You could work around this by plugging in a monitor, mouse, and keyboard and letting the OS boot and then removing the monitor when the boot process has finished. This is a far from ideal solution. Fortunately the Linux community has come up with a temporary work around for this issue (I’m confident the distribution developers will come up with a much better solution soon). Let’s take a look at the solution.

Warnings

This solution requires that you create an /etc/X11/xorg.conf configuration file. I assume that anyone wanting to set up a headless server isn’t afraid of manually creating/editing the xorg.conf file. If you are, make sure you back up any pre-existing xorg.conf file that might live in /etc/X11.

This guide also assumes that you already have a working server installation that you can successfully boot with an attached monitor. I will also assume you know what graphics card is in your server. You will need this information momentarily (so if you don’t know it, dig around and find out what card you are using). With that being said, let’s get on with it.

xorg.conf

The first thing you need to do is to set up the xorg.conf configuration. If one already exists, copy it to /etc/X11/xorg.conf.OLD and then erase the contents of the /etc/X11/xorg.conf file. The new contents of that file will be:

Section "Device"
Identifier "VNC Device"
Driver "vesa"
EndSection

Section "Screen"
Identifier "VNC Screen"
Device "VNC Device"
Monitor "VNC Monitor"
SubSection "Display"
Modes "1024x768"
EndSubSection
EndSection

Section "Monitor"
Identifier "VNC Monitor"
HorizSync 30-70
VertRefresh 50-75
EndSection

Once you have saved and closed that file you now need to edit the /etc/default/grub file and add the following line:

GRUB_CMDLINE_LINUX="nomodeset"

You can take this one step further and disable the splash screen for the boot process by setting the line:

GRUB_CMDLINE_LINUX_DEFAULT=

to “quiet” instead of “quiet splash”

Save the /etc/default/grub file and then issue the command sudo update-grub to rebuilt grub.

To test this setup go ahead and boot the machine without the monitor attached. Once you have given it plenty of time to boot you can either VNC or ssh into the machine. If you get a successful connection you are good to go. If you do not get a successful connection plug the monitor back in and see where in the process it stopped. If you have a black screen revisit the configuration and make sure everything is correct. To further troubleshoot boot the machine with the monitor plugged in and check the /var/log/Xorg.0.log file for any errors. Hopefully you will find the setup above works like a champ.

One such tool is the gadmin-samba tool from the Gadmintools suite of GUI Linux administration tools. The Gadmintools suite allows you to easily setup Samba with the help of a well thought-out graphical interface. With this tool you should be able to have Samba up and running in no time. Of course, there is a bit of installation to tackle at first, but even that is simple. So, without further adieu, let’s get to work.

Installation

You can do this two ways:

• Install the entire Gadmin suite of tools.
• Install only the Samba tool.

You will also need to make sure Samba is installed as well as winbind. So open up Synaptic and search for the following:

• samba
• winbind
• gadmin-samba

Mark each of those for installation and they should pick up all of the necessary dependencies. Once installed, you are ready to rock.

Running Gadmin-Samba

Figure 1

To start the tool go to the System Tools sub-menu of the Applications menu and select Gadmin Samba. You will have to enter your sudo (or root user – depending upon your distribution) password. The main window will open with no configuration settings filled in (see Figure 1).

I will go through the setup one tab at a time.

Server settings

Although there are numerous settings to configure, you really only need configure a few of these to get a basic Samba server up and running.

• The servers host name: This is actually the Netbios name as configured in smb.conf.
• Workgroup: The workgroup your Samba server will be a part of.
• Security level: Setting this according to your needs (I prefer users on a smaller network).
• Allowed hosts and networks: Set this to eth0 lo (you might have to modify eth0 to reflect your network device name).

That’s it for this tab. Now we move on to the users tab.

Users

Figure 2

The Users tab is exactly what you would expect – a means to set up users for your Samba share. This section takes the place of having to use the smbpasswd command. From this tab (see Figure 2) you will need to fill out:

• Username: The name of the user.
• Password: The password for the user.
• Group: You must add your user to a group. You can safely add your user to the same name as the username. So if your username is joe, you can add this user to the joe group.
• Comment: For some odd reason, comments are required.
• Home directory. Set this to the users’ home directory.
• Shell: Most likely this will be /bin/sh

After you fill out this information click the Apply button. You are now ready to move on to the Shares tab.

