1. well known and opensource;
2. stable;
3. works as a windows service.

My own problem was to forward SMTP traffic from port 65025 to the well known port 25: this way if I telnet to port 65025 I can speak directly with the SMTP server listening on port 25.

The first thing was to download stunnel for windows and install it.

Now all the magic is to write the appropriate stunnel.conf file that, in my case, was something like this:

; Certificate/key is needed in server mode and optional in client mode
; The default certificate is provided only for testing and should not
; be used in a production environment
cert = stunnel.pem
; Some performance tunings
socket = l:TCP_NODELAY=1
socket = r:TCP_NODELAY=1
[in65025smtp]
accept = 10.145.2.88:65025
connect = 10.145.2.88:65024
protocol = smtp
client = yes
[out25smtp]
accept = 10.145.2.88:65024
connect = 10.145.2.88:25
protocol = smtp

Looking at the stunnel.conf file provided you can see the trick: stunnel accept SMTP connections on port 65025 and encrypts them forwarding the traffic to port 65024; then it gets encrypted SMTP traffic from port 65024 and forwards it decrypted to port 25.

Last but not least is to register stunnel as service: in Windows this is as easy as 1, 2, 3

Please remember also to start the service

I hope this is clear… if you find something wrong here please let me know and I will correct it!

The first thing to do is to check if you have installed the prerequisites packages:

# pkginfo -i SUNWbtool SUNWarc SUNWhea SUNWlibmr \
SUNWlibm SUNWlibms SUNWsprot SUNWtoo SUNWi1of \
SUNWi1cs SUNWi15cs SUNWxwfnt SUNWpoolr SUNWpool \
SUNWuiu8

If you see any error here you must install the missing packages: if you did the “full installation” you should have all packages already installed.

Now its time to create user, groups, directories and project: as root type

//create user and groups
# groupadd oinstall
# groupadd dba
# useradd -g oinstall -G dba -m -d /export/home/oracle -s /usr/bin/bash oracle
//create the project (this is optional)
# projadd -U oracle oracle
//create the installation dir and give the right permissions
# mkdir /opt/oracle
# chown -R oracle:oinstall /opt/oracle

OK… as root we have temporarily finished!

Now log in with the oracle user and download the Oracle Client 10g for Solaris10 from Oracle website: once there you need to select the right architecture (Solaris exists for SPARC and x86 both 32 and 64 bit) and get the right archive for the Oracle client installation. In my own situation (Solaris10 on a x86 64bit) I downloaded the file called 10201_client_solx86_64.zip and I typed:

# unzip 10201_client_solx86_64.zip
# cd client/
# ./runInstaller

As you can see (click on the image to see a bigger picture) I used /opt/oracle/oraInventory and I leaved the group oinstall as the default group.

As ORACLE_HOME I used /opt/oracle/product/10.2.0/client_1.

Just before the installation finishes it prompts to you to execute two more commands as root: in my own installation I run

//execute the following commands as root
# /opt/oracle/oraInventory/orainstRoot.sh
# /opt/oracle/product/10.2.0/client_1/root.sh

but, as you may guess, your path may be different from mine.

Now, if you want to use the just installed oracle binaries, you need to change the .profile of the user adding at the end:

ORACLE_BASE=/opt/oracle
ORACLE_HOME=/opt/oracle/product/10.2.0/client_1
PATH=$PATH:/opt/oracle/product/10.2.0/client_1/bin/
export ORACLE_BASE
export ORACLE_HOME
export PATH

I hope this tutorial can help you… if you find errors please report them to me and I will correct as soon as possible.

What is a MySQL cluster?

Let’s start explaining the architecture of a MySQL cluster with an image taken from dev.mysql.com:

As you may see the MySQL cluster is an aggregation of many components:

• one management server;
• many MySQL daemons that acts as “frontend”;
• many data nodes that store the real data.

This tutorial will guide you in the creation of a cluster with:

• one management node;
• two MySQL daemons;
• two data nodes.

Obviously you can expand this configuration simply adding the components you need. As stated at the beginning of this tutorial you can create all this setup on a single server (well you need 3 IPs on the server) or, and that would be very easy, you can split the MySQL cluster components on many servers.

