Ubuntu Maverick Setup - part 2

Now that we've secured access to our Ubuntu Maverick slice we can update it and get it ready for the rest of the server install.


In part 1 of the Ubuntu 10.10 (Maverick Meerkat) setup, we completed the ssh configuration along with a basic iptables setup.

Now let's run some checks and install some personal configuration files to make life easier. Once done, we can update the install and create a solid base for the 'meat' of the server.

OS check

First thing is to confirm what OS we're using. We know we should be using Ubuntu Maverick but let's see:

cat /etc/lsb-release

You should get an output similar to this:

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=10.10
DISTRIB_CODENAME=maverick
DISTRIB_DESCRIPTION="Ubuntu 10.10"

Good.

Using free

Memory usage should be very low at this point but let's check using 'free -m' (the -m suffix displays the result in MB's which I find easier to read):

free -m

It's nice to know what is going on so let's look at that output:

.                  total       used       free     shared    buffers     cached
Mem:           254        55          199          0           2               21
-/+ buffers/cache:      30          223
Swap:            511        0           511

The line to take notice of is the second one as the first line includes cached memory - in this demo slice I have 254MB memory in total with 30MB actually used, 223MB free and no swap used. Nice.

.bashrc

Normally the "ls" command doesn't list files that start with a period. Those are usually configuration files or directories, and ls hides them so they don't clutter up your directory view. To see all of what's there, run:

ls -a ~

The "-a" option is what tells ls to list all files, not just the non-configuration files.

You'll see several files, but let's focus on ".bashrc" right now. This is ultimately where your user environment (the "shell") will look for its settings. Go ahead and open it for editing:

nano ~/.bashrc

Inside you'll see a lot of shell script commands — don't worry if you don't understand it all. Anything we add at the end of the file will override what came before. If you want to, say, change your prompt, you don't necessarily need to figure out what all the "if" statements in there by default are for, and which line you need to edit. You can just add your own setting at the end.

Custom prompt

With that in mind, let's look at how to change your prompt. At its simplest, the prompt's format is set with the "PS1" environment variable. It consists of some numbers that determine color and some codes that act as stand-ins for variables like the current working directory and your hostname. To set your prompt to just your hostname and working directory, both in different colors, you could add this line to the end of the .bashrc file:

PS1='\[\033[0;35m\]\h\[\033[0;33m\] \w\[\033[00m\]: '

The chunks like "0;35m" and "0;33m" are what control the colors - those are pink and brown, for example. Other colors you can substitute include "0;32m" for green and "0;36m" for blue — it's just a matter of changing those numbers.

Other important parts of that jumbled collection of characters are "\h" and "\w", which represent the hostname and working directory, respectively. If you wanted to include your username in the prompt you could add the "\u" code along with an "@" symbol, and it would look like this:

PS1='\[\033[0;35m\]\u@\h\[\033[0;33m\] \w\[\033[00m\]: '

Before we see what that will look like, however, let's also look at another useful feature of your shell, aliases.

Alias

The "alias" keyword lets you set a shortcut for another command. Some examples to get you started, which can be added to the end of your .bashrc file:

alias free="free -m"
alias update="sudo aptitude update"
alias install="sudo aptitude install"
alias upgrade="sudo aptitude safe-upgrade"
alias remove="sudo aptitude remove"

They're pretty simple examples, and are just meant to save you a little typing. Notice that you can essentially replace a command with an alias, like we did by setting the alias "free" to be a shortcut for "free -m". With that alias set, when you type "free" on the command line, behind the scenes the shell actually runs "free -m", so you don't have to type the extra characters to get the memory usage numbers in megabytes.

Similarly, those other aliases are shorthand for some aptitude commands to update or install packages. Since "sudo" is run behind the scenes you'll still have to type your password, but at least before that you won't have to type as much to run an update or install a package.

To activate the changes you've made to the .bashrc file, either log out and log back in or enter this command:

source ~/.bashrc

If you set a value for "PS1" above, you'll see your prompt change. Feel free to go back and change the colors or format of the prompt, or add your own aliases.

Set locale

You can check the current locale setting for your slice by running:

/usr/bin/locale

If the code doesn't match what it should be for the localization you would like to use for your slice (or if it uses a generic locale like 'POSIX'), run something like the following commands:

sudo /usr/sbin/locale-gen en_US.UTF-8
sudo /usr/sbin/update-locale LANG=en_US.UTF-8

'Something like' because you may want to use a locale other than US English. If so, substitute the language code for 'en' and the region code for 'US' above. The locale 'cy_GB.UTF-8' would designate Welsh for the language and Great Britain for the region, for example. A complete list of language and region codes can be found here.

