If you don't have an account on a grid-ready cluster, don't worry - this section will show you how to create a Virtual Machine (VM) that will, essentially, act as a grid User Interface (UI) within whatever operating system you happen to be using at the moment. We will do this using the CernVM service, and create a guest CernVM on your host system. There are a number of reasons to do this:
All you need to provide is the RAM and the hard disk space on your local host machine.
|If you already have access to a user account on an SL6 terminal, for example on a university computing cluster, you can probably skip this section.|
To create and configure a CernVM that will meet our needs, you will need to:
Let's look at each of these stages in a bit more detail.
You can find a list of compatible virtualisation software solutions on the CernVM image download page here. It doesn't really matter which you use but we've had success with this version of VirtualBox (Windows 7).
|This is the one bit that's a bit tricky for us to support - how you do this will depend on your local machine and its setup. Remember, search engines and StackOverflow are your friends here.|
Depending on the virtualisation solution you picked (and got working) above, download the baseline CernVM image file from here.
|At the time of writing (October 2015), the latest version was CernVM 3.5.1.|
Then use your virtualisation software to create a new VM from the downloaded image. You should be able to find instructions for how to do this from your virtualisation software provider. Use as much RAM as you can spare (up to about half of your host machine's total RAM) and use a virtual hard disk of about 30 GB.
Once you have created your CernVM, but before you start it, you will need setup the contextualisation for your CernVM.
The CernVM service offers the ability to contextualise a CernVM with pre-defined settings, environment variables, etc. that are put in place when the CernVM is first booted. This is known as pairing the VM. You can create your own contextuallisations, but it is also possible for individuals to create public contexts (e.g. for LHC experiments, open data initiatives, etc.) that anyone can use.
We have created such a context for GridPP. You can use it to get going with the Grid. Importantly, you do not need a CERN account to do this, so it is possible for anyone with a grid certificate to use it!
To pair your local CernVM with the GridPP context:
gridppto log in to your CernVM.
And that's it! You now have a shiny new GridPP CernVM from which you'll be able to access the Grid.
We'll be using
git (and GitHub) to access various
pieces of code and scripts. The CernVM comes with
installed but you'll need to configure it with your
username and email address. This can be done with
the following commands:
$ git config --global user.name "Ada Lovelace" $ git config --global user.email email@example.com
Before we move on, it's important to note that you will need to be able to access the hard disk of your host machine from that of your guest CernVM. This is so that you can move any files that you need across to the CernVM - most importantly, your Grid certificate file.
|With VirtualBox, for example, this is achieved using the Shared Folders functionality.|
Before proceeding, you should make sure that you can access the parts of your local hard disk that contain any software or data that you want to copy across.
Let's review what we've done with the checklist.