Reverse engineering the “AADLoginForLinux” in order to tweak proactive user configuration

Introduction

Last summer I posted about taking a look under the hood of the Azure Active Directory integration for a Linux Virtual Machine. For today, let’s take it a bit further… What if we would want to pre-provision a set of UIDs (User IDs) & GIDs (Group IDs) on a range of virtual machines for cross machine consistency. Let’s say, we would want to make use of an NFS drive and use the same UID/GID across all those boxes. Can we do that with the AAD extension? If so, how can we do it? Let’s hope we can… Otherwise it’ll become a rather short blog post.

 

Disclaimer

This post is based upon my personal experience reverse engineering how this extension works. This is by no means a support statement. If you’re a technical nut (like myself) and want to know how you can tweak this at your own doing… Then this post is for you. 😉

Taking a look under the hood of the Linux VM Authentication

Introduction

Today we’ll do a deep-dive into how you can log into an Azure Linux VM with Azure Active Directory (AAD). In essence, we’ll go through the following documentation flow, and then take a look how that looks under the hood.

 

Part one : “Creation”

The part on creating & integrating the VM is VERY straightforward…

• Create a resource group
  
• Create a Linux virtual machine
  
• Add the “Azure AD login VM”-extension
  

And that’s it! Really, that’s it…

Azure File Share : Issue mounting outside of the Azure region from Ubuntu Linux

Today I was setting up a deployment with two hosts ;

• One in West Europe (“WE”)
• One in North Europe (“NE”)

The objective was to have a shared mountpoint between both. So I created a storage account in the region West Europe. In this storage account I created a file share, and mounted it on to the VM located in WE. Though when using the exact same config in NE, I got the following error message ;

mount error(13): Permission denied
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)

Getting VIM to acknowledge your Drupal files

Are you a die-hard vi(m) user like me and wanted to have the php color coding for all your drupal files?

It’s quite simple actually. Add the following lines to your ~/.vimrc file (create it if it doesn’t exist):

au BufReadPost *.module,*.install,*.theme set syntax=php

OpenSource Storage Management

I came across OpenFiler a while ago and was intriged by it. Now I’ve taken the liberty to testing it in my lab, and I must say that I’m impressed by the features. It’s something every sysadmin should check out to see if it isn’t a viable solution for their overpriced storage solution… 😉

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Openfiler is a powerful, intuitive browser-based network storage software distribution. Openfiler delivers file-based Network Attached Storage and block-based Storage Area Networking in a single framework. Its uses the rPath Linux metadistribution and is distributed as a stand-alone Linux distribution. The entire software stack interfaces with third-party software that is all open source.

File-based networking protocols supported by Openfiler include: NFS, SMB/CIFS, HTTP/WebDAV and FTP. Network directories supported by Openfiler include NIS, LDAP (with support for SMB/CIFS encrypted passwords), Active Directory (in native and mixed modes) and Hesiod. Authentication protocols include Kerberos 5.

Openfiler includes support for volume-based partitioning, iSCSI (target and initiator), scheduled snapshots, resource quota, and a single unified interface for share management which makes allocating shares for various network file-system protocols a breeze.

Find out who is monopolizing or eating the CPUs

When you need to determine which process is monopolizing or eating the CPUs. Following command will displays the top 10 CPU users on the Linux system.

ps -eo pcpu,pid,user,args | sort -k 1 -r | head -10

or

ps -eo pcpu,pid,user,args | sort -r -k1 | less

Output
%CPU PID USER COMMAND
96 2148 vivek /usr/lib/vmware/bin/vmware-vmx -C /var/lib/vmware/Virtual Machines/Ubuntu 64-bit/Ubuntu 64-bit.vmx -@ ""
0.7 3358 mysql /usr/libexec/mysqld --defaults-file=/etc/my.cnf --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-locking --socket=/var/lib/mysql/mysql.sock
0.4 29129 lighttpd /usr/bin/php
0.4 29128 lighttpd /usr/bin/php
0.4 29127 lighttpd /usr/bin/php
0.4 29126 lighttpd /usr/bin/php
0.2 2177 vivek [vmware-rtc]
0.0 9 root [kacpid]
0.0 8 root [khelper]

If you’re interested in more information on Linux CPU utilization then check out the related article on nixCraft here.

Yet another windows versus linux slideshow?

The next slideset aligns with my vision about “Linux versus Windows”. But it’s presented a bit nicer than the simple bullet points I used a whlie back. 😉

http://static.slideshare.net/swf/ssplayer2.swf?doc=submission-1217274166156869-8&stripped_title=linux-is-a-windowskiller-myth-or-reality

Which is the greenest; disks or flash?

In his latest blog post, Anything But a Flash in the Pan, Jonathan Schwartz. touches a good point… We have RAM memory for “on the fly” memory and hard drivers to have persistent storage. Yet flash memory could (let me stand corrected; WILL) be used as a middle way option. Put apart the commercial notes (links towards Sun & ZFS), and you’ll probably find it an interesting read like me.

There are only two kinds of storage devices – those that have failed, and those that are about to fail. That’s the view most data centers have about the traditionally mechanical devices pejoratively referred to as “spinning rust.” All disk drives fail, cheap drives fail faster.

DevWork’s Ten Essential Linux Tricks

Learn these 10 tricks and you’ll be the most powerful Linux® systems administrator in the universe…well, maybe not the universe, but you will need these tips to play in the big leagues. Learn about SSH tunnels, VNC, password recovery, console spying, and more. Examples accompany each trick, so you can duplicate them on your own systems.

Lazy Linux: 10 essential tricks for admins

How to be a more productive Linux systems administrator

• Trick 1: Unmounting the unresponsive DVD drive
• Trick 2: Getting your screen back when it’s hosed
• Trick 3: Collaboration with screen
• Trick 4: Getting back the root password
• Trick 5: SSH back door
• Trick 6: Remote VNC session through an SSH tunnel
• Trick 7: Checking your bandwidth
• Trick 8: Command-line scripting and utilities
• Trick 9: Spying on the console
• Trick 10: Random system information collection

Seamless Linux applications on Windows

Seamless Options
One of the all-time-favorite articles here is “Running your dual boot windows inside Vmware Server within Ubuntu“. Yet some might like it the other way around, and a bit more seamless? Two handy options here are “VirtualBox” & “Ulteo Virtual Desktop“.

Virtualbox
You can put Virtualbox in the same range as Vmware. They provide a performant virtualization platform. Yet one of their core features (which I still miss in Vmware, apart from Fusion) is the “seamless” mode. It means your guest OS can appear on your desktop without having to be inside a window. You can run application (say notepad) and it will appear as a single window on your desktop.
More info?

Ulteo
With Ulteo Virtual Desktop, you just have to run the application you need to use from the Ulteo panel and its window will show up like any other Windows application. Ulteo steps in to avoid the point where you need to maintain your virtualization platform (as with the seamless solution of Virtualbox). See it as an application that will (install and) maintain the seamless solutions for you. Check out their website (and the /. comments).