The Perl Ironman Challenge

Ironman Challenge. An effort to promote Perl within its community.

Accidentally stumble upon the challenge while searching for Perl's mailing lists and blogs.

I have always wanted to pick up a programming language. To buck up my system administration skill by scripting daily routines and system monitoring. And most importantly, write some web application with this much fascinated programming language that is well known for its TMTOWTDI (There's more than one way to do it !!!) flexibility.

This is my first post on the Ironman Challenge.

Why did I pick up the Challenge? A way to force myself to document what i have learn and also reminder myself to practice more. 1 post every week but no more then 10 days in between. I'll have to cough up with something i've learn, and i must learn. :p

At the same time, hopefully someone can spot what i have been missing or did wrong during my learning process. All constructive comments and suggestion is much appreciated.

Currently, i am working on converting the bash scripts i have, to perl. Reason to do so is getting a chance to familiarize myself with perl, with a goal. With this purpose, at least i don't bang around like a headless fly. Also, i think my bash scripts are some fast & dirty approach to accomplish things, which i think "use strict;" & "use warnings;" can fix/correct most of it. After a few days or so meddling around, manage to try out some condition & loop statements, date/time functions, database connections modules & some array operations. Huh, this is one topic for blogging.

At this stage, I am still trying to get around the documentation, perldoc. Most of the time, i'll be browsing "perldoc perltoc" to find out which functions and/or modules i can use. Still trying to figure out how to search for modules or functions.

CPAN. Comprehensive Perl Archive Network. There's definitely something for me to use, so that i don't have to "re-invent" the wheel. This is another nature of me, laziness. Re-using other people's code not only fulfill my laziness, but also make me write shorter code to accomplish my task.

The next post i will be talking about how to install & use modules.

That's all for now...

Adios !!!

BIND - name server error "the working directory is not writable"

Recently, there has been a few incident on vulnerabilities of DNS server being exploited. Fortunately, Bind have release patches soon enough for the rest of us to start covering up the loop holes.

After an upgrade or installations of ISC Bind DNS server 9.6 on a FreeBSD box, we will need to stop and start "named" service. As usual, running the below command will restart it :

/etc/rc.d/named stop
/etc/rc.d/named start

During the restart of the service, a few lines of text pops up saying that the permission of some directories in "/var/named" was altered. By default, the named files will need to be owner and group of "bind" in order for it to run properly. But the script in "/etc/rc.d/named" seems to change some directories ownership to "root" and group ownership to "wheel". This actually causes some errors reported in the log file :

Sep  3 02:44:26 nameserver named[9999]: the working directory is not writable

Naturally, we would issued the command :

chown -R bind:bind /var/name/etc

to fix the permission problem. But after another restart of "named" service using the command :

/etc/rc.d/named restart

the permission revert back to "root" and "wheel". This causes problem when the DNS server transfer zone files from the Master DNS server. The "named" service would not be able to write the latest zone info into the file in the directories "/var/named", then it would create some temporary files.

After some investigation, it seems like the ownership define in "/etc/mtree/BIND.chroot.dist" was set in this way. We will need to redefine the ownership of the directories so that it stop changing the directories ownership back to "root" whenever the "named" service is started so that "named" service owner, "bind" user, which runs the DNS server will be able to write the zones files in "/var/named".

Technorati blog claim fail error

This post is to record how to claim your blog in Technorati. The instruction received was to create a post with the codes provided then the claim process should complete. But it does not. The error below was showed when checking the status :

There was a problem finding your claim code.
If you have already verified above, please contact Technorati support with the following information :

* Please include the following error code: 400
* URL you are claiming : http://scratching.psybermonkey.net
* The name of your blog : Scratching My Needs
* Your contact info : myself@psybermonkey.net
* A short description of your blog and the type of content you like to write about. : This blog is all about Open Source, specifically about Freebsd, Linux and Perl.
* Does your blog have a RSS feed? Please see if you can supply us with an example URL of your feed. : Yes, the url is http://feeds2.feedburner.com/ScratchingMyNeeds

The instruction given from technorati when the codes was provided, did not work. There is a alternative way to claim the blog. That is, create a link on the post with the below html example :

<a href="http://technorati.com/claim/<the blog claim codes>" rel="me">Technorati Profile</a>

Which the "the blog claim codes" is the codes from Technorati, without the angle brackets (<>).

e.g.

<a href="http://technorati.com/claim/abc123xyx" rel="me">Technorati Profile</a>

Technorati should correct its instruction on how to claim the blog. Also, the support should actually buck up. If there wasn't any human(s) behind the support link, don't even put it up there. This confusion wasted 1 week of my time trying all kinds of post with the codes and figuring why the process does not work. Technorati, are you hearing???

