Sid Sidberry Reads

I ran across this tut this morning while doing research for my at home setup. Pretty straight forward, so I’m sharing for yours and my reference.

In this chapter we will work through steps involved in installing and running Windows XP and Windows Vista as virtualized Xen HVM guests.

Pre-Requisites for Installing a Windows Xen Guest

This chapter assumes that the Xen host (domain0) system is running a Xen enabled kernel and that the standard Xen tools (specifically xm) are also installed. In addition, full virtualization requires that the host system hardware include either Intel-VT or AMD-V virtualization support. In order to verify this run the following commands on the host system:

For Intel CPUs:

grep vmx /proc/cpuinfo

For AMD CPUSs:

grep svm /proc/cpuinfo

If neither of the above command produce output then it is likely these features are unavailable and that your hardware is unable to run Xen HVM guests. Whilst you can still run modified operating systems (such as Linux) as paravirtualized guests you will not be able to virtualize Windows using Xen. It is also possible that the host CPU supports one of these features, but that the functionality is disabled by default in the system BIOS. To verify this, access the host system’s BIOS configuration menu during the boot process and look for an option related to virtualization support. If such an option exists and is disabled, enable it, boot the system and repeat the above commands.

Preparing to Install Windows

In order to install Windows as a Xen HVM guest the first requirement is disk space. The space assigned to a Windows guest may be either a physical disk drive attached to the host system or a disk image. To create a disk image simply use the dd command. For example, the following command line created a 6Gb disk image file called xenwin.img:

dd if=/dev/zero of=xenwin.img bs=1024k seek=6144 count=0

Preparing the Windows XP / Windows Vista for Xen HVM Installation

Installation will require a Windows XP or Vista installation DVD. Installation may be performed directly from the DVD drive, or the DVD image may be extracted from the DVD to an ISO image residing on the filesystem of the host. To extract the ISO image from the DVD insert it into a DVD drive, unmount it if it is auto-mounted and execute the following command (substituting /dev/hdb for the matching device on your chosen Linux distribution):

dd if=/dev/hdb of=Windows.iso

Once the copy is completed the DVD can be removed from the drive and stored safely, and the Windows.iso file used to perform the installation.

[edit] Configuring the Xen Windows Guest Configuration File

Once the disk or disk image is available the next step is to create a suitable Xen HVM configuration file. The following lines are standard and should be used unchanged for all HVM configurations:

import os, re
arch = os.uname()[4]
if re.search('64', arch):
    arch_libdir = 'lib64'
else:
    arch_libdir = 'lib'

kernel = "/usr/lib/xen/boot/hvmloader"

builder='hvm'

Next the amount of memory to be assigned to the Windows XP or Windows Vista guest needs to be declared, in this case 512Mb:

memory = 512

Next, the amount of shadow memory may be defined. This should be equal to 2KB per MB of domain memory, plus a few MB per vcpu. In general 8Mb is sufficient:

shadow_memory = 8

The domain name and networking choices now need to be made. If you wish to bridge to the networking device on the host system use the following vif setting:

name = "xenhvm"

vif = [ 'type=ioemu, bridge=xenbr0' ]

Now, the most important part of the configuration is to specify the disk and CD/DVD settings. If a physical disk and CD/DVD drive are to be used this setting will read something like:

disk = [ 'phy:/dev/sdb,hda,w', 'phy:/dev/hdb,hdc:cdrom,r' ]

The above line maps physical disk drive /dev/sdb on the host to /dev/hda on the guest and /dev/hdc on the host as the cdrom device on the guest (note that the CD/DVD device name on your host may be different depending on your Linux distribution).