Shares

Figure 3

When you click on the Shares tab you might be surprised to see some default values in place. If not, don’t worry, this is simple. Just configure the following:

• Share name: The name of the share you want to create.
• Shared directory: The directory you want to share out. By default, Gadmin Samba will want to share out /opt/samba. This is fine if you like, but you must remember that your normal users will not have write permission to this directory. That’s okay, you can add users to this directory by scrolling down and clicking the “Add access permissions” button and walking through the wizard. Just use caution with this. If you add users to the share, only those users will have access to the share. This is good security, but you must remember to add new users to this share should new users need access.

Once you have configured your users, you can click on the Configuration tab to see what your /etc/samba/smb.conf file will look like and click the Save button should it suffice. Once you have saved your configuration file, click the Activate button and Samba will up and running, ready for your users to connect.

Final thoughts

The Gadmintools Samba GUI has taken the complexity out of setting up a Samba server. Give this tool a try and see if you can’t get your Samba server up and running faster and with less hair pulling than you ever did with your manual setups.

Of course there are variations on that opinion. But that is neither here nor there. The purpose of this tutorial is to help you get a PostgreSQL server up and running quickly and easily. To make this simple we will make this a part of our Ubuntu Server series, so all you have to do is have your Ubuntu Server up and running (see my article “Installing Ubuntu Server 9.04” to get started.) Once you have that server up and running you are ready to get your PostgreSQL server up.

Installation

The first thing you need to do is to install the necessary software. Since this is Ubuntu, it’s quite easy. Open up a terminal window and issue the command:

sudo apt-get install postgresql

Once the software is installed you are ready to set it all up.

Change the default user password

One of the first steps you want to take is to change the default password for the user postgres. Sine we are using Ubuntu you will have to use the sudo command to change to the postgres user like so:

sudo su – postgres

You will have to enter your sudo password after which you will now be issuing commands as the user postgres. The next step is to gain access to the postgresql command prompt with the command:

psql

Your new command prompt will look like:

postgres=#

NOTE: The only user that can open the PostgreSQL prompt without defining a database to work with is the user postgres. Other users would have to gain access to the command prompt with a command like:

psql DB_NAME

Where DB_NAME is the name of an existing database.

Changing the password is as simple as issuing the command:

\password postgres

You will then be asked to enter a password and then verify that password.

Your default password has not been changed. You can exit from the PostgreSQL prompt by issuing the command:

\q

Create a database

Now, while still logged in as the postgres user, let’s create a database. For this you do not have to be logged into the PostgreSQL command prompt. Instead just issue the command:

createdb testdb

Where testdb is the name of the database you want to create. To check to make sure that database was created go back to the PostgreSQL command prompt (remember, the command psql) and enter:

\l

You should see a listing for your new database like:

testdb | postgres | UTF8 | en_US.UTF-8  | en_US.UTF-8

Once again, log out of the PostgreSQL command prompt with the command:

\q

Create a user

By default, the only user that can connect to a database is the postgres user. This will be of no help when you need to connect with another user. To create a new user (that can connect to databases) you would issue the command (as the user postgres):

createuser –superuser USERNAME

Where USERNAME is the name of the user you want to create.

Final thoughts

Now you should have a basic PostgreSQL installation with a test database and a user, besides postgres, that can work with the tools. Next time we work with PostgreSQL we’ll discuss more challenging issues with this outstanding database tool.

When you spend a lot of time creating and administering the web/mail server combination, it’s always good to have a solution that is easy to put in place. I have found one that I have used for a while now and trust its security and ease of use. This “system” uses a fairly complex iptables script that has just a single line that you will need to modify in order to have sound security for a web/mail server that serves up web pages via Apache on port 80 and mail via SMTP on port 25 and IMAP via port 143. Included in this script is the inclusion of port 25 for secure shell access.

You will be surprised how simple this script is to use. I have uploaded the script to a pastebin site which you can access using this address. Copy that script to your Linux server (for the sake of simplicity save it in ~/scripts, which you will create) and you are ready to set the system up.

Configuration

The only line you need to configure (unless you need to change the networking device name and/or want to include extra ports or remove ports from the script) is line 8. This line looks like:

SCRIPT_DIR="/PATH/TO/DIRECTORY"

What you want to have there is the location that will be filled with any IP address blocked by the firewall. For the purposes of this tutorial it will be saved in ~/scripts.