FreeBSD - How to use Meta Ports to install group of ports

Often, after a fresh new installation of FreeBSD, we have a set of programs we want to install. The conventional method would be installing it one by one in /usr/ports. Today, we will use meta ports to install the set of applications by just one "make install clean" rather then "cd" into individual directories and do "make install clean" for every ports.

Meta ports are, as the name implies, ports file that describe about the program we are installing. The ports file describe where & what to install for this ports to work. A sample of "where" would be "where to download the source", "where to install it" and so on. As for "what", it would be "what to install to fulfill the dependencies". In this post, we will take advantage of this "what". We will define the dependencies as the list of programs we want to install so that the ports will install it.

This is an example of how to do it :

Apache - [warn] _default_ VirtualHost overlap on port 80, the first has precedence

Virtual Host. A feature that enables Apache to configure multiple domain into one web (http) server. This feature saves the need to run multiple instances of web server and thus saves resources.

After configuring the <VirtualHost> directives, some may encounter an error message :

Error : [warn] _default_ VirtualHost overlap on port 80, the first has precedence

This is due to the missing of a parameter, before any <VirtualHost> directives:

NameVirtualHost

MySQL - Passwordless login within bash script

As like the previous post about passwordless login within Bash script, this post is about how to connect to MySQL database server using Bash script without MySQL client prompting for login.

Here it is :

ssh - How to encrypt/tunnel internet traffic through ssh

When using an insecure internet connection (e.g. wireless), it is a good practice to tunnel internet traffic through ssh. Tunneling through ssh provide encryption of the traffic starting from local computer to the point ends where ssh server is. It is especially important to encrypt the traffic out of the local PC when using un-secure connection as other malicious intent users might be able to sniff packet off the current connection.

How does ssh tunneling works?

SmokePing - How setup logging (or debuging)

SmokePing is an utility to keep track of the network latency from your network to various site. Its output are recorded in graph, for analysis purpose. Its configuration are simple and easy to setup. But some times, logging are needed to debug some probes failed to output to graph. The logging setup will need to edit some files to make sure it rotate itself and syslog needs to be notified.

Here is how you get your hands dirty :

WordPress - wp-cache plugin not working

WordPress plugin wp-cache is a plugin that caches the WordPress post the first time when someone visits it then it uses the cache next time when the same post needs to load again. This saves processing power and also improves user experience as WordPress posts are loaded faster.

For some reason, wp-cache stop working. The "Cache contents" in WP-Cache Manager (accessible from Settings --> WP-Cache) shows both "cached pages" and "expired pages" are "0" (zero) all the time.

The fix is :

FreeBSD - Quick install guide (aka How to install FreeBSD)

Much great have been said on FreeBSD;

• the license has all the freedom you need
• server apps setup are mostly manual. no wizard of oz, no gui. Which makes the administrator have control over everything.
• it boots faster
• its stability is like rock, hard to crash :)
• default installation are lean and mean. Is meant to be built from scratch. Ain't no rubbish you want on the system to trade for vulnerabilities.

Even though some of the above might scare off a normal user, no doubt it is still a great OS that no others can beat. Don't believe me? Try it yourself with the below few pictures (to guide) :

Linux - Shorewall firewall with PPTP VPN dialup client

PPTP VPN uses protocol GRE on two way, both inbound and outbound. Setting up the firewall to allow PPTP VPN dialup client (e.g. Ubuntu's NetworkManager) to use protocol GRE is just a few steps in adding rules and interfaces. This post is based on the previous post "How to set up Shorewall firewall (alternate to FireStarter)", which is a quick tutorial on setting up Shorewall firewall on a single network interface. Here it is :

Linux - How to set up Shorewall firewall (alternate to FireStarter)

There are a few option of firewall interface available on Linux for iptables, both GUI (Graphical User Interface) and CLI (Command Line Interface). FireStarter user interface on GUI is easy to use and configure. The only problem is it does not work properly with PPTP VPN dialup, it blocks protocol GRE. It does provide a workaround (dont ask, it is too painful to remember) but the steps are too tedious and involve the mixture of setup in command line and GUI, and this kind of setup always spells trouble.

Shorewall is another firewall interface that operate on CLI. This is taken from the Shorewall's introduction :

"The Shoreline Firewall, more commonly known as “Shorewall”, is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables, iptables-restore, ip and tc utilities, Shorewall configures Netfilter and the Linux networking subsystem to match your requirements. Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode and can thus take advantage of Netfilter's connection state tracking capabilities."