Alternatively, if a disk image file is to be used as the disk drive the line might instead read:

disk = [ 'file:/home/xen/xenwin.img,hda,w', 'phy:/dev/hdb,hdc:cdrom,r' ]

Alternatively, if you have opted to use an ISO image of the Windows XP or Windows Vista installation DVD this can be referenced in place of the CD/DVD device:

disk = [ 'file:/home/xen/xenwin.img,hda,w', 'file:/home/xen/Windows.iso,hdc:cdrom,r' ]

Next the boot order of the guest needs to be defined. Clearly the CDROM device needs to be first in the boot order, at least until Windows is installed on the disk drive:

# boot on floppy (a), hard disk (c) or CD-ROM (d)
# default: hard disk, cd-rom, floppy
boot="dc"

Some configuration settings now need to be made to enable a graphical console for our Windows guest operating system. Xen provides a choice of VNC or SDL for supporting a graphical console when the guest is running. For example the following settings select VNC:

vnc = 1
sdl = 0

whilst the following selects SDL:

vnc = 0
sdl = 1

Both SDL and VNC work very well in terms of displaying Windows in a graphical console, although VNC has some distinct advantages over SDL. Firstly, VNC provides greater flexibility than SDL in terms of remote access to the domainU graphical console. With VNC it is possible to connect to the graphical console from other systems, either on the local network or even over the internet. Secondly, when you close a VNC viewer window the guest domain continues to run allowing you to simply reconnect to carry on where you left off. Closing an SDL window, however, immediately terminates the guest domainU system resulting in possible data loss.

By default Xen does not automatically start the VNC console when the domainU guest starts up. In order to have the graphical console spawned automatically, change the vncconsole = value to 1:

vncconsole=1

After selecting the graphical display options a number of other settings are required and/or recommended:

acpi = 1
apic = 1
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
stdvga=0
serial='pty'

One final setting is needed to avoid problems with the mouse pointer:

/read: Installing and running windows vista / xp as a Xen HVM DomU Guest

grep vmx /proc/cpuinfo

grep svm /proc/cpuinfo

dd if=/dev/zero of=xenwin.img bs=1024k seek=6144 count=0

dd if=/dev/hdb of=Windows.iso

import os, re
arch = os.uname()[4]
if re.search('64', arch):
    arch_libdir = 'lib64'
else:
    arch_libdir = 'lib'

kernel = "/usr/lib/xen/boot/hvmloader"

builder='hvm'

memory = 512

shadow_memory = 8

name = "xenhvm"

vif = [ 'type=ioemu, bridge=xenbr0' ]

disk = [ 'phy:/dev/sdb,hda,w', 'phy:/dev/hdb,hdc:cdrom,r' ]

disk = [ 'file:/home/xen/xenwin.img,hda,w', 'phy:/dev/hdb,hdc:cdrom,r' ]

disk = [ 'file:/home/xen/xenwin.img,hda,w', 'file:/home/xen/Windows.iso,hdc:cdrom,r' ]

# boot on floppy (a), hard disk (c) or CD-ROM (d)
# default: hard disk, cd-rom, floppy
boot="dc"

vnc = 1
sdl = 0

vnc = 0
sdl = 1

vncconsole=1

acpi = 1
apic = 1
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
stdvga=0
serial='pty'

usbdevice='tablet'

import os, re
arch = os.uname()[4]
if re.search('64', arch):
    arch_libdir = 'lib64'
else:
    arch_libdir = 'lib'

kernel = "/usr/lib/xen/boot/hvmloader"

builder='hvm'

memory = 512
shadow_memory = 8
name = "xenhvm"
vif = [ 'type=ioemu, bridge=xenbr0' ]
disk = [ 'file:/home/nas/xen/xenguest.img,hda,w', 'phy:/dev/hdb,hdc:cdrom,r' ]
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
# boot on floppy (a), hard disk (c) or CD-ROM (d)
# default: hard disk, cd-rom, floppy
boot="dc"

sdl=0
vnc=1
vncconsole=1
vncpasswd=''
stdvga=0
serial='pty'
usbdevice='tablet'

xm create xenwin.cfg
Using config file "./xenwin.cfg".
Started domain xenhvm

awesomely wicked

From: http://www.learningjquery.com/2008/10/1-awesome-way-to-avoid-the-not-so-excellent-flash-of-amazing-unstyled-content

This tutorial describes a way to avoid a flash of unstyled content that sometimes occurs when applying styles with JavaScript on page load. The problem is most evident when there is some content that needs to be hidden initially and when the document is large or complex. We can see an example of the problem on this test page.

The page is a copy of a previous entry on this blog with over 140 comments

I’ve been slowly working on moving all of my projects and tutorials to one site. Mainly because there treated like blog posts instead of projects. This of course lead me to start looking at which license to start looking at which license to release everything as.

