Archive for December, 2012

Setting up “cloud services” at home sounds easy but proves to be hard

Sunday, December 9th, 2012

I have been using virtualisation at home for some time, since the days of vmware-server on Linux. It works well and if you have a sufficiently powerful box is a great way to experiment without destroying your own server or installing software which a few hours later you may want to remove again.

I also recently bought a Mac mini 2011, which I put in 16 GB of RAM and was hoping to set it up as a host to contain various virtual machines.  This was going to run Linux. I wanted to run the host as light as possible and do the real tasks inside my virtual machines.  I also wanted to use this server to migrate from an older PC I use for my day to day services (web, dns, email, ftp services etc).

Getting Linux installed on the Mac was a bit trickier than expected. I have been using RedHat since version 3.0.3 so prefer that to Debian or Ubuntu, if only because it is an environment that I am more familiar with. I tried in vain to get CentOS 6 to install on the Mac but it seems the required EFI boot loader does not work. Others have had problems too I think. Less surprising is that Ubuntu installed first time (credit to them for getting it to work on more exotic hardware), and when I tried Fedora 17 I saw that also worked, so that is what I am using. I would still prefer to switch to CentOS as it stays stable for longer, and playing the upgrade game with Fedora gets to be a pain.  Maybe some time soon…

There is a lot of noise around now about cloud computing and I had wanted to use something a bit more sophisticated than virt-manager on my PC.  This requires you to organise the exact setup of the boxes, network, disk images and other cloud platforms seem to make this management easier for you.

oVirt seemed promising and there is even a Fedora 17 repo and it is supposed to work out of the box according to various blogs and articles, but I had trouble getting it all up and running. If you run it on a single host it does require a lot of packages and software to be installed.  So after various attempts I gave up.

OpenStack is also pretty hot and has quite good documentation, though it seems complex perhaps because of the scale that it runs on in some deployments.  Again I read the manuals and documentation and had trouble getting the whole environment to work.  The configuration is quite complex, and it seems easy to make a mistake. If you do that then figuring out what is broken or why is pretty hard. Again this is a shame especially as this seems to be perhaps the most sophisticated of the 3 cloud environments I tried.

Family circumstances mean I have a lot less time than I would like to investigate but I did do quite a bit of homework before starting so this has been quite frustrating.

I then tried OpenNebula, version 3.8.1.  It seems that the software is still evolving quite quickly so has evolved quite a lot over time.  It also seems that this is the smallest package: the tar ball is tiny and at least on Fedora 17 it did not take me long to get the software installed (including sunstone-server).  I see this is tagged to be included in Fedora 17 but could not find actual packages to install.

There are quite a few howtos and tutorials but for OpenNebula, but some of these are for older versions, and if you follow them thing will not work as expected. (Differences in the templating options etc.) This is confusing for a new user.

I use Fedora 17 but do not see packages for OpenNebula. Working packages for Fedora, CentOS, Ubuntu etc would be most welcome as this would probably ensure that the different components were configured correctly with the OS components like virt-manager etc.

Most of the OpenNebula daemons have start and stop commands but no status command.  This would at least allow you check that the configuration was correct and the daemons correctly started, especially when doing manual installs.

I would like to see some sort of “check installation” command to allow for a more complete set of checks to be done to see if the installation is correct and complete, for each of the different components that makes up or is needed by OpenNebula.  In many places the documentation says “Assuming you have a correct kvm setup …”, “Assuming you have a correct isci setup …”, etc, yet provides no way for you to check if the setup of these base components actually works as required by OpenNebula.  Whether that documentation is included in the documentation or on a wiki somewhere “How to setup kvm on Fedora X for OpenNebula….” I do not really mind but I have had problems with PolicyKit not allowing oneadmin access to the virtual machine, with the virtual machines not seeing their disks (I think due to user/group permissions, as on Fedora 17 kvm seems to assign file ownership as qemu:qemu.), with the VNC connections in Sunstone not working, and I am pretty sure that most of these issues are “trivial” to fix if you have done this before and understand what OpenNebula expects and what the host operating system is doing “incorrectly”.

For initial testing including various standard template files which would useful, if only to allow helping to confirm simple things like:

    • booting from a cd image works
    • booting from a minimal hard disk works
    • booting from a hard disk with networking work (perhaps bridging or NATing out from the host’s network)
    • how to do a boot from a cdimage which will allow someone to install a new image on to a hard disk. This is a very typical usage pattern, and the exact Operating System or Linux distribution / version may vary.

I was confused by the network documentation and exactly how that relates to the underlying host’s network configuration.   This does not seem to be well documented but “assumed”.

To summerise these technologies are here and being used quite widely, but I would guess in larger environments where the people using them have time to investigate and set things up properly. I was hoping that to set these up at home would not be that hard, but have found it much harder than I had anticipated to do this just reading the documentation and trying on my own.  I think that all these platforms would be used more widely if they were more plug and play, that is they worked out of the box on most of the popular Linux distributions.

Having said that things have obviously progressed since the first virtualisation environments were created (on the x86 architecture) and probably in no time at all these technologies or similar will just work out of the box and be the norm.   In the meantime I am going to keep poking away and hope to finally get one of these environments working for me.

So if you read this and have some useful pointers I would be most interested in using them to get up and running.

Update: 2013-01-02

I see the OpenNebula work originally planned for Fedora 17 is now delayed (see:, but there are RPMs for CentOS 6 which can be found or built from here:!opennebula.git. So it looks to me as if it’s likely I will soon be able to get some packaged version of OpenNebula working on my CentOS 5 and Fedora 17 home PCs some time soon.  Still trying to make progress in the meantime.