The basic problem is this: you have server “A” with a bunch of packages – let’s say PHP-related stuff – installed you need for you application. You need to get the same application working on server “B”, which is not an exact copy of server “A” and is missing some of the packages.

Mixing and matching RPMs by hand is a tedious and error-prone process. Here’s a basic, semi-automated process for getting through this task. Keep in mind that these commands need to be executed as root. Also, server “A” and server “B” need to be running the same (or very similar) Linux flavor and version.

On server “A” generate a list of installed packages – we use PHP* packages in this example – and save it to a file:

rpm -qa | grep ^php | sed 's/-[0-9]/@/g' | awk -F'@' '{print $1}' | sort -u > /tmp/rpm_list.txt

The result will look something like this:

php
php-cli
php-common
php-gd
php-ldap
php-mbstring
php-mcrypt
phpmyadmin
php-mysql
php-pdo
php-pear
php-pear-Auth-SASL
php-pear-Net-SMTP
php-pear-Net-Socket
php-snmp
php-xml

Now copy this file to server “B” and try to install every package in the list (in this example we use CentOS and yum):

for i in `cat /tmp/list` ; do yum -y install $i ; done

This will install whatever is not already installed and available from the repositories. It is important to make sure server “B” has the same or equivalent repositories as server “B”. Also, make sure you have plenty of disk space available.

If you have passwordless SSH from server “A” to server “B” and passwordless “sudo su – root”, you can do the whole thing in one line:

rpm -qa | grep ^php | sed 's/-[0-9]/@/g' | awk -F'@' '{print $1}' | sort -u > /tmp/list ; scp -p /tmp/list server_b:/tmp/list ; ssh -qt server_b 'cat /tmp/list | while read i ; do sudo su - root -c "yum -y install $i" ; done'