Once you have that edited you can save the file and call it start_iptables.sh. Now give the file executable permission with the command:

chmod u+x start_iptables.sh

Now create a new file called stop_iptables.sh. The contents of that file will be:

iptables -F
iptables -X
iptables -t nat -F
iptables -t nat -X
iptables -t mangle -F
iptables -t mangle -X
iptables -P INPUT ACCEPT
iptables -P OUTPUT ACCEPT
iptables -P FORWARD ACCEPT

Make that file executable with the command:

chmod u+x stop_iptables.sh

The former script will start your firewall, the latter script will stop it.

Starting this script

You can start and stop this script any time you feel like with the command:

sudo ~/scripts/start_iptables.sh

If there are no errors you should see something like:

Starting IPv4 Wall…

You can also check to see by listing all of your iptables chains with the command:

sudo iptables -L

Stopping the firewall is done with the command:

sudo ~/scripts/stop_iptables.sh

Start at bootup

Now let’s make it such that the firewall script starts upon boot of the server (should the need arise).  Open up the /etc/rc.local file and add the line:

/PATH/TO/scripts/start_iptables.sh

before the “exit 0″ line.

Where /PATH/TO/ is the explicit path to the ~/scripts directory (you can’t use “~/” in rc.local).

The script will now start at boot.

Final thoughts

This easy to install firewall will add a level of saftey to your web/mail server that would be hard to come by with a GUI tool. And if you are using a headless (console only) server, it’s the only way to go.

GASP!

Never fear, it’s not that hard. Just a few commands and you’ll be up and running with your new hard drive installed on your server. This article will assume the physical drive is already installed on your machine.

I am going to make a couple of assumptions here, for the sake of simplicity for this article. The first assumption is that the new drive will be mounted to the directory /data. The next assumption is that you want this directory to be both readable and writable by all users on the system. Another assumption is that you will want the drive to be formatted with the ext3 file system with just one partition. Finally I will assume you want this drive to be automatically mounted upon boot of the system.

With that out of the way, let’s get down to business.

Once you boot the machine with the new drive log into the console and issue the command:

dmesg

Near the bottom of the output you should see where the disk is located. it will be something like:

/dev/sdb

So let’s assume it is on /dev/sdb.

If you can’t figure it out where the drive is located  with dmesg issue the command:

sudo fdisk -l

The above command will report something like:

/dev/sda1 * 1 18709 150280011 83 Linux
/dev/sda2 18710 19457 6008310 5 Extended
/dev/sda5 18710 19457 6008278+ 82 Linux swap / Solaris

But will include a listing for your new drive. If you only see listings for /dev/sda* then your new drive has not been recognized and there is a problem with the physical installation.

Once you know where your drive is located (again we’ll use /dev/sdb for our example) it’s time to create a new directory where this drive will be mounted. We are mounting our drive to the directory /data so we’ll create this directory with the following command:

sudo mkdir /data

Now let’s make it available to all users:

sudo chmod -R 777 /data

With a place to mount the drive, it’s time to format the new drive. The formatting will be done with the command:

sudo mkfs.ext3 /dev/sdb

When this is complete you are ready to mount the drive. Before you edit fstab entry (so the drive will be automatically mounted) make sure it can be successfully mounted with the command:

sudo mount /dev/sdb /data

If this is successful let’s create an entry in /etc/fstab. open that file with the command

sudo nano /etc/fstab

Now add the following entry at the end of that file:

/dev/sdb /data ext3 defaults 0 0

Once you save that file, mount the drive (without having to reboot) with the command:

sudo mount -a

To make sure the drive mounted successfully issue the command:

df

The above should include in the report:

/dev/sdb   /data

If that’s the case, success! You can run one file test by trying to write a file to the new drive with the command:

touch /data/test

If you can write that file all is well.

Final thoughts

Yes it is a bit more complicated than adding a new drive when you have GUI tools available, but it’s not anything that can’t be accomplished by the average user. If you are not afraid of the command line, you can add a second drive in Ubuntu with ease.

Mantis is an open source bug tracking tool that is as feature-rich and stable as it is free. It is written in PHP and works with MySQL, MS SQL, and PostgreSQL databases. Mantis can be installed on Linux, Windows, and OS X and can use nearly any modern web browser.

