So I'm working on regisgtering 100+ RHEL systems to a new RHN Satellite server. The following command line for loop magic mad this a snap, thought it was worth publishing.
"The Cloud" or "Cloud Computing" are some of the latest buzz words in the industry. The definition of either of these terms is... well.. cloudy. The basic idea is that your applications are virtualized across a global network of hypervisors. Not too dis-similar from the VM Clusters run at the institution that I work at, just on a much larger scale.
I run a Xen vm system which in turn hosts all of my linux servers. Recently, I had reason to mount the disk image from one of the vm's on the xen host.
I've found little documentation on this, so I thought i'd post what I ended up doing.
First, make sure the vm is down. Then you can mount it's disk image.
I used kpartx to mount the image as a loop.
We've started to look into memory ballooning on RHEL and KVM. I thought I'd document some of my findings here.
The concept is simple. You have your RHEL host, running KVM, that host runs a number of virtual machine guests. The guests can be anything that runs on the chip archetecture that you're emulating. In my case, x86_64 and i386. We run some Windows guests, and mostly RHEL. In my testing, i'm using a RHEL guest. I'll test this on Windows at some point, and see what happens.
I run a number of VM's under KVM. Windows VM's, RedHat VM's, SLES and Ubuntu VM's. Recently, we attempted to provision a VM using LANDesk. We ran into an issue where KVM was not assigning a BIOS serial number. LANDesk uses the BIOS serial number to identify the client to the LANDesk server.
Please bear with me. After a SECOND almost successful attempt at compromising my server using flaws in Serendipity, I've decided to move to Drupal.
You'll find the old blog entries here, but not much else. I'll get more moved over as I can.
I found myself at work the other day, without my keys. Luckily our offices share the same key, so a co-worker was able to get me into my office. Not so my desk though. I don't keep anything terribly sensitive in my desk, because i've always felt the lock was a tad on the cheap side. Though i've attempted to pick it in the past with no success.
Today i really wanted to get at a sheet that I had in my desk drawer. So i thought I'd give it another shot. I'm no locksmith. Nor am I a pro at picking locks, but I've had luck in the past with this paper clip that i keep in my wallet, and a small pocket knife that i have in my pocket all the time. I take the screwdriver/file on the knife, and use it to put pressure on the tumbler, and then rake the pins in the lock, to try to get the tumbler to turn. This has worked on low grade locks in the past. I used to use this method to unlock the hdd write locks in college so i could install Netscape on the IE only computers in class. Today I set about picking the lock using my old method, and discovered a new method... I've seen locksmiths re-key locks in the past. They used a specialized tool, and just pulled the whole tumbler out, and replaced it with another one keyed differently but i never really knew how they got the old tumbler out. Well, today I found out. I, quite accidentally i might add, pulled out the entire tumbler in my desk lock using my paper clip. After I'd done this, i was determined to figure out HOW i did it. A spare key for my desk, which was IN the locked desk drawer, helped me shed light on this. It also gave me a very good look at how locks work in general. I'd already had a basic knowledge, but this allowed me to solidify it. Basically, there are 6 pins. Well when you put your key in, it contacts 5 of these, and moves them into just the right position that the tumbler is allowed to spin. The tumbler is then attached to some other mechanism which actually unlocks the drawers. The 6th pin, is there solely to hold the tumbler in! I was able to hit the 6th pin, and unlock the tumbler. At that point, the whole tumbler came out in my hand regardless of the presence, or lack thereof, of the key. I was then able to use my pocket knife to turn the mechanism which unlocked the drawers.
A friend called me MacGuyver for figuring this out, which prompted an earlier blog post. It does sound rather funny when you think about it, i defeated the "Security" on my desk with a straightened paper clip... Needless to say, I have even less faith in this desk lock now, and i'll be even less likely to put anything of value in it.
"Here we are again, on this rust-bucket of a boat." thought James, as he looked around at the poorly supplied vessel he found himself on. Hardly any ammunition, a single torpedo, practically defenceless. "It's a good thing I've got Wren to look out for me...". James, and two other mercenaries were contracted by a ships captain that they've worked with in the past, to investigate a distress call that was received from one of the oil rigs still in operation off of the gulf coast. They were en-route.
Over the past 20 year or so of my life, I've been tinkering with these things called computers. I started out when i was young, in my parent's attic, on my Dad's Atari computer. He had a simple system, one 5.25" floppy drive, and a hand full of software for it. He used it for word processing, and a hand full of games. I can vaguely remember the first time we sat down, and he showed me how to load up a game off of one of these floppies. The procedure involved in turning the thing on, and when the disk had to be put in, when to push the power button all of that.