Linux Cloud Technologies 2013

  Build the cloud on Linux!  This year looks very promising for Linux when it comes to building your private cloud using open source technologies.  Finally, Linux-based software and application

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Linux Cloud Technologies 2013

Join CentOS 6 to Active Directory Domain

by on October 1, 2013 at 4:03 pm

Joining CentOS 6 or Red Hat Enterprise Linux 6 to an Active Directory Domain is relatively simple.  While Active Directory is proprietary software developed by Microsoft, it’s fairly ubiquitous in medium and large environments, thus integrating Linux and Windows services is very common in this day and age.  DNS has to be working properly.  You should be able to resolve mydomain.com using DNS.

First, we need to install winbind.  This is the Samba service that integrates users, passwords, and other important functions with Active Directory.

yum install samba-winbind

That command should install any and all dependencies necessary.  Another step is to install software necessary for initializing Kerberos tickets.  While not strictly necessary to join the Domain initially (I believe), it makes troubleshooting a little easier.

yum install krb5-workstation

After those two packages are installed, you can run authconfig-tui to automatically setup pam and other important config files.  See the screen shots below for example settings.


The above selections are appropriate.  Use fingerprint reader is not needed unless your workstation has a fingerprint reader.


This stage is very important.  Security model should be set to ADS.  Domain should be the name of the domain without the top level domain.  If your domain looks like my.domain.com, then you should put “MY” in this field.  Domain controllers are the FQDN for each domain controller you wish your system to use.  Unlike Windows, these are not automatically discovered by CentOS or RHEL 6.  Separate each domain controller by a space.  ADS REALM should be the full name of your Domain in ALL CAPS.  Template shell can be whichever you choose.  If you want to enable domain users the ability to log in by default, select one of the shells.  If you want to disable ssh/local login by default, select /sbin/nologin.

Next, select Join Domain and enter your Domain Admin username and password in the boxes provided.  You should enter just the username, do not enter any domain information here.

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How to RDP from CentOS 6 using Network Level Auth

by on October 1, 2013 at 3:22 pm

Connecting from CentOS 6 to Windows Server 2008 R2 used to be impossible if you had Network Level Authentication required on your Windows Servers. However, the latest version of rdesktop (1.8 as of this writing) finally integrates NLA. Unfortunately, if you’re using CentOS 6 or Red Hat Enterprise Linux 6, the newest version is not currently available from the EPEL or base repos.   In this article I’m going to show you how to build and install the software so it works correctly.


in CentOS, How-To, Red Hat

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Install OpenStack Grizzly on Fedora 19 with Quantum Networking

by on August 14, 2013 at 7:35 pm

I recently registered for an watched a Red Hat online seminar, Taste of Training for the upcoming Red Hat Open Stack course.  Up until very recently, Red Hat OpenStack was only a technology preview, but now Red Hat is offering full support for OpenStack as part of it’s Red Hat Cloud Infrastructure product suite.

If you’re already familiar with OpenStack and/or Fedora, you can refer to this ’3 step’ guide from Red Hat:  http://openstack.redhat.com/Quickstart  Since you’re using Fedora 19, you’re not likely going to actually be able to complete the install in 3 steps as the guide suggests.  I have found there are numerous steps that must/should be modified for a smooth installation, and I have compiled those steps here for my readers.

What I’m going to outline here are some of the necessary tips and methods I gleaned from hours of frustration.  I also hope to include pretty screen shots for your convenience :).

I also intend to use Quantum networking, and (coming soon) GlusterFS as cinder storage.


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Connect to SQL Server with Python

by on July 5, 2013 at 2:23 pm

Recently I was tasked to rewrite some Perl cgi scripts.  My time is valuable to me, so I rewrote them in Python!  One of the functions of the cgi scripts was to connect to a Microsoft SQL Server 2008 r2 instance.  A quick glance at the perl scripts showed me we were using ODBC to connect to SQL Server.  After a few hours of reading online, I settled upon what I believe is the best method, using pyodbc.

pyodbc is an open source library for python, available at https://code.google.com/p/pyodbc/  Installation is pretty straight forward, but I will outline the steps here and help you connect to SQL Server as well.


in How-To, Red Hat

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Centos 6 Apache Kerberos AD SSO

by on May 21, 2013 at 7:22 pm

I recently setup a RHEL / Centos 6 Apache websever at work that integrates with Active Directory (AD) and Kerberos for a single sign on (SSO) web resource.  This took me a lot more time than I thought it would, but that’s because the tutorials I was reading were either wrong, or didn’t apply to my situation.  I am outlining the steps I took below to help others who may wish to have a similar setup.


in CentOS, How-To, Red Hat

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Install vSphere CLI in CentOS 6

by on May 7, 2013 at 4:04 pm

I recently installed VMware’s vSphere CLI 5.1 tools on a CentOS 6 x86_64 VM.  Despite the rather reassuring documentation released by VMware, installing these tools was no simple task.  I will outline the steps that I took for a successful installation of the vSphere CLI software, as some of it is not very obvious, especially for beginners.


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RHCSA Study Guide RHEL 6

by on February 9, 2013 at 9:29 pm

If you are considering obtaining a certification in Linux to advance your career, a great certificate to hold is the Red Hat Certified System Administrator (RHCSA).  Red Hat is the premier enterprise Linux distribution, used in countless production environments worldwide.  Red Hat certifications require a candidate to sit for a practical exam; there are no multiple choice questions, you must actually configure a live system.

Please excuse the formatting of this post.  I am working to clean it up.
Throughout the web, you can find a collection of study guides for the RHCSA.  I have created my own, which is a collection of my own notes and the notes of others.  I highly recommend using the following book:
RHCSA/RHCE Red Hat Linux Certification Study Guide (Exams EX200 & EX300), 6th Edition (Certification Press)

Current exam objectives can be found here:  http://www.redhat.com/training/courses/ex200/examobjective

SELinux user guide:  http://docs.fedoraproject.org/en-US/Fedora/13/html/SELinux_FAQ/index.html#id3028666


in Distros, Red Hat

Fedora 18 Review

by on February 7, 2013 at 6:37 pm

Fedora FreedomFedora 18 was released in the middle of last month without too much fanfare.  I suspect this is likely because the beta was extremely buggy; many people had trouble installing Fedora 18 Beta using the new Anaconda installer interface, and I myself even filed a bug report for GRUB2 not loading after installation (which is still outstanding).

Why should you be interested in Fedora 18?  Well, aside from the fact that it’s already a very popular desktop distro, according to this article from ServerWatch.com, Fedora 17 and Fedora 18 will debut some of the features slated for release in RHEL 7, which is due out within the next year or so.



Configuring CentOS 6 Web Server

by on May 9, 2012 at 7:07 pm

Centos 6 in 3DIn this article, I’m going to be outlining the steps to install and configure a complete web server on a base install of CentOS 6.  (Which should be compatible with Scientific Linux 6 as well as Red Hat Enterprise Linux 6)

I personally don’t prefer to install package groups relating to “LAMP” or similar during initial installation because I’m simply too lazy to review each and every package that is included in those groups, and what the dependencies are. By installing the required packages using yum, this allows you to install just the software you’re looking for, without worrying about dependencies. This software stack is time tested; we’ll install on CentOS’s latest release, and test a few popular applications while we’re at it!

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