After a few days pouring over everything on the web I decided to choose the mit license. Why? The mit license fits how I want to release my code. It releases my code openly to anyone, only asking that the copyright in my code remain.

This will probably lead to you ask why not gpl, apache, or bsd?

why I didn’t choose gpl

the gpl license [http://en.wikipedia.org/wiki/GNU_General_Public_License] is restrictive IMO, due to the fact that it forces a user to release anyone that uses what i create under gpl as well. This is not to say that the gpl is wrong, just that its restrictive to end users / developers in a way I choose not to me. If someone takes code that I am openly releasing, I don’t want to limit them in anyway other than to leave a portion giving me credit for my portion of code, that’s it.

If i was working on some huge next best thing (think wordpress) and planned to release it, then I would use a gpl license. why? something like wordpress could easily be exploited commercially. If I take the time to build something like that I would want anyone who decides to change it or build off of it to release it themselves, to also make sure it’s free under the same license. The biggest difference here is intent. If you were to create the next swfobject.js (which uses an mit license), why restrict your users? But if your creating the next wordpress you don’t want to restrict users, just ensure that your work continues to be free.

why i didn’t choose bsd

the bsd license is similar to the mit license, but with an advertising clause. So to prevent anyone from any legal issues (who knows what counts as advertising in the future), why restrict end users?

why I didn’t choose apache

the apache license is the default license for projects at google code (you can select others), so it’s gotta be good. But it feel slightly more restrictive. That said: I’m releasing anything that uses patents. If you are then an apache license might be for you if you’d like to not restrict users.

in a nutshell

I think the best quote I came across was from eagain.wordpress.com:

if you want software to be free GPL is better than BSD. If you want use of software to be free BSD is better.

I think mit/bsd licenses are better for developers when your creating random things that might help someone (think swfobject). gpl is better if your developing an application to help everyone (think wordpress).

sid

*update* – found another good article:

http://fosswire.com/2007/04/06/the-differences-between-the-gpl-lgpl-and-the-bsd/

From: http://www.barelyfitz.com/screencast/html-training/css/positioning/

This tutorial examines the different layout properties available in CSS: position:static, position:relative, position:absolute, and float.

Check It Out:
Learn CSS Positioning in Ten Steps: position static relative absolute float

So after 3-4 days of research and study I’m compiling a list of links that helped me finally understand couchdb. Still bunches to learn, but hopefully it will save others from 4 days of googling.

Start

The very first thing you should read is the work in progress online couchdb book:
Relax with CouchDB [http://books.couchdb.org/relax/]

Now that your started

The following sections are grouped by what I left the article better understanding. They may cover other areas, but then again more knowledge leads to better understanding right?

JSON

Just in case you don’t understand json:

http://webt.wordpress.com/2007/10/01/json/

Couch MapReduce

fyi: hashes

Depending on what language your coming from you may know hashes as arrays or associative arrays. When they say reduce returns a single value, they are referring to the hash value it returns (scratched my head for a while)

If your coming from php an easy way to connect the dots is to think of how serialize creates a string that represents your object. Only in couchDb this is a json string

I had my eureka moment here:

http://www.ibuildings.com/blog/archives/1291-Some-thoughts-on-CouchDB.html

Just in case you didn’t eureka:

http://rrees.wordpress.com/2008/03/09/couchdb-querying-data/

Damien Katz explains more on couch’s mapreduce ( check the part 2 near the end as well ):

http://damienkatz.net/2008/02/incremental_map.html

MapReduce Method

In case you didn’t know mapreduce isn’t something couch invented, you can learn more about mapreduce below.

explains the mapreduce method in detail:

http://code.google.com/edu/parallel/mapreduce-tutorial.html#MapReduce

the mapreduce white paper:

http://labs.google.com/papers/mapreduce.html

mapreduce lecture (didn’t watch, but it was recommended by google, so why not):

http://www.youtube.com/v/-vD6PUdf3Js

using couchdb

blog db example / couchdb “joins”:

http://www.cmlenz.net/archives/2007/10/couchdb-joins

user permissions system example / offers rdbms comparison:

http://kore-nordmann.de/blog/couchdb_a_use_case.html

aimee’s 8+ couchdb on rails series (links to part 1, but your good from there):