Features

Naturally, before you try a bug tracking software, you will want to see the feature listing. Mantis Bug Tracking includes such features as:

• Simple or Advanced issue pages.
• Multiple projects per instances.
• User access levels.
• Projects, sub-projects, and category support.
• Built in reporting.
• Custom fields.
• Email notification.
• Issue monitoring.
• Sponsorship support.
• Issue report via email.

And much, much more (for a full list see the Mantis Feature List page). But enough said with the what, let’s get on with the how.

Getting and installing

The first step is to download the file. You can download the latest, stable release from the Mantis Sourceforge site. Once you have that file move it into the Apache document root with the command:

sudo mv mantis-XXX.tar.gz /var/www/

Where XXX is the release number.

Now unpack the tar file with the command;

sudo tar xvzf mantisbt-XXX.tar.gz

Where XXX is the release number.

Now change the name of the mantis directory with the command:

mv mantisbt-XXX mantis

Where XXX is the release number.

Before you move on to the web-based installation, you need to create a database. I use phpmyadmin to do this (Read how to set this up in my article “Install phpmyadmin for easy MySQL administration“.) Create a database called “bugtracker” (no quotes). Once you have done that you then need to go to the file /var/www/mantis/config_inc.php.sample and edit the Database Settings variables. You will need to edit the variables:

• g_hostname
• g_db_username
• g_db_password

Make these reflect your particular installation. Once you have that finished change the name of that file to config_inc.php and you are ready to check your installation.

You are now ready to point your browser to:

http://ADDRESS_OF_SERVER/mantis/admin/

Where ADDRESS_OF_SERVER is the actual IP or URL for your server.

You will see four links:

• Check your installation.
• Upgrade your installation.
• Modify stylesheets.
• System utilities.

Click on the Check your installation link. This address will take you to the page that will check your server for all the necessary requirements for installation. Once that passes you are ready for the installation.

Web-based setup

Figure 1

Now point your browser to http://ADDRESS_OF_SERVER/admin/install.php This page will walk you through the steps for the database setup (see Figure 1.)

Oddly enough it looks like you are being asked to create an admin acccount here. You’re not, for the Admin Username/Password you will want to use the same Username/Password that you used for the Database user.

Fill that information out and click the Install button. The next page will greet you with a bunch of information that informs you (Hopefully) that everything passes. At the bottom of that page is a small link to continue with login. Click that link and you will find yourself at the Mantis Log In screen. The default username/login for a mantis installation is:

Username: administrator

Password: root

The first thing you will want to do, upon logging in, is to change the account information for this login. Click on the My Account button and make the necessary changes.

You are now ready to start using your Mantis Bug Tracking system.

Final thoughts

I have found the Mantis Bug Tracking system to be one of the easiest to use in a category that is often filled with overly complicated tool (either to install or use). I think you will find that Mantis meets (or exceeds) all of your bug tracking needs.

Now that you already have your Ubuntu Server up and running, adding FTP is actually quite easy. There are numerous FTP servers available, but the one I tend to prefer is vsftpd. Not only is it more secure than many other FTP servers, it’s easy to install and configure, even for anonymous use.

In this article you will see how to get vsftpd installed and configured for both user login and anonymous use.

Installing vsftpd

Since the installation for the base server is a GUI-less Ubuntu 9.04, the entire installation and configuration will be done from the command line. Log into your server and then issue the following command:

sudo apt-get install vsftpd

The above command will install everything needed for your FTP server. What you will find is your configuration file located in the /etc directory and the executable located in /etc/init.d/. By default vsftpd is installed to allow ONLY anonymous download. The default location for anonymous files is in /home/ftp. So by default all you need to do is place files you want to be accessible anonymously in /home/ftp, start the vsftp daemon with the command:

sudo /etc/init.d/vsftpd start

And you can immediately connect anonymously. Any file located within /home/ftp will be available to anonymous users. That’s not a bad setup for an internal LAN. But if you need to control what people use/see, or if you do not want to allow anonymous access, you will have to take care of a little configuration.

Configuring user-authenticated login

Let’s say you have four users on your system that need access to their own individual accounts. For this you will need to enable user-authenticated login. This is done within the /etc/vsftpd.conf file. Open up this file and scroll down to around line 26. Here you will see the entry:

#local_enable=YES

Notice the “#” symbol at the beginning of the line? This means that line is commented out. Remove the “#” symbol, save the file, restart vsftpd, and now anyone with an account on your ftp server can log in with their username and password.

