Enabling mod_rewrite in Apache 2.2

By default CentOS or RHEL flavours of Linux has Apache 2.2 installed. It often becomes a requirement to enable mod_rewrite on these servers. Techs who have been working with cPanel and server with control panels often finds it difficult to troubleshoot issues with a bare server. There are a few things to check or commands to execute in such case where mod_rewrite is shown enabled in the httpd.conf, but not working.

[root@cave html]# httpd -V
Server version: Apache/2.2.3

[root@cave html]# httpd -M
Loaded Modules:
core_module (static)
mpm_prefork_module (static)
http_module (static)
so_module (static)
auth_basic_module (shared)
auth_digest_module (shared)
….
…….
….
rewrite_module (shared)
proxy_module (shared)
proxy_balancer_module (shared)
proxy_ftp_module (shared)
proxy_http_module (shared)
proxy_connect_module (shared)

[root@cave html]# a2enmod rewrite

a2enmod is only to be used if the rewrite_module is not enabled in httpd.conf

Check for the “AllowOverride” settings. It should be set to “All“. By default it will be “None”

Things should work fine after this. Also I found a small good script to check at this URL to see whether mod_rewrite is enabled or not http://www.webune.com/forums/how-to-test-check-if-mod-rewrite-is-enabled-t40.html

Good Luck guys!

Magento Suhosin Values

Sometimes Magento admins face the issue of some values missing from the frontend even though the configuration would have shown to be saved from Backend. This could be due the limit in the number of values set by suhosin.

The common override for this issue is to have the following values set in .htaccess

php_value suhosin.mail.protect 0
php_value suhosin.memory_limit 128M
php_value suhosin.post.max_vars 5000
php_value suhosin.post.max_value_length 500000
php_value suhosin.request.max_vars 5000
php_value suhosin.request.max_value_length 500000
php_flag suhosin.session.cryptua off

For php.ini use the variables without php_value or php_flag

gpg: no writable public keyring found: eof

gpg –gen-key was the command issued and after a few entropy delay [+++++++++++++++++++++++++++.+++++....+++++++++++++++++++++++++........................+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.]

the command failed to return

gpg: no writable public keyring found: eof
Key generation failed: eof

Solution would be to execute rm -rf ~/.gnugpg as there were a few files in the server which was root owned.

If you face any error like “GPGME: Bad passphrase”, but you were never asked for a passphrase, probability that issue is with the memory. Just increase the memory limit and you should be fine. In ubuntu, it will be at /etc/security/limits.conf

Recompile PHP for Litespeed webserver

LSAPI is LiteSpeed’s open-source API between external applications and LiteSpeed Web Server. This how-to is for compiling and installing PHP + LSAPI on Linux, OS X, FreeBSD, Solaris, and so on.  LiteSpeed  comes with PHP 4.4.x compiled with LSAPI. To change the LightSpeed php to the latest stable one, we need to recompile the php with the LSAPI for LiteSpeed.

I  am trying to provide some info for doing this task.

Instructions:

a)  Download the required php  from php.net

wget  http://in2.php.net/get/php-5.2.11.tar.bz2/from/this/mirror

tar -xzvf  php-5.2.11.tar.bz2

cd php-5.2.11/sapi

b) Download and  the  latest LSAPI for PHP from http://www.litespeedtech.com/ into the “sapi” folder of php source:

wget http://www.litespeedtech.com/packages/lsapi/php-litespeed-4.10.tgz

tar  -xvf php-litespeed-4.10.tgz

c) Change directory to root PHP source directory and run commands:

cd ..

touch ac*

./buldconf –force

d) Configure/Compiling

If you have an  apache compilation already , remove the part   option “–with-apxs” and use    ” –with-litespeed”  . Also  you may need to change the “prefix” option too . So a basic  configure command would be like  this

./configure  ‘–prefix=/lsphp5′ ‘–with-litespeed’ ‘with-mysql’

make

make install

Note: You must compile PCRE support inorder for the default auto-index php script to work correctly

