To much to my surprise as soon as I plugged the printer Ubuntu recognized the printer and installed it, with in few seconds without any clicks or key presses the printer was ready for printing. I never bothered testing on Windows 7 but I’m sure I would have had to install drivers (Samsung claims it takes only 4 clicks).

However I ran to some trouble sharing the printer with Snow Leopard as the driver selected by Ubuntu needed to be used as a raw printer queue and I could get around how to set it up on Snow Leopard. Instead I flipped around the setup, I shared the printer as a raw printer queue and used the built in driver on Snow Leopard for the printer. I had to do the same for my notebook as well. Everything was working perfectly, finally . In the process I also figured out that Generic GDI driver works as long as the print job fits the printer memory (8 MB), if you send a larger job it will fail with nothing printed (but the printer receives the job).

For anyone wondering, on Linux the driver used is (automatically selected by Ubuntu) is Samsung ML-1640, SpliX V. 2.0.0 , which covers all capabilities of the printer (may be except for toner level).

I’m really happy with the printer, I think it was a very good purchase. I really like the idea the cartridge comes with a handle to push it into place. Then the fact that I can print the demo page by pressing and holding the reset/cancel button on the printer to get the toner level and other printer details. Only thing I miss is fully duplex printing, but with the lower cost I don’t mind working upto the printer to feed the paper when the printer is done printing one side of the pages.

On Thursday (29th July), an update to iKeyword was released enabling users fetch unlimited number of related keywords based on user feedback upping the version to 1.0.2 from 1.0.1 . If the number of related keywords returned was an issue that prevented you from using iKeyword; download to iKeyword 1.0.2 now on the iPhone App Store.

Whole of this week I have been working on an uber cool iPad application which will hopefully be released in August, it’s a biggie. Stay subscribed or follow me on Twitter to be the first to hear when it’s released.

Btw, system administrator appreciation day falls tomorrow; do not forget to throw a party for your SysAdmin, get him/her a gift or just say thanks

For everyone’s benefit;

1. Power up your PC or Mac
2. Open iTunes
3. Goto iTunes store home (Click the home icon once you get to iTunes store)
4. Click “Redeem” under “Quick links” (highlighted in the screenshot above)
5. Key in the redeem code and click the Redeem button

Enjoy your app free app

To much to my surprise Apple’s approval process only took 7 days (5 working days), thank you Apple for speedy approval . See the screenshot of iTunes Connect bellow.

Then the familiar Mobile partner will open up, and follow the instructions on the screen.

Hope this helped someone in a similar situation

direct-marketing.biz
Page rank 3 domain with a generic term. Rare opportunity no direct marketing firm should let go.

iaews.biz and iaews.us
Pair of page rank 7 domains. Not sure what iaews stands for but I’m sure what ever you host will make to the top of the Google index fast. Great SEO value.

meridianhealthcare.us
Page rank 5 domain. Great for a US based health care firm. If you are lucky New Jersey based Meridian Health will definitely be interested in this domain. Great opportunity for an experienced domainer.

Send me your offers, these domains are going fast as I need the cash fast to improve R2G Tools and I’m not very good at hard selling

What’s behind

Database; MongoDB is the main database backend, with MySQL used to hold non domain records. MongoDB was chosen because of it’s ability to handle large amount of objects, schemaless and ability to index keys. Thanks to MongoDB I can search, count and even insert and update records in few seconds (most operations are few milliseconds).

Web application framework; whois.r2g.in is completely built with CodeIgniter. It’s my framework of choice. I like it’s clean and lean architecture.

Servers; I’m running Lighty behind Varnish HTTP accelerator. I also use eaccelerator to optimize PHP code. I also have a memcached instance on the web server to cache data from MySQL. Goal is to speed up whois.r2g.in as much as possible. There are 2 MongoDB instances sharing the load which the application connects. Everything is running off 3 Athlon X2 servers, 2 running MongoDB instances and one running the application.

Why use both MongoDB and MySQL?