But what if the users need to upload as well as download? Simple. Below the local_enable line you will see the line:

#write_enable=YES

Uncomment out that line and restart vsftpd to enable write access for your users. Remember, you have to restart vsftpd any time you make a change to the configuration file. You can also disable anonymous access by commenting out the line:

anonymous_enable=YES

This can be handy for departments as well. Say you have an editorial department, a graphics department, and an accounting department. You will have to have those accounts added to the system. You can add those accounts (and their home directories) with these commands:

sudo useradd -m ACCOUNT_NAME

sudo passwd ACCOUNT_NAME

Where ACCOUNT_NAME is the name of the user account to create. The above commands will create the user, the users’ home directory, and give the user a password.

Once these accounts have been created you can log into the FTP server with the username and password.

Final thoughts

Setting up an FTP server couldn’t be any easier. With the Ubuntu Server already up and running, you can have anonymous ftp set up in about a minute.

Ubuntu Server is, in my experience, one of the finest servers on the Linux landscape. This server distribution can be used for just about any server needs. But one thing to be warned about – it is headless. With the Ubuntu server you can have just about any server package you can think of, but don’t expect a GUI to help you along. And due to its headless nature, it is faster than a desktop-based counterpart. But what is it like to install?

Let’s find out.

NOTE: This particular installation will be done in a Virtual Machine using VirtualBox. So any oddities (or small hard disk sizes) you see will be due to that.

Figure 1

The first step is to insert the CD of Ubuntu Server (I am using 9.04) into the machine and boot. The first screen you will see is the language screen (see Figure 1).

In the language section you just use the up and down keys to migrate through the various languages available and, when you land on the correct language, click the enter key.

Figure 2

The next step (see Figure 2) gives you a few different actions to take.

Here you can start the installation by selecting “Install Ubuntu Server” or you can check the disk, test the memory on your machine, bypass the installation and start from your hard drive, or use this disk as a rescue disk.

Go ahead and select “Install Ubuntu Server” and click the Enter key.

Figure 3

The nex screen (see Figure 3) again is asking you to choose a language. The difference between this language selection and the first language is that this language selection will be the language used on your actual server, whereas the original language screen was for the installation process. You select the language using the same technique you did for the first language.

Notice the difference in color and style on this screen? This is the typical Linux text-based installation. Get used to it, because this is the look and feel for the rest of the installation.

Figure 4

The next screen (see Figure 4) has you select the country where you (or your server) reside. As you can see the selections offered for your country are based on the languages you chose. This selection is actually important because it will help configure your region-based settings.

You make this selection the same way you did the language (scroll up or down with your arrow keys). To make your selection hit the enter key.

Figure 5

The next screen (figure 5) is the keyboard selection screen. Most likely you can just use your left arrow key, move to <Yes> and then hit the enter key. If you’re not sure  select <No> and you will walked through a very simple keyboard selection wizard that will ask you if certain keys are present. This will narrow down your selection. After you select <Yes> and hit enter the next window will ask for the original of your keyboard. Select the country associated with your keyboard and hit the enter key. After that you will need to further narrow down your keyboard selection by choosing the layout type. I leave the last two screens out because they should be very obvious to you.

Figure 6

The next few screens require no interaction on your part. It isn’t until you finally get to the Hostname screen (see Figure 6) that you will have to do anything.

The hostname will be the “nickname” your machine will be known for on your network. It is a single word name. Say this machine will be your mail server. For that you can name the machine “mail”.

Once you have entered your hostname click the tab button until <Continue> is slected and press Enter.

Figure 7

The next screen (Figure 7) requires you to enter your time zone. Make sure you select this properly because it will effect many services on your machine. If your machine is an email server it could incorrectly stamp all incoming email with the wrong time (if  the wrong zone is selected).

Scroll through the listing with the up and down arrows and, once you have highlighted the selection you want, click the Enter key.

Figure 8

The next screen (see Figure 8) sets up the disk partitioning scheme. You have four choices. Only one of these choices is manual which should only be used by more experienced users. Of the other choices you will want to stick with one of the LVM options only if you already know how to set up LVM. LVM is the Logical Volume Management scheme which is much more flexible than a standard scheme. If you choose to use LVM you can then choose if you want your disk encrypted or not. An encrypted disk will be slightly slower than a non-encrypted disk, but it will be much more secure. The easiest partition method is to select “Guided – use entire disk”. For a default Ubuntu Server, I always select this.