Shorewall's way of configuring iptables firewall made easy by just describing the rules and interfaces into a few files and the firewall is ready to go. Shorewall's website also provides extensive documentation on how it works and how to setup.

This post's intended to setup Shorewall in a few simple steps and thus, it is not really suitable to implement it on medium to large enterprise. Here it is :

FreeBSD - Error installing KDE4 or Xine

Halfway through installing KDE4 or any ports that is related to Xine, ended fail with the below error message :

===>  Found saved configuration for libxine-1.1.16.3_1
=> xine-lib-1.1.16.3.tar.bz2 doesn't seem to exist in /usr/ports/distfiles/.
=> Attempting to fetch from http://superb-east.dl.sourceforge.net/sourceforge/xine/.
xine-lib-1.1.16.3.tar.bz2                     100% of 7293 kB  232 kBps 00m00s
===>  Extracting for libxine-1.1.16.3_1
=> MD5 Checksum OK for xine-lib-1.1.16.3.tar.bz2.
=> SHA256 Checksum OK for xine-lib-1.1.16.3.tar.bz2.
===>   libxine-1.1.16.3_1 depends on file: /usr/local/bin/perl5.8.9 - found
===>  Patching for libxine-1.1.16.3_1
===>   libxine-1.1.16.3_1 depends on file: /usr/local/bin/perl5.8.9 - found
===>  Applying FreeBSD patches for libxine-1.1.16.3_1
1 out of 1 hunks failed--saving rejects to src/combined/ffmpeg/Makefile.in.rej
=> Patch patch-src_combined_ffmpeg_Makefile.in failed to apply cleanly.
=> Patch(es) patch-config.rpath patch-configure patch-misc_Makefile.in patch-misc_libxine.pc.in patch-src:libffmpeg:libavcodec:h263.c patch-src:libffmpeg:libavcodec:mpeg12.c patch-src:libffmpeg:libavcodec:msmpeg4.c patch-src:xine-engine:xine_internal.h patch-src_audio_out_audio_oss_out.c applied cleanly.
*** Error code 1

Stop in /usr/ports/multimedia/libxine.
*** Error code 1

It seems that the patching for ffmpeg in libxine fail for some reason. Checking out the freebsd.org bugs database, it is due to ffmpeg in libxine does not need that patch. The solution to it is :

Ubuntu - How to resume NetworkManager managing network interface

After manually editing /etc/network/interfaces for dynamically assigned IP or static IP, Network Manager (the icon sits on the upper panel with 2 monitor) stops working. Specifically it stop managing interface, but manually assigning IP through "ifconfig" or editing config files (/etc/network/interfaces) still works. Another reason NetworkManager stop working is after applying some updates between Intrepid (8.10) to Jaunty (9.04) it just stop working. Here is the solution :

FreeBSD - How to install flash plugin or player to work with FireFox

This post is part of the "How to install FreeBSD as your Desktop" series and it shows how to install flash plugin onto FireFox internet browser in FreeBSD. Here it is :

Freebsd - How to install FreeBSD as your Desktop

UPDATE : After testing PC-BSD for a while (more then 6 months), PC-BSD indeed is a FreeBSD variant that is superior in Desktop environment. Its user friendly installation and configuration have make FreeBSD so much more suitable running as an Desktop. Unless you're interested in figuring out how to tweak and turn FreeBSD to work in a Desktop, give PC-BSD a try, you'll love it!
Check it out at PC-BSD website !!!

PsyberMonkey is turning his desktop to FreeBSD and this is the work he has done :-

1. FreeBSD quick install guide (aka How to install FreeBSD).

2. make sure hardware are detected properly

• How to install or add sound card driver module
• wireless (how to still in progress)
• ACPI (still having trouble making it work)
• remote control through SSH (how to still in progress)
• all others e.g. external drive formatted in FAT32, display card, track pad, external mouse, gigabit network card & etc are detected and function properly.

3. Using ports to install software - go to Section III.

4. Getting KDE, GNOME and XFCE up and running (how to still in progress)
Other miscellaneous stuff :

• How to disable or turn off the keyboard beep sound
• How to assign or remove fixed IP
• IP address automatically assign aka DHCP
• How to install flash plugin or player to work with FireFox
• Backup & restore for disaster recovery
• How to upgrade the kernel or base system
• Error installing KDE4 or Xine

This post will be updated periodically to reflect the progress of using FreeBSD as a Desktop.

Adios !!!