That’s because I didn’t want to put all my eggs in one basket. Any data that doesn’t change much like WHOIS servers put into a MySQL table. Information such at WHOIS data were stored in a MongoDB collection.

What I gained?

Lot of experience about data mining, storing and analyzing. I learned a lot about how to optimize data mining, I managed to bring down the time it takes to analyze all the domains for drops to few hours from few days by just pre sorting the zone files. I also gained few rare domains and high page rank domains. I have become a domainer thanks to the project

Please head over to R2G Tools and give it a try,  you might discover a great domain while you are there and make a huge profit. Do not forget to send me some feed back

1. Connect the iPhone or iPod Touch to your Mac or PC
2. Click on the device in iTunes, go to the “Summary” tab, click on the “Serial Number” label. The “Serial Number” will change to “Identifier”
3. Click on “Edit” in the menu at the top and select “Copy”
4. Now you can paste the device ID into an e-mail

Hope this helps if you don’t have access to a Mac or XCode and need to find out the device ID.

Was waiting for 5 minutes still stuck in the grey screen

If it doesn’t boot in reasonable amount of time, please boot in verbose mode. Press F8 to enter start up options and provide the option -v to boot in verbose mode. If you get a no entry sign or ask you to reboot, you are probably out of luck, still reboot and see whether your luck changes

Customize the installation

It’s important to select the correct drivers and other patches for the installation to work properly. In my case I had to select the following:

• Video Driver: NVInject 512MB
• OSx386 tools

If you are using PS/2 keyboard and mouse you will have to install the PS/2 patch. I’m not sure how well this will work as I have USB keyboard and mouse.

Here are some “screen shots” while installing. Please bear with the quality, I’m a horrible photographer

Mount the image in read write mode

$ hdiutil mount iPC_OSx86_10.5.6.iso -readwrite

Extract kexts from mkext

$ mkdir /tmp/Extensions
$ mkextunpack -d /tmp/Extensions Extensions.mkext

Copy kexts and remove unwanted kexts

$ cp -R nForceLan.kext /tmp/Extesions/
$ cp -R AppleNForceATA.kext /tmp/Extensions/
$ find /tmp/Extensions/ -name "*Intel*" -print0 | xargs -0 rm -R

Cache kext into mkext

$ sudo chown -R root:wheel /tmp/Extensions/
$ sudo chmod -R 755 /tmp/Extensions/
$ kextcache -a i386 -m /tmp/Extensions.mkext /tmp/Extensions

Copy Extenions.mkext to /System/Library on the ISO

$ cp /tmp/Extensions.mkext .

That’s it, now unmount the ISO and burn it to a DVD. Now we are ready to move on to the next step. I’ll be posting the details for actual installation Mac OS X 10.5.6 tomorrow.

/tmp/Extensions

In the mean time find out the specifications of your box. I’m using GIGABYTE GAPM61SME-S2 motherboard with AMD Athlon X2 CPU. If your specifications are just like mine go ahead and download all the files listed bellow, otherwise download 1-3 and then look for kexts for your motherboard.

System specification

• AMD Athlon X2 2800
• nVidia GeForce 6100/nForce 405 chipset
• 1 x 2 GB of DDR2 DIMM
• On board ethernet (nForce 10/1oo Mbit)
• Realtek ALC883 CODEC chip
• SATA HDD (nForce sata controller)
• USB Mouse
• USB Keyboard
• DVD Drive

Downloads

1. iPC OSx86 Leopard 10.5.6 Intel AMD SSE2 SSE3 DVD (Google and find out, you will have to download via Bit torrent)
2. Mac OS X 10.5.7 Update (http://keti.ws/95282)
3. Mac OS X 10.5.8 Combo Update (http://keti.ws/95283)
4. nForceLAN (http://keti.ws/94281)
5. AppleNForceATA (http://keti.ws/95281)

Steps

1. Patch the iPC DVD image (Otherwise the DVD will never boot)
2. Install Mac OS X 10.5.6
3. Remove all Intel kexts (Improves the boot time)
4. Install Mac OS X 10.5.7 update
5. Install Mac OS X 10.5.8 update