Figure 9

The next screen (Figure 9)  is just a confirmation window showing you what the installer is about to do to your disk and is it okay. If what you see listed is okay, select “Finish Partitioning and write changes to disk” by using the Tab key and then hit the enter key.

After that you will have one more chance at making changes because the next screen asks for you to verify the changes. Tab to <Yes> and click enter on this screen.

Figure 10

Depending upon the size of the disk you have partitioned, the partitioning process could take a while. Once the paritioning is complete the installation will start. This will take a bit of time (but far less time than you are used to for an operating system installation). Figure 10 was taken after about 30 seconds into the process and the installation of the base system was already at 31%.  Don’t be fooled. This is not 31% of the entire installation. This is just the base packages like the kernel. You will still have to install the packages you need for your server.

The next three screens are all dedicated to creating a user account. You will will first enter a full name for your user, then a login name for your user, followed by a password for your user. Once you are done with those you will be at the next important screen.

Figure 11

The next window (see Figure 11) asks if you want to encrypt your /home directory. If you plan on having log in users on the system it might be a good idea to encrypt the data. If, however, you don’t think the /home directory will be used all that much (say this will be a public web server) this isn’t that necessary.

After that screen you will be presented by a screen asking if you need to set up a proxy. If you need a proxy enter the address in the blank space, tab down to <Continue> and click Enter. If you do not need a proxy just tab down to <Continue> and click Enter.

Figure 12

The next screen will, depending upon how fast your network connection is, seem to hold for a bit. This screen is scanning the mirror for packages.

You will then proceed to the updates section. If you want to have all of the updates applied automatically you will want to selec the “Install security updates automatically”. If you prefer to handle the updates on your own select “No automatica updates”. You can also use Landscape which is a web-based updater. If you want the easiest method, my suggestion is to go with automatic updates.

Figure 13

The next screen is the longest screen, because it is the package installation screen. But during this you will be given the change to select the software you want (see Figure 13). This porition is set up easily.

You can use the arrow keys to move up and down and then select a package with the space bar. From this list you can see what types of servers can be installed. If you go to Manual selection make sure you know what you need. Tab down to continue and then hit Enter when you’re ready to install.

The installation process will now download the necessary packages, based on the packages you selected.

Depending upon the packages you selected you might have to handle a few configuration options. For example, if you are installing a LAMP server, you will be prompted for a MySQL password for the “root” user. If you are prompted for this, type the password and hit Enter. Most likely you will be prompted for the MySQL password three times.

Figure 14

After the package installation is complete you will see the installer automatically take care of the GRUB installation/configuration as well as some clean up tasks. When you reach the final screen (Figure 14) you are complete! You can now reboot your Ubuntu Server installation and enjoy.

In this article you will see how to install Nagios on a working Ubuntu Server installation. The release I used was 9.04, but you should be able to use 8.04 just as easily.

Features

You want features? Nagios is full of them. Nagios can monitor your entire network, you can handle problem remediation, you can plan network downtime, you can watch hosts, systems, services, applications..there’s very little you can’t do with Nagios.

But let’s think about this installation. The best (and really only good) way to install Nagios is from source. This means you are going to have to do some compliation. Don’t worry, it’s not hard…when you have a step-by-step guide that is.

Before you start

If you are using, as I did, a Ubuntu server installation, you will need to install a few tools first. So from the command line (on your Ubuntu server) issue the following commands:

sudo apt-get install php5-gd

sudo apt-get install gcc

sudo apt-get install make

The above commands will install the tools you need in order to get Nagios installed. If you don’t install the above, you won’t be able to complete the installation.

Installing Nagios – preflight

Before you actually run the installation you will need to take care of some user/group accounting first.

Create the user nagios:

sudo useradd -m nagios

Give the nagios user a password:

sudo passwd nagios

NOTE: You will have to enter the new password twice for the above command.

Create the group nagios:
sudo groupadd nagios

Add the user nagios to the group nagios:

sudo usermod -G nagios nagios

Create the group nagcmd:

sudo groupadd nagcmd

Add the user nagios to the group nagcmd:

sudo usermod -a -G nagcmd nagios

Add the Apache user to the group nagcmd:

sudo usermod -a -G nagcmd www-data

Installing Nagios and Nagios Plugins

The first thing to do is to download the files you need. Issue the commands:

wget http://osdn.dl.sourceforge.net/sourceforge/nagios/nagios-3.0.6.tar.gz

and

wget http://osdn.dl.sourceforge.net/sourceforge/nagiosplug/nagios-
plugins-1.4.11.tar.gz

to download the files you need.