FreeBSD - How to disable or turn off the keyboard beep sound

A reminder to myself on how to disable the keyboard beep sound (serve as an alert) when ever an error occured in the console command line. It is control by a sysctl value. To stop it now on all console, execute :

sysctl hw.syscons.bell=0

To make it permanent, such as every time FreeBSD boots, disable the beep sound :

echo "hw.syscons.bell=0" >> /etc/sysctl.conf

Alternately, to disable only this console :

kbdcontrol -b off

Vaarwel !!!

Freebsd - How to install or add sound card driver module

FreeBSD is getting more and more attention due to its stability and (well done) documentation. Geeks and nerds are getting their hands into installing FreeBSD onto their Desktop or Laptop.  Some might ask "Eh ??? Why ain't ya mentioning the servers? Is BSD.". Sound card, sound card belongs to multimedia. It's mostly meant for entertainment so it's gonna stay on the "personal" thing. e.g. Personal Computer, laptop, notebook, rig, moo or whatever you called it. :p

Back to the topic. This post will try to demo on how to install sound card driver onto FreeBSD.

FreeBSD - How to upgrade the kernel or base system

The nature of FreeBSD is so rock-solid stable that some system administrator adopt the philosophy "if it ain't broken, don't fix it", others, beg to differ. Upgrading & patching of servers should be diligently carry out so that security vulnerabilities are minimize to the least (who can be sure of their servers are 100% secure ???), introduce to new application features (which geek doesn't like new stuff ???) & performance increase (meaner & leaner :) ). Patching can only be done to a certain level then it will need kernel and base system to compile and build the latest patches or upgrades.

Regular upgrade of the FreeBSD kernel and base system is a good way to follow the support schedule. It would mean that your server would have a longer life span in the production. Not because of some latest OS "GUI" release that demand higher RAM for the "processor hungry monster" lies beneath the OS "GUI" release. But rather, it fixes the bugs of the applications, gives you more new functions and make your hardware works harder & faster.

There are some hiccups to take note of. As with all OS upgrade, the will experience up time interruption (aka server down time) . Scenario such as :

:- The performance of the server have greatly draw by the upgrade process and impact the usual services the server runs. Thus the response time of the server fail to serve the users in time and affected the normal operation of the business.

:- The upgrades break the kernel or base system and the server fail to boot.

:- After the first boot up of the upgrade, the applications fail to compile properly and resulted the services fail to start.

:- The is your first FreeBSD upgrade and you can't predict what would happen and hiccups just like to happen at these times. :p

All of the above can be avoided as long as the below points are observe :

• plan and schedule the upgrade with adequate time so that even hiccups happen, there are ample time to solve it.
• plan a trial server upgrade or mock run of the upgrade to anticipate what hiccups might happen and test the solutions. Use the server backup and restore to another hardware, virtual machine or sandbox to test the server upgrade. Drop down every step and retry it if time permits to minimize the hiccups.
• The is the most important one. Always backup/restore perform a full system backup with no less then 1 day of difference. The shorter time of the difference between the backup and the upgrade, the faster and painless the restore process is. This also mean shorter down time.

Freebsd - Backup & restore for disaster recovery

Data are all around servers.. To name a few, file server, email server, LDAP server, web server, DNS server and these are just a few essential servers that make up part of IT section of your company. ERP, CRM, financial projection system, database server, accounting & payroll system are the example of business application. Imagine, what if "some" of these data are loss. It is also worth mentioning that data is so valuable to the company, that partial loss of it might lead to breaking your business continuity !!!

Most of the company operation are depending on these data in the server to make decisions. Data in the servers have never been so important.

Server data disaster recovery planing is a vital process in system administration. It directly shows how much the system administrators understand the importance their role in the business. Reason for data loss can be classified into 2 main categories, natural disaster and man made disaster. Natural disaster that causes data loss includes flood, earthquake, fire hazard and etc. Man made disaster (aka PBKC which denodes Problem Between Keyboard and Chair :p ) examples, hacking activities, accidental data deletion or over written and server maintenance e.g. patching, upgrades, developments, moving to a bigger size of hard disk & etc.

Disaster recovery involves planning, backup & restore. Planning will need identify which are the crucial data to backup and how frequent should it be backup. The next consideration will be what media should the data be save to. Generally, external hard disk (e.g USB) or network based storage (e.g. file server, ssh server, NAS, SAN) are the cheapest & fastest way to store the data. But if the data is to archive, it should go into media e.g. tape, CD, DVD and other optical media. Lastly, all planning and backup of the data should always test against restoration, or else why even plan to save it. :)

This post will concentrate on how to prepare for Server disaster recovery on a FreeBSD server. Do take note Database backup is not cover in this post as Database backup itself, have already a few strategy to look on.

There is an update for this post, please check out the updated post "FreeBSD – Backup and restore FreeBSD using Fixit CD".