http://aimee.mychores.co.uk/2008/09/07/post/320/

couchdb internals

Ricy ho’s overview:

http://horicky.blogspot.com/2008/10/couchdb-implementation.html

Related discussion where btrees are further discussed (as well as some decent bantering):

http://www.reddit.com/r/programming/comments/792hf/couchdb_implementation/

Ayende Rahien has an indepth series on couch db called: reading erlang

http://ayende.com/Blog/archive/2008/09/24/reading-erlang-inspecting-couchdb.aspx

http://ayende.com/Blog/archive/2008/09/24/more-couchdb-reading-btreelookup.aspx

http://ayende.com/Blog/archive/2008/09/24/more-couchdb-reading-btreequery_modify.aspx

http://ayende.com/Blog/archive/2008/10/04/reading-erlang-couchdb-from-rest-to-disk-in-a.aspx

http://ayende.com/Blog/archive/2008/10/04/erlang-reading-couchdb-digging-down-to-disk.aspx

http://ayende.com/Blog/archive/2008/10/06/reading-eralng-couchdb-streams.aspx

The most important part

Use it damn it! get planning, hacking, pop locking and start playing with couch

sources

Sources not referenced already:

http://damienkatz.net/2008/09/peek_into_couchdb.html

http://jan.prima.de/plok/

While continuing my trolling for all things couchdb, I came across this tutorial. Christopher Lenz uses a blogging system to explain how a couchdb database could be setup and how to perform a join (or something similar). Better yet the reccomended join method comes from the couchdb creator himself

From: http://www.cmlenz.net/archives/2007/10/couchdb-joins

I’ve been playing more and more with CouchDB lately. After putting together a Python library, I worked on a brand new included HTML/AJAX interface. Now I’m starting to dive into the Erlang code, which is my first serious encounter with Erlang. In particular, I started a branch that aims to replace the HTTP server underpinnings with Bob Ippolito´s not-quite-released-yet Mochiweb library.

Despite all that activity (and past experience with the conceptually similar Lotus Notes), the correct approach to designing applications “the CouchDB way” isn’t always obvious to me at this point. Just today, there was a discussion on IRC how you’d go about modeling a simple blogging system with “post” and “comment” entities, where any blog post might have N comments. If you’d be using an SQL database, you’d obviously have two tables with foreign keys and you’d be using joins. (At least until you needed to add some denormalization.)

But what would the “obvious” approach in CouchDB look like?

Check It Out:
about:cmlenz – CouchDB “Joins”

So after about 2 months on slicehost, I have yet to finish setting up my server. It seems to be the busy season and I’ve only been able to finish my local servers.

So to recap I know have a media temple box and a slicehost box. Now to further complicate the situation after much debate / research I’m looking at linode: http://www.linode.com.

Why linode?

1. They use Intel processors
2. More ram, space, bandwidth
3. better control panel
4. better vps management

That said slicehost has been great for information. I’m not a fan of their forums but they do have great tutorials.

Why slicehost?

1. They seem slightly more stable
2. Made by developers for developers
3. First impressions

…. so that said, sorry for the lack of new tutorials, code, broken templates, etc

And now to see about canceling one of these damn server

Ok so in the last 2 weeks I’ve written 3-4 ffmpeg installation tutorials (centos, ubuntu, source, ffmpeg-php). Yes I know I haven’t posted any of them. Today I ran across this

http://www.sherin.in/ffmpeg/index.php?option=com_content&task=view&id=14&Itemid=1

Guess that that link goes to? Yeap an auto installer that installs ffmpeg and ffmpeg-php. So basicly all the searching I’ve had to do to find dependencies, bug fixes, spefic distor packages, etc: was pointless

I’ve tested this on centos 5, ubuntu 7.10, and will test on openSuse shortly.

ffmpeg / ffmpeg-php installer:

http://www.sherin.in/ffmpeg/index.php?option=com_content&task=view&id=14&Itemid=1

Sid

Jim Plush has written a pretty decent overview of php’s bitwise functions. My only complaint is I wish he’d also used even numbers so readers could understand flag systems, but you can’t win them all

As an added bonus, he’s included a comic that explains binary counting in a way you’ll never forget ( If only all teachers taught this method )

PHP Bitwise Tutorial by Jim Plush

Before you start

Before starting anything you should be sure that you have the developer tools package installed. If your not sure, then you don’t. No worries: submit a request to install the developer tools package and you’ll be ready in about 45min to a hour.