Untar the Nagios file with:

tar xvzf nagios-3.0.6.tar.gz

Change into the newly created Nagios directory with the command:

cd nagios-3.0.6

Now run the configure script using the nagcmd defined as the command group with the command:

sudo ./configure –with-command-group=nagcmd

Time to compile:

sudo make all

Time to install everything:

make install

make install-init

make install-config

make install-commandmode

Almost ready to finalize the installation of Nagios (before moving on to installing the plugins.) There is one simple configuration to take care of (for the basic installation). Open up the /usr/local/nagios/etc/objects/contacts.cfg file and add your email address as the contact email address. That’s the only configuration to change for now.

Configuring for the Web interface

There are just a few commands to run to configure the Web interface:

make install-webconf

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

/etc/init.d/apache2 reload

The final command above simply restarts Apache.

Install the plugins

Before you log into your Nagios installation you have to install your plugins first. Change to the directory you downloaded the Nagios files to and untar the plugins file:

tar xvzf nagios-plugins-1.4.11.tar.gz

Now change into the newly created directory:

cd nagios-plugins-1.4.11

Compile the plugins with the command:

sudo ./configure –with-nagios-user=nagios –with-nagios-group=nagios

Now install the plugins with the following commands:

make

make install

Fire it up!

Of course you want to make sure Nagios starts any time the system is restarted. Do this with the command:

sudo ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios

And finally, before you start up Nagios, make sure there are no errors with the command:

sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

If you see no errors reported, it’s time to start it up. Issue the command:

sudo /etc/init.d/nagios start

Nagios is ready to go. Point your browser to:

http://ADDRESS_OF_NAGIOS_SERVER/nagios

You should be ready to enjoy all that is Nagios. Congratulations.

In reality the message you see upon login is a combination of two files: /etc/motd and /etc/motd.tail. The former file is the file that is regenerated upon boot. The latter file contains static information. The first thing we will do is change the /etc/motd file so that, upon loggin in, the users can get system (or company) specific information. Once that is done we’ll trick /etc/motd.tail into getting content different than that from /etc/init.d/bootmisc.sh.

/etc/motd.tail

The first thing you should is open up your /etc/motd.tail file in your favorite text editor. When I open up that file in Ubuntu Server 8.10 the contents look like:

The programs included with the Ubuntu system are free software;
the exact distribution terms for each program are described in the
individual files in /usr/share/doc/*/copyright.

Ubuntu comes with ABSOLUTELY NO WARRANTY, to the extent permitted by
applicable law.

To access official Ubuntu documentation, please visit:
http://help.ubuntu.com/

I want to change that content so I know exactly which server I am on when I log in. So let’s say I want to change that to say:

welcome to the Ubuntu Server. have a good time and do not break anything.

Now when I log into my Ubuntu Server I will see the following motd:

welcome to the Ubuntu Server. have a good time and do not break anything.

System information as of Mon Apr 6 15:00:01 EDT 2009

System load: 0.0 Swap usage: 0% Users logged in: 1
Usage of /: 18.5% of 13.46GBTemperature: 52 C
Memory usage: 43% Processes: 104

Graph this data and manage this system at https://landscape.canonical.com/
Last login: Mon Apr 6 15:06:41 2009 from 192.168.1.8

As you can see there is some useful information to be had with this. But you may not want all of your users to see this information. Say you want to first let the users know which server they are on. We’ve already covered that with /etc/motd.tail. But let’s say you also want to send out a message to all users who log onto the server. You can change /etc/motd to reflect that message but when you reboot the machine that message will be replaced. So to get around that we can create a shell script that will over write the information written at bootup. A possible (and overly simple) shell script could look like this:

#!/bin/bash
rm /etc/motd
touch /etc/motd
echo "this is my message" > /etc/motd

Save that file in, say /opt (for example sake we’ll call it /opt/motd_append) and make it executable with the command chmod u+x /opt/motd_append. Now to make sure this command runs we can create an entry at the end of /etc/rc.local like this:

/opt/motd_append

Now when /etc/rc.local runs the script will run and over write the information in /etc/motd. Now when your users log in they will see your special message every time.