Await step 1, Patching the iPC DVD image tomorrow.

sub vcl_error {
set obj.http.Content-Type = "text/html; charset=utf-8";

if ( obj.status >= 500 && obj.status <= 505) {
C{
#include <stdio.h>
#include <string.h>

FILE * pFile;
char content [100];
char page [10240];
char fname [50];

page[0] = '\0';
sprintf(fname, "/var/www/errors/%d.html", VRT_r_obj_status(sp));

pFile = fopen(fname, "r");
while (fgets(content, 100, pFile)) {
strcat(page, content);
}
fclose(pFile);
VRT_synth_page(sp, 0, page, "<!-- XID: ", VRT_r_req_xid(sp), " -->", vrt_magic_string_end);
}C
} else {
synthetic {"
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<title>"} obj.status " " obj.response {"</title>
</head>
<body>
<h1>Error "} obj.status " " obj.response {"</h1>
<p>"} obj.response {"</p>
<h3>Guru Meditation:</h3>
<p>XID: "} req.xid {"</p>
<address>
<a href="http://www.varnish-cache.org/">Varnish</a>
</address>
</body>
</html>
"};
}

return (deliver);
}

Hope someone will find this useful as I had to put some effort to find out all the internal Varnish function names

If you hadn’t noticed my site was giving HTTP 500 errors last couple of days. The issue was found to be a segfault and it’s fixed now. That got me to come up with a set of funny and slick HTTP error pages. I only came up with HTTP 5xx error pages, I believe HTTP 4xx error pages should be specific to the site. You can download them here. If you want to take a peek, here is the list. HTTP 500, 501, 502, 503, 504, 505. Feel free to modify them and share what you come up with.

1. Clone the trunk

   git svn clone http://svn.wp-plugins.org/web-invoice/trunk/
   

2. Make your changes
3. Commit changes locally

   git commit -a
   

4. Pull new changes (e.g. new release). Git is very good at merging, you will not have conflicts unless you edit exact same lines in the local version. Still a manual merge shouldn’t be too complicated

   git svn rebase
   

In the example I have taken the svn trunk of Web Invoice WordPress plugin. Hope you find this information useful next time you hack a WordPress plugin.

If you have a Dialog Family package please go through your bills for February and March (April if you have already got it) 2009 and you will see the difference. Please post a comment if you are affected and even if you are not affected leave a comment then we might be able to find a pattern . It might not affect you if your primary connection makes more than Rs. 250 worth of local calls, not the case with me.

If you want to see my bills please leave a comment, it’s 8 pages, little too much to post in a blog.

I believe this is clearly deceiving the public. Shame on you Dialog GSM.

• Oracle has come to a definitive agreement to acquire Sun. See http://keti.ws/41284 . Wonder where MySQL will head #
• @hunch is impressive. Checkout http://www.hunch.com/ . But you will have to wait for an invitation. #
• Sign into my TwitterRemote on http://twittercounter.com/mohanjith so I know when you check my stats! #

As I promised, here is the post that will discuss in detail how I configured my cluster of 2 nodes to host my sites.

Setting up SSH tunnels

You have to setup a SSH tunnel between the nodes. In order to do that you need to allow restricted root logins into your nodes. Using your favourite text editor edit /etc/ssh/sshd_config and change the line PermitRootLogin to PermitRootLogin forced-commands-only.