On the linux machine, as root, you have to run the following commands:

//create user and groups
# groupadd oinstall
# groupadd dba
# useradd -g oinstall -G dba oracle
# passwd oracle

//prepare the filesystem
# mkdir /opt/oracle
# chown -R oracle:oinstall /opt/oracle

//install some needed packages
# yum install libXp gcc make setarch libaio glibc-devel

//change /etc/redhat-release as RHEL5 is not a supported platform
# cp /etc/redhat-release /etc/redhat-release.5
# echo redhat-4 > /etc/redhat-release

OK… as root we have now finished!

Now log in with the oracle user and download the Oracle Client 10g 64bit from Oracle website: once there get the file called 10201_client_linux_x86_64.cpio.gz. Open the cpio oracle client archive and run the client installation program:

# gunzip 10201_client_linux_x86_64.cpio.gz
# cpio -idmv < 10201_client_linux_x86_64.cpio
# cd client
# ./runInstaller

I pointed the oraInventory directory to /opt/oracle in the first screen; in the second one I choose to install the Oracle 10g Client in /opt/oracle/product/10.2.0/client_1/. Just before the installation finishes it prompts to you to execute two more commands as root: in my own installation I run

//execute the following commands as root
# /opt/oracle/orainstRoot.sh
# /opt/oracle/product/10.2.0/client_1/root.sh

but, as you may guess, your path may be different from mine.

Now the final step: we have to restore the /etc/redhat-release file we changed before:

# mv /etc/redhat-release.5 /etc/redhat-release

I hope this tutorial can help you… if you find errors please report them to me and I will correct as soon as possible.

On the linux machine, as root, you have to run the following commands:

//create user and groups
# groupadd oinstall
# groupadd dba
# useradd -g oinstall -G dba oracle
# passwd oracle

//prepare the filesystem
# mkdir /opt/oracle
# chown -R oracle:oinstall /opt/oracle

//install some needed packages
# yum install libXp gcc make setarch libaio glibc-devel

//change /etc/redhat-release as RHEL5 is not a supported platform
# cp /etc/redhat-release /etc/redhat-release.5
# echo redhat-4 > /etc/redhat-release

OK… as root we have now finished!

Now log in with the oracle user and download the Oracle Client 10g from Oracle website: once there get the file called 10201_client_linux32.zip. Unzip and run the client:

# unzip 10201_client_linux32.zip
# cd client
# ./runInstaller

I pointed the oraInventory directory to /opt/oracle in the first screen; in the second one I choose to install the Oracle 10g Client in /opt/oracle/product/10.2.0/client_1/. Just before the installation finishes it prompts to you to execute two more commands as root: in my own installation I run

//execute the following commands as root
# /opt/oracle/orainstRoot.sh
# /opt/oracle/product/10.2.0/client_1/root.sh

but, as you may guess, your path may be different from mine.

Now the final step: we have to restore the /etc/redhat-release file we changed before:

# mv /etc/redhat-release.5 /etc/redhat-release

I hope this tutorial can help you… if you find errors please report them to me and I will correct as soon as possible.

The  first thing is to get the HP-UX PA-RISC install server CDs from HP website:if you do not have the original CDs you can get them as trial from here.

Now its time to install the Disk Agent on the server you need to backup; you need to install a package that is not installed by default on the Ubuntu Linux 7.04: inetd. So, as “administrator”, execute the command:

> sudo apt-get install netkit-inetd

to get the needed package installed.

Insert the first CD of the HP-UX PA-RISC install server on the optical drive of the server and mount it:

> mount /dev/hda /mnt

Now it is install time:

> cd /mnt/LOCAL_INSTALL
> ./omnisetup.sh

Answer all the questions the installer asks to you and finish the installation. In my installation the Data Protector agent was correctly added to the inetd configuration:

> cat /etc/inetd.conf
omni stream tcp nowait root /opt/omni/lbin/inet inet -log /var/opt/omni/log/inet.log

OK… we are at the end…

> /etc/init.d/inetd restart

and now try if the Data Protector agent answers to port 5555:

> telnet localhost 5555

That’s all… if you encounter any problem leave a comment here… I’ll try to help you.

Leave a comment even if you have a smarter method… I am very glad to learn.

The  first thing is to get the HP-UX PA-RISC install server CDs from HP website:if you do not have the original CDs you can get them as trial from here.

Now its time to install the Disk Agent on the server you need to backup; you need to install two packages that are not installed by default on the Red Hat Enterprise Linux 5: ncompress and xinetd. So, as root, execute the command:

# yum install ncompress xinetd

to get the needed packages installed.