Get started

first login as root

next download electroserver:

wget http://www.electro-server.com/downloads/builds/ElectroServer_4_0_4_linux.rpm

next install the rpm:

rpm -iv ElectroServer_4_0_4_linux.rpm

You should now have a /opt/ElectroServer_4_0_4/ directory. browse around it and we’ll continue from there.

I had no issues up to this point, but feel free to post any problems and I’ll try to help.

Testing the install

in the /opt/ElectroServer_4_0_4/ you’ll notice a few files. to test your install run the ElectroServer command

If your lucky you’ll have no errors or issues getting the server running. I encountered an issue related to memory available. a quick reboot of the server fixed this.

Configuring the server

For this tutorial we’ll use port 8080 for the web admin, and port 9898 for our chat server. if you need to use other ports just follow along. you can also repeat this process to enable additional ports.

we’ll need to enable access to port 8080 and 9898. port 8080 will be used for the web admin, port 9898 will be used for the text (chat) connection.

to open your ports run the following:

port 8080

/sbin/iptables -A INPUT -p tcp --dport 8080 -j ACCEPT
/sbin/iptables -A OUTPUT -p tcp --dport 8080 -j ACCEPT

port 9898

/sbin/iptables -A INPUT -p tcp --dport 9898 -j ACCEPT
/sbin/iptables -A OUTPUT -p tcp --dport 9898 -j ACCEPT 

next edit your ES4Configuration.xml which can be found at: <install directory>/server/config. if your following this tutorial on a media temple dv server this directory is /opt/ElectroServer_4_0_4/server/config/ES4Configuration.xml

ES4Configuration.xml your default configuration should look like this:

<?xml version=”1.0″ encoding=”UTF-8″ standalone=”no”?><ElectroServerConfiguration>

<!– This is the name of the node –>
<Name>StandAlone</Name>

<!– Defines the host and port on which the web server will listen for inbound connections –>
<WebListeners>
<WebListener>
<Host>127.0.0.1</Host>
<Port>8080</Port>
<Ssl enabled=”true”/>
</WebListener>
</WebListeners>

</ElectroServerConfiguration>

to get our server live we’ll need to give it an ip address, change 127.0.0.1 to an ip that is live on your server

Getting the server running and listening

before we can actually test our install we need to make sure that we’ve placed a crossdomain.xml at the root of the website listening at the ip used. if the ip is shared place the crossdomain file in the root of the default domain. the crossdomain.xml should be viewable at http://<electroserver ip>/crossdomain.xml, replace <electroserver ip> with the ip used in your ES4Configuration.xml.

be sure that you create allows for your running host, and any other domains that will access the server.

now restart electroserver if its already running and test if electroserver is excepting connections using telnet.

test that electroserver is running and able to listen by running telnet <electroserver ip> 8080

telnet should successfully connect. if not try shutting down all electroserver processes and start electroserver again. we’re now ready to get moving with getting our chat server running.

Use electroserver admin

the configuration used in this guide uses ssl, if your not using it then remember to use http where the guide says https.

access admin at https://<electroserver ip>:8080/admin

default user name: administrator
default password: password

once logged in go to gateways and edit the default gateway. change 127.0.0.1 to <electroserver ip>, save and restart the gateway

Test Chat Access

Electroserver by default runs chat on port 9898. restart electroserver and telnet to your electroserver ip, this time testing port 9898. your should recieve the contents of your crossdomain file as a response.

Almost Done

we’ll also need to add electroserver to our server startup. First create a file named: StartElectroServer, next  add the following to that file:

/usr/bin/nohup /usr/local/bin/ElectroServer &
exit

Place the script in you opt/electroserver directory with read and execute permissions. Now the final step link your file so it’s called at startup

ln -s /opt/ElectroServer_4_0_4/StartElectroServer /etc/rc.d/init.d/StartElectroServer

thats it, you should now be all set to run electro server.

Also to run electroserver without it closing when your console closes use: nohup ElectroServer &

Got questions? post a comment, or just post a comment to let me know this was helpful.

Sid