Then generate SSH authentication keys for all your nodes and add the public keys to /root/.ssh/authorized_keys on other nodes. Keys can be generated by running ssh-keygen. By default your private key is stored in /root/.ssh/id_rsa and public key in /root/.ssh/id_rsa.pub. Your public key will look similar to bellow (Key shortened for brevity)

ssh-rsa AAAA...w== root@example.com

To enable tunnel only access via root you need to add tunnel="0",command="/sbin/ifdown tun0;/sbin/ifup tun0" before your public key in /root/.ssh/authorized_keys. Your /root/.ssh/authorized_keys will look something like bellow.

tunnel='0',command='/sbin/ifdown tun0;/sbin/ifup tun0' ssh-rsa AAAA...w== root@example.com

Now setup the actual tunnel. Add following lines to /etc/network/interfaces in the “server”

auto tun0
iface tun0 inet static
address 10.100.2.1
netmask 255.255.255.0
pointopoint 10.100.2.2

and the following in the “client”

auto tun0
iface tun0 inet static
pre-up ssh -S /var/run/ssh-myvpn-tunnel-control -M -f -w 0:0 example.com true
pre-up sleep 5
address 10.100.2.2
pointopoint 10.100.2.1
netmask 255.255.255.0
up route add -net 10.100.2.0 netmask 255.255.255.0 gw 10.100.2.0 tun0
post-down ssh -S /var/run/ssh-myvpn-tunnel-control -O exit example.com

Now you only have to restart networking to enable the tunnel. Now your nodes will be in their own VPN.

Setting up document root replication (rsync)

Share /var/www via rsync. You need to install rsync and add following to /etc/rsyncd.conf if they are not already there.

max connections = 2
log file = /var/log/rsync.log
timeout = 300

[www]
comment = DOC Root
path = /var/www
read only = yes
list = yes
uid = www-data
gid = www-data
auth users = replicator
secrets file = /etc/rsyncd.secrets

Add following cron jobs to www-data crontab (crontab -e)

1/10 *  *   *   *    test -r /tmp/rsync.docroot.lock || touch /tmp/rsync.docroot.lock && rsync -aP rsync://replicator@10.100.2.2/www/ /var/www/ --password-file=/etc/rsync.secrets  --contimeout=30  > /dev/null 2>1 && rm /tmp/rsync.docroot.lock

1/10 *  *   *   *    test -r /tmp/rsync.docroot.lock || touch /tmp/rsync.docroot.lock && rsync -aP rsync://replicator@10.100.2.1/www/ /var/www/ --password-file=/etc/rsync.secrets  --contimeout=30 > /dev/null 2>1 && rm /tmp/rsync.docroot.lock

Setting up session_mysql

Next let us setup session_mysql such that we can forget about replicating PHP session .

Install php5-dev and libmysql++-dev, download session_mysql and extract it, running following commands as root within the extracted location.

export PHP_PREFIX='/usr'
$PHP_PREFIX/bin/phpize
./configure --enable-session-mysql --with-php-config=$PHP_PREFIX/bin/php-config --with-mysql=$PHP_PREFIX
make
make install

Create the database to store the session data with the following SQL

create database phpsession;
grant all privileges on phpsession.* to phpsession identified by 'phpsession'; -- CHANGE DEFAULT PASSWORD
create table phpsession(
sess_key char(64) not null,
sess_mtime int(10) unsigned not null,
sess_host char(64) not null,
sess_val mediumblob not null,

index i_key(sess_key(6)),
index i_mtime(sess_mtime),
index i_host(sess_host)
);

Add the following to your php.ini (or /etc/php5/conf.d/session_mysql.ini)

session.save_handler = 'mysql'
session_mysql.db='host=localhost db=phpsession user=phpsession pass=phpsession'

Do not forget to change the default password. Restart Apache or Lighttpd (or any other web server you are using).

MySQL asynchronous two way replication

I’m sure some of you are asking why I went for asynchronous replication. Main reasons being flexibility and lack of nodes (My cluster is just 2 nodes).