Insert the first CD of the HP-UX PA-RISC install server on the optical drive of the server and mount it:

# mount /dev/hda /mnt

Now it is install time:

# cd /mnt/LOCAL_INSTALL
# ./omnisetup.sh

Answer all the questions the installer asks to you and finish the installation. In my installation the Data Protector agent was not correctly added to the xinetd configuration… look if you find the omni file in /etc/xinetd.d… if you do not find it create it with the following content:

service omni
{
socket_type = stream
protocol = tcp
wait = no
user = root
server = /opt/omni/lbin/inet
server_args = inet -log /var/opt/omni/log/inet.log
disable = no
}

and verify it is owned by root and with 644 permissions.

OK… we are at the end…

# /etc/init.d/xinetd restart

As suggested by fluffy on comment #1 now you have to check if the firewall (iptables) is actually active: if the firewall is switched on you have to permit the traffic from and to port 5555 to flow regularly.

# chkconfig –list | grep iptables
iptables 0:off 1:off 2:off 3:off 4:off 5:off 6:off

If you any on you need to modify the file /etc/sysconfig/iptables adding:

-A RH-Firewall-1-INPUT -m state –state NEW -m tcp -p tcp –dport 5555 -j ACCEPT

Now everything should be ok… let’s try if the Data Protector agent answers to port 5555:

# telnet localhost 5555

That’s all… if you encounter any problem leave a comment here… I’ll try to help you.

Leave a comment even if you have a smarter method… I am very glad to learn.

What is truecrypt?

As you can read in Truecrypt homepage:

Free open-source disk encryption software for Windows Vista/XP/2000 and Linux

So with Truecrypt you can encrypt you private files on a disk (on a real disk or on an encrypted file). This tutorial is needed because neither Truecrypt nor Scramdisk (the very useful GUI to use Truecrypt) were not already debianized in Ubuntu Edgy 6.10.

Prerequisites

The first thing you need is the Linux kernel source you are running:

> sudo su #we are going to work as root
> cd /usr/src #change to the appropriate directory
> apt-get source linux-image-`uname -r` #get linux sources
> CTRL-D #We want to leave the root user as fast as possible

Now you’ll get you Linux sources in /usr/src.
Last dependency is dmsetup:

> sudo apt-get install dmsetup #get dmsetup package from Ubuntu archives

Truecrypt

Now that we have all dependencies we can get, compile and install Truecrypt:

> cd /tmp #move in a working directory
#download the sources
> wget http://www.truecrypt.org/downloads/truecrypt-4.3a-source-code.tar.gz
#decompress the sources
> tar zxvf truecrypt-4.3a-source-code.tar.gz
#move in the Linux directory
> cd truecrypt-4.3a-source-code/Linux/
> sudo su #now we need to be root
> ./build.sh #answer the questions and compile
> ./install.sh #install everything
#We want to leave the root user as fast as possible
> CTRL-D

OK… we are almost arrived Truecrypt now should be compiled and installed… let me know if something is not going as expected and I’ll try to help you out.

What is scramdisk?

As you can read in Scramdisk homepage:

SD4L is a suite of Linux tools and a graphical user interface (GUI) which allow the creation of, and access to ScramDisk encrypted container files. In particular, SD4L provides a Linux driver which enables mounting ScramDisk containers. ScramDisk for Linux also encrypts partitions on a hard disk or storage media such as USB sticks or floppy disks entirely as devices. Version 1.0 and later versions, moreover, support TrueCrypt containers.

Installing scramdisk is easy as using it: it is not packaged by Ubuntu but scramdisk developers debianized it even for the ancient Ubuntu Edgy 6.10:

> cd /tmp #move in a working directory
# for 32bit systems
> wget http://ovh.dl.sourceforge.net/sourceforge/sd4l/ScramDisk_1.2-0_Ubuntu-6.10_2.6.17_i386.deb
# for 64bit systems
> wget http://switch.dl.sourceforge.net/sourceforge/sd4l/ScramDisk_1.2-0_Ubuntu-6.10_2.6.17_x86_64.deb
> sudo dpkg -i ScramDisk_1.2-0_Ubuntu-6.10_2.6.17_*.deb #install it
> scramdisk #use it

The end

OK… hopefully everything should have worked and know you have the latest Truecrypt and the latest scramdisk installed on you PC: put them at good use

Let me know if you encountered a problem… I’ll try to help you. Please leave a note even if you find this tutorial vaguely useful and help me to improve it.