Problem loading/starting a KVM virtual machine on a CentOS 6.5 host that has SELINUX disabled

If you have recently built a KVM host for all your virtual machines and left SELINUX enabled, then all will be well, but what happens when you turn that setting off. Well you will end up with VM's that won't load with the error message

error: Failed to start domain Ubuntu1404
error: unsupported configuration: Unable to find security driver for label selinux

It is easy to fix , use the following command and just remove the seclabel section on the virtual machine domain XML - virsh edit Ubuntu1404

# virsh edit Ubuntu1404
...
  <;seclabel type='dynamic' model='selinux' relabel='yes'>;
    <label>system_u:system_r:svirt_t:s0:c95,c664</label>
    <imagelabel>system_u:object_r:svirt_image_t:s0:c95,c664</imagelabel>
  </seclabel>  

Once you have done that, the domains will load as normal.

Make sure if you have backup's of the domain XML, they are also changed, as I have found that they will over write the domain if your not careful

Check in /etc/libvirt/qemu to make sure the changes have happen, and the XML has been updated.

Fixing a problem with VMware vcloud when putting a Virtual Machine back into the cloud Catalog

If you use vcloud, then I'm sure you have pushed fully patched and configured virtual machines back into the catalog as gold masters many times. If you have customised scripts, then you may or may not have come across this problem.

However yesterday, I came across a problem where the custom script settings within vcloud version 5.5 were not working, and the init scripts were not be run when you created a new vapp. This is a setting that tells the VM, if they have been run or not

It turns out the code for pushing VM's back into the catalog was not resetting the static file needed, to tell the init scripts to run correctly. If you look in .customisation in roots home directory, you can see the file it is looking for.

So , the work around - after much digging around in the code to find the file that VMware tools were looking for - is as follows

On a Linux system just type the following.

touch /.guest-customisation-post-reboot-pending

Once this file is in place, shutdown your VM, copy it back to the catalog, and all will be fine on the next start - it will run your desired init scripts as you wanted in the first place ;-)

Hope this saves you some time.

Using a Jumpbox virtual machine as a mobile aide memoir

If like me you have trouble keeping track of all the technical information that comes across your desk on a weekly basis, then I might just have the answer for you.

I have started to use a virtual moinmoin wiki image from Jumpbox, the virtual machine supplier, which just happens to be free, to record all the detailed technical things I need to remember.

The beauty of this solution, is that as long as I have a Xen virtual server around, I can run up this virtual machine where ever I want and have full access to all my information. It also works with VMware, so you could just as easily use VMware server or player, in my case all this would all be done using Linux as the host.

The thing I like most about it is that it can remain accessible, long after all of the underlying technology has been replaced. You can also backup the data you have put in the wiki with ease, and that can be restored to another virtual machine running on a different form of virtualization, neat huh. Another nice feature of this is that it would be trivial to put this into the cloud for global access or even team sharing, it just gets better ;-). However, not all companies allow unfettered access to the cloud, so it's always a good idea to have access to both.

If you are prepared to pay Jumpbox a few pounds a year, which I would recommend, you can do exactly the same with Mediawiki, which offers more facilities.

Getting a Jumpbox VM to work with Redhat EL 5 64 bit

If you use virtualization a lot , then I'm sure you will have come across a great company that offers a whole range of pre-built open source virtual images. That company is Jumpbox. I have used several of their images with great success, and the time to deploy is extremely quick, especially with VMware ESX or VMware server.

On this occasion though I wanted to get a moinmoin wiki going on a 64bit Redhat Xen server, and the default install script supplied with the images is for 32bit systems. It fails, telling you it can't find qemu, which is true as it won't given the default script. Also note that you must have hardware virtualization switched on in the BIOS to get these images to work on 32 or 64 bit systems.

You have to make a minor change to one part of the config file, JumpBox.xen , simply because this is where RH put the 64bit version of qemu.

Here is the section that needs changing.

devfiles = [
'/usr/lib/xen/bin/qemu-dm',
'/usr/lib/xen-ioemu-3.0/bin/qemu-dm'
]

I changed the line '/usr/lib/xen/bin/qemu-dm' to '/usr/lib64/xen/bin/qemu-dm'

You then use the start script "xm create -c JumpBox.xen", and the virtual machine is then visible in the virtual manager on the host server.