Stop MySQL from listening only to local connections. Remember to review your user table (mysql.user) to make sure you don’t grant wild card access like 'user'@'%'. Comment out bind-address in/etc/mysql/my.cnf in all nodes. Then add following to node1

server-id               = 1
replicate-same-server-id = 0
auto-increment-increment = 2
auto-increment-offset   = 1
log_bin                 = /var/log/mysql/mysql-bin.log
expire_logs_days        = 10
max_binlog_size         = 100M

master-host = 10.100.2.2
master-user = slave_user_0
master-password = your$password
master-connect-retry = 60

and following to node2

server-id               = 2
replicate-same-server-id = 0
auto-increment-increment = 2
auto-increment-offset   = 2
log_bin                 = /var/log/mysql/mysql-bin.log
expire_logs_days        = 10
max_binlog_size         = 100M

master-host = 10.100.2.1
master-user = slave_user_1
master-password = your$password
master-connect-retry = 60

Now create the users only granting them with replication rights. Also make sure you specify the hostname or the IP to make sure someone is not offloading your data . Following SQL will create the users given in the example. You will have to run the command in both nodes as the data in either node is identical.

CREATE USER 'slave_user_1'@'10.100.2.1' IDENTIFIED BY 'your$password';

GRANT REPLICATION SLAVE ON * . * TO 'slave_user_1'@'10.100.2.1' IDENTIFIED BY 'your$password' WITH MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0 ;

CREATE USER 'slave_user_2'@'10.100.2.2' IDENTIFIED BY 'your$password';

GRANT REPLICATION SLAVE ON * . * TO 'slave_user_2'@'10.100.2.2' IDENTIFIED BY 'your$password' WITH MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0 ;

Now start MySQL and run following in mysql prompt on each of the nodes.

reset master;
stop slave;
start slave;

Finally

Now you have a cluster of 2 nodes where you can run your PHP site. Your databases are replicated, your user session data is replicated and your document root is replicated. Have fun, if you have issues please post it as a comment.

Until recently I used one Linode VPS for hosting all my sites. On 26th March, there was a DDoS attack on one of the Linode customers in the Fremont Datacenter (where my node was as well). This made my sites inaccessible for couple of hours. This got me thinking, what could be done to mitigate such downtime. Answer of course is having a load balanced and high availability cluster. However I couldn’t afford 2 dedicated servers to do this, but I of course can afford 2 Linodes . I’ll try to explain how I set up a load balanced, high availability and shared nothing cluster using Linodes (you can use any VPS or dedicated server). I used two Linode 540 s for the job.

All of my web sites are either using PHP, Python or Perl. All of them are using MySQL as the database. Problems I had to solve were;

1. replicate files across the nodes
2. replicate databases across the nodes
3. replicate session (PHP session variables) across the nodes

All the replication needs to be done securely, so I went for a SSH tunnel between the nodes of the cluster. Over which I’ll;

1. use rsync to replicate/synchronize the document root
2. use MySQL asynchronous replication (not a NDBCLUSTER) to synchronize data across the nodes
3. use session_mysql PECL extension to store PHP session in MySQL database transparent to all applications

Check back next week when I’ll post with configuration examples on how I configured my server. If you are in a hurry above pointers are good enough to get you started.

Now to get to the point, the e-mail templates are found in ‘Web Invoice’ -> ‘E-mail templates’.  There are three templates,

• Invoice e-mail – First e-mail your client receives about the invoice
• Reminder e-mail – E-mail sent when send reminder(s) is selected
• Receipt e-mail – Sent when the client makes a payment. You also need to set ‘Send Payment Confirmation’ to yes in Settings

All variables are of the format %variable_name. Bellow you will find the list of variables available in the current version.

• %call_sign – First name + Last name of the client
• %business_name – Business name as set in the ‘Settings’
• %recurring – Recurring or not
• %amount – Amount, with currency symbol and currency formatted
• %link – Link to the invoice
• %business_email – Business e-mail as set in the ‘Settings’
• %subject – Invoice subject
• %description – Invoice description

You can definitely use the default templates as a guideline for your templates. IMHO, default templaes are awesome

Don’t go away, there is more. You can write your own plugin to add more variables. e.g. you want to use web invoice along with a booking system. In your plugin add a filter for web_invoice_email_variables and add to the global array (variable) $web_invoices_email_variables.

I want to hear what you think about this feature or Web Invoice in general. Please post your ideas and comments in the Web Invoice community forum. Do not forget to subscribe to my RSS feed to get latest news about WordPress plugins and all things web