Archive for Tutorials

How to restrict a specific package from installing (apt pinning)

17 Oct, 2010  No Comment

I tend to be very picky so there are a couple of packages which I do not want installed on my machines:

  • msttcorefonts: the Microsoft-like fonts. If you have those installed, Firefox will use them and you will get ugly windows-like font on most websites which I personally hate.
  • wine: Application to run windows programs on linux. For security reasons.
  • postfix: a mail server. Just because I do not want to run a mail server on my netbook.
  • ...and some other

The best way to restrict those packages from being installed is through Apt Pinning.

Apt pinning

It is very easy to pin packages and restrict them from being installed.
You will need to edit /etc/apt/preferences and add something like this:

Package: msttcorefonts
Pin: version  0.0
Pin-Priority: -1
 
Package: ttf-liberation
Pin: version  0.0
Pin-Priority: -1
 
Package: ttf-mscorefonts-installer
Pin: version  0.0
Pin-Priority: -1
 
Package: wine
Pin: version  0.0
Pin-Priority: -1
 
Package: postfix
Pin: version  0.0
Pin-Priority: -1

Pin-Priority: -1 restricts the given version from being installed, and the version 0.0 does not exist and should be a lower version than any versions of the given packages. As a conclusion, they will never be installed.

Be careful what you pin, though, as you might be too restrictive and could prevent installing or upgrading other useful packages.

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How to create a simple approval queue with Request Tracker (RT) 3.8

21 Aug, 2010  3 Comments

Introduction

In this post I will show how to create a simple approval queue in Request Tracker 3.8.

Request Tracker

The General queue will be used as the approval queue.

Here are the different entities (groups) we will create:

  • Submitters: they can submit new tickets only to the General Queue.
  • Approvers: they can approve tickets (move them from the general queue to another queue)

I will also show how to add a new dashlet ("RT at a glance") containing all the tickets the user created ("My issues").

Read the rest of this entry »

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How to set up Expires header with Apache2 on Ubuntu Lucid 10.04

27 Jul, 2010  2 Comments

A very good way to reduce page load time on your website is to tell your visitors' browser it can cache some specific files and save a copy on the disk.
This process is done by your web-server which is sending an Expires header and a max-age header during the HTTP response, e.g.:

200 OK
Cache-Control: max-age=604800
Connection: close
Date: Tue, 27 Jul 2010 22:31:03 GMT
Accept-Ranges: bytes
ETag: "2c956-376b-4696cb8b385c0"
Server: Apache/2.2.14 (Ubuntu)
Content-Length: 14187
Content-Type: image/gif
Expires: Tue, 03 Aug 2010 22:31:03 GMT
Last-Modified: Fri, 08 May 2009 20:46:23 GMT
Client-Date: Tue, 27 Jul 2010 22:31:02 GMT
Client-Peer: 127.217.30.5:80
Client-Response-Num: 1

Apache2 offers this feature through its mod_expires module. Note that this module is usually disabled by default, meaning your visitors would download all the files over again each time they change the page.

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Things to remember to backup or copy when migrating servers

10 Jul, 2010  1 Comment

A new version of your operating system just got released and you want to have a fresh new install, or you want to migrate all of your data to another machine. There are so much stuff to backup that you don't even know where to start?
I will try to list the most common stuff (on a web-server) to backup or copy somewhere when you want to do a server migration.

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