If you change the default locale for your slice you will need to log out and log back in to see the change when running 'locale' by itself again.

Package repositories

An Ubuntu Slice comes with a basic set of repositories.

Have a look at the enabled repositories by running:

sudo nano /etc/apt/sources.list

You should see something very much like:

deb http://archive.ubuntu.com/ubuntu/ maverick main restricted universe
deb-src http://archive.ubuntu.com/ubuntu/ maverick main restricted universe

deb http://archive.ubuntu.com/ubuntu/ maverick-updates main restricted universe
deb-src http://archive.ubuntu.com/ubuntu/ maverick-updates main restricted universe

deb http://security.ubuntu.com/ubuntu maverick-security main restricted universe
deb-src http://security.ubuntu.com/ubuntu maverick-security main restricted universe

Each line specifies either a binary package repository ('deb') or a source package repository ('deb-src').

You can, of course, add more repositories whenever you want to but I would just give a word of caution: Some of the available repositories are not officially supported and may not receive any security updates should a flaw be discovered.

Keep in mind it is a server we are building and security and stability are paramount.

Update

Now we can update the package list that aptitude uses.

sudo aptitude update

NOTE: If you have used the .bashrc aliases shown above you just need to enter 'update' as the alias will use the entire command. I've put the whole thing here so you know what is happening.

Now we have set the locale and updated the sources.list repositories, let's see if there are any upgraded packages available:

sudo aptitude safe-upgrade

As with all installs have a careful look at the list and, once happy, press 'y' to continue.

That's really the basics done for the Slice.

Once any updates have been installed, we can move on to installing some essential packages.

Development Tools

Ubuntu has some handy meta-packages that include sets of pre-defined programs required for a single purpose.

So instead of installing a dozen different package names, you can install just one meta-package. One such package is called 'build-essential'. Issue the command:

sudo aptitude install build-essential

Notice the programs that are to be installed include gcc, make, patch and so on. All these are needed for many other programs to install properly. A neat system indeed.

Enter 'y' and install them.

You might get a message like this in aptitude's response when you go to install the development tools:

The following packages are BROKEN:
  libc6-i686

It's less of a problem than it sounds like, fortunately. It doesn't actually mean your system is broken, it just means aptitude did some checking on files and versions and decided something didn't add up.

If you do get that warning aptitude will also suggest a plan that will correct the offending package. Say yes to that, and then you can say yes to the actual installation. When aptitude installs the build tools it will also update the package it complained about, fixing the issue.

Now we have the necessary packages should we want to build an application from source.

Done

The console is now informative and less drab, locales have been configured and basic compile tools have been installed. Quite a lot happening here but now we have a more secured Slice with updated packages ready for the meat of the server to be put in place.

  • -- Jered

Article Comments:

Liutauras commented Fri Oct 29 11:48:12 UTC 2010:

Hi Jered, just wanted to point out that it looks like sudo aptitude is removed from Maverick at least for the moment. http://brainstorm.ubuntu.com/idea/25099/

Regards, Liutauras

Jered commented Fri Oct 29 14:24:55 UTC 2010:

Maybe I'll add a note for non-Slicehost users about that. We include aptitude in our Maverick images since as that link points out, aptitude is recommended over apt-get (and synaptic isn't really a good solution for most VPS users). Plus, as I understand it, the server version of Maverick still includes aptitude.

Nick Sergeant commented Mon Jan 31 03:08:53 UTC 2011:

I believe 'safe-upgrade' has also just been renamed 'upgrade' for 10.10 (or it least, 'safe-upgrade' has been removed).

Jered commented Mon Jan 31 21:31:25 UTC 2011:

Nick, I just tried on a fresh slice and safe-upgrade still works as an option to aptitude.

The "upgrade" option used to be the upgrade command in aptitude but it was deprecated in favor of "safe-upgrade" (which will update packages only if doing so doesn't require deleting other packages) and "full-upgrade" (which will update everything, deleting packages that conflict with updates). So while I see that maverick doesn't give you the message about "upgrade" being deprecated like you got with previous versions of Ubuntu and Debian, safe-upgrade still works and is still the best way to go.

Max Williams commented Sun Feb 13 22:30:58 UTC 2011:

Thanks for the great guide Jered. I'm using 10.04 rather than 10.10 (because 10.04 is the most recent LTS version at time of writing) and everything worked exactly as in the article (including 'safe-upgrade'). I'm now going to go and apply all the security steps to my other slice (for which i didn't read this guide while setting it up).

Justin L. Franks commented Tue Jul 12 22:52:22 UTC 2011:

If aptitude is not present on your system, you can simply run 'sudo apt-get install aptitude'.

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