Post Install Configurations

1. Replace the existing lsphp binary with the new one.

Change the directory to the current installation of “lsws” ( it varies on different machines)

cd  /usr/local/lsws/fcgi-bin

mv lsphp lsphp.old

cp /php-5.2.11/sapi/litespeed/php lsphp-5.2.11

ln -sf lsphp5 lsphp-5.2.11

Check Installation

/usr/local/lsws/fcgi-bin/lsphp5 -v

It should return something like:

PHP 5.2.11 (litespeed) (built: Sep26 2008 14:09:09)
Copyright (c) 1997-2004 The PHP Group
Zend Engine v2.2.0, Copyright (c) 1998-2008 Zend Technologies

Notice litespeed in parenthesis. This means that the PHP binary has litespeed (LSAPI) support builtin.

2. php.ini

The php.ini file will be located at /usr/local/lsws/php/php.ini

If we want to use the old PHP.ini just copy it here.

# cd /usr/local/lsws/php
# mv php.ini php.ini.old
# cp /usr/local/ZEND/etc/php.ini .

3. Restart Litespeed Webserver

Finally restart LSWS and use our new PHP binary.

/usr/local/lsws/bin/lswsctrl restart 

How to recompile Kernel?

Kernel Recompilation

Compiling custom kernel has its own advantages and disadvantages.  It helps to optimize the kernel to your environment (hardware and usage patterns).  I shall try to guide you through Kernel recompilation process.

Step 1:

Download the kernel source

cd /usr/local/src

wget  http://www.kernel.org/pub/linux/kernel/v2.6/linux-x.y.z.tar.bz2

Note: Replace x.y.z with actual version number.

Step 2:

Extract the  source file

tar -xjvf linux-x.y.z.tar.bz2

Step 3:

Patching the Kernel

If you are requested to apply any patches , follow these steps

a) Move the downloaded kernel patch to the /usr/local/src directory.

b)  Extract the patch file

c)  Patch the kernel  source using the extracted  patch file

cd /usr/local/src/linux-x.y.z

patch -p1 < patchfile-2.2.x

Now the  Kernel Source is patched against known  vulnerabilities.

Step 4:

Configuration

If you are trying to upgrade the Kernel of already running server , it is always better use the existing configuration. To do this follow these steps

#uname -a
Linux  Server1  2.6.18-164.el5 #1 SMP Thu Sep 3 03:28:30 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux

# cd /boot

There you can see different configuration files as given below

#ls

config-2.6.18-128.el5    initrd-2.6.18-128.el5.img  message
config-2.6.18-164.el5     initrd-2.6.18-164.el5.img  quota.user*

identify the configuration file corresponding to the version of OS installed , In our case it is config-2.6.18-164.el5 . We are  copying this file to the downloaded kernel source  to use it during configuration.

#cp -p config-2.6.18-164.el5 /usr/local/src/linux-x.y.z/.config

# make clean

# make mrproper

# make menuconfig

You have to select different options as per your need.   If you  intended to use the existing configuration ,specify the path to the file  ( .config in this case) by selecting the option

“Load an Alternative configuration file”

Step 5: Compilation

Compile the Kernel using the following commands

Compile to create a compressed kernel image

# make

Compile kernel modules:

# make modules

Install kernel modules

# make modules_install

Step 6: Install Kernel

If the above steps completed without any errors , now its the time to Install the new Kernel

# make install

It will install three files into /boot directory as well as modification to your kernel grub configuration file:

System.map-x.y.z

config-x.y.z

vmlinuz-x.y.z

Step 7:  Create the Initrd image

Type the following command :

# cd /boot

# mkinitrd -o initrd.img-x.y.x  x.y.z

initrd images contains device driver which needed to load rest of the operating system later on. Not all computer requires it, but it is  better  to create one

Step 8: Boot Loader Modification

Mofdify the boot loader to boot the new OS as default . Check the documentaions corresponding to your boot loader

Step 9: The last step

execute the following command

#reboot

Wait a few minutes and once it is up , you can see that the new Kernel is loaded