In this article we will examine the different Ubuntu Linux spin offs, highlight what each spin off is about, and decide who that spin off would suit. Hopefully, in the end, you will know exactly which *buntu ISO to download, burn with your CD or DVD burning, and install on your computer.

What is a derivative and why would I want to use one?

A derivative takes the original (in this case Ubuntu Linux) and alters it to fit a particular need or audience. As for Ubuntu there are quite a few derivatives and each one targets a very specific need. That specific need is why you would want to use a derivative. Say, for example, you are a teacher and you have specific needs from your operating system. There is a derivative for you. Or say you want KDE instead of GNOME. There i a derivative for you.

With that in mind, let’s take a look at what derivatives are out there and who they are for. First we will look at the officially supported Ubuntu derivatives.

Edubuntu

If you are in the business of education as either a teacher or a student, and you need software to fit those specific needs, Edubuntu contains everything you would need to teach a class, be in a class, or learn about a class. Edubuntu contains software for math, science, writing, educational games, and more. As for target age, Edubuntu is useful for elementary school through graduate school.

Kubuntu

The default Ubuntu “ships” with GNOME. Although GNOME is an outstanding desktop environment, there are those that will prefer the KDE desktop environment. For those fans of KDE who do not want to have to spend the time installing KDE, Kubuntu is for you. Kubuntu is now defaulting to KDE 4.x.

Ubuntu Server Edition

If you are looking for a reliable and fast server installation that contains nearly everything you need for a server by default, the Ubuntu Server Edition is for you. But be warned, this is a text-based install as well as a GUI-less operating system. So to use the Ubuntu Server Edition you best bone up on your command line skills.

And now for the Recognized derivatives.

Xubuntu

If you’re looking for a full-blown Ubuntu installation that has smaller hardware requirements than the stock GNOME or KDE based Ubuntu, Xubuntu might be for you. Xubuntu uses the Xfce window manager to keep system requirments as low as possible while still offering as much user-friendliness as possible.

Gobuntu

If you long to have an operating system completely free of restrictive licensing then Gobuntu is for you. Gobuntu endeavors to hold true to the Free Software Foundations’ four freedoms:

• The freedom to run the program for any purpose.
• The freedom to study how the program and adapt it to fit it to your needs.
• The freedom to redistribute your modified program.
• The freedom to improve the program.

So using Gobuntu you can rest assured that the included software will ahere to the four freedoms. This can cause problems if you have hardare that depends upon restricted drivers (such as NVidia cards).

Ubuntu Studio

If you have serious multimedia needs Ubuntu Studio is for you. This derivative includes: Ardour (professional-level audio tools); Gimp, Inkscape, and Blender (Graphics tools), PiTiVi, Kino, and Cinepaint (Video tools). What Ubuntu Studio does is install all of these tool for you so the end results is an outstanding distrubtion ready to fulfill your multimedia needs.

MythBuntu

If you need a media center PC and you want it based on an open source operating system, Mythbuntu is the OS you’ve been looking for. Once you have met all of the hardware requirements for your media setup, this Ubuntu distribution makes creating a stand-alone PVR system a snap. And because your media center will be powered by Ubuntu, you can bet that media center will serve as a standard desktop or a server. With MythBuntu you can meet many needs with one distribution.

And some unofficial derivatives

Eeebuntu

Eeebuntu replaces the default operating system on your Eee PC. But Eeebuntu isn’t just a replacement for your Eee operating system, it is definitely an upgrade. Eeebuntu will make your Eee PC seem more like a standard PC than many other Netbook respins.

CrunchBang

I hadn’t heard of Crunchbang, but with a name like that I had to look. Of course CrunchBang is a relevant derivative because it uses the OpenBox window manager and GTK+ applications. That means an incredibly light weight distribution (even more so than Xbuntu.)

OpenGEU

This is my favorite Ubuntu derivative because it uses the Enlightenment (E17) window manager. It’s sleek, well done, and chock full of eye candy.

Final Thoughts

Have you found a derivative that would match your needs yet? The above list includes all of the officially supported and the recognized (as well as some unrecognized) derivatives. If one of these derivatives does? not meet your needs you could either roll your own or look at a different distribution. Fortunately Ubuntu and its derivatives cover a lot of ground.