Tuesday, 4 January 2011

A third slice of V

Happy new year to one and all!

This post follows on from a previous item on virtualisation. We had installed the hardware, then the ESXi software - now to start getting serious.

ESXi does have a console to set-up certain key items, but these are very limited. Essentially, it allows you to change hostname, set IP addressing and some security, not much else. To manage the host machines, you have to use another piece of software; the VSphere Client which runs from a PC. I already had a copy of this installed on my laptop, from the tests that I had run earlier in the year. However, I decided to get the latest version so that we could start as we mean to continue.

The update went through quite quickly and after about 15 minutes, I had the logon dialog box. Put in the correct IP address and logon to the host; except that it came up with an "invalid user name or password" message. I checked the details and they were correct. I double checked the details; domain, username, password. They were definitely all correct. After having stared at this for a few minutes, I then realised that the host installation had used a US keyboard layout and I was inputting the details using a UK layout keyboard. When I re-entered the same details using the US layout, it let me access the host. And it appears that there is no UK layout option available on the host installation routine.

Looking at the details of the host, I could creat VMs and allocate resources; but this wouldn't allow me to manage the other hosts. To do this, I had to install the VCenter Server product and use to do all the management. The idea was that this would be installed on the first VM, but when I tried to install the software, it produced an error stating that it was not possible to install the server software on a VM. This made no sense; the material that I had received all indicated that the best practice would be to install the VCenter Server on a VM.

After some analysis, the solution became obvious; I had the wrong version of VCenter Server. I had downloaded it from the VMWare web site; once you get used to the site, it is quite sensibly laid out, but to start with, it can be a bit overwhelming. When I checked, there is a particular set of downloads to match the version of VMWare that we had purchased, and this was where I should have got the software from. So I downloaded that version; and yes, it installed straightaway.

So far, so good; I had the hosts running, the SAN was available and with the VCenter Server software installed, I could see all of the hosts and start to do some more detailed work. Unfortunately, we have a number of projects on the go at the moment, so I was involved in another one for a few days before I could get back to playing with the VMs.

When I did get back to the virtual platform, I wanted to make the storage on the SAN unit available. I was able to initiate the iSCSI connectors and these showed the disk allocation on the SAN unit. However, these were not available to the VMs; it needs a check box to be ticked for this to happen.

Later on, I realised that we still had an issue; although the storage area was available to VMs on the one host, it wasn't available to the others. Further checking revealed yet another setting (this time on the SAN itself) that needed to be checked, and as soon as this was done, each of the hosts could see all of the storage areas.

Unfortunately, I got this resolved after I had created the first VM and installed the VCenter Server. This means that the image and the virtual disk are actually stored in a local drive on the host server, which is not quite what was planned. It appears that this can't be moved using the VMotion process; but I may be able to get around this by using the P2V function at a later stage. If this works I'll write another piece about that later.

So at this point we had all of the hardware installed, all of the software licensed and running, our first VM created and some templates ready for future use. We can now manage the systems and have experiemented with copying, snapshotting, moving using the VMotion process, modifying resource allocation on VMs and deleting the various unwanted bits. It has taken a bit of time, but now there is a good level of confidence in the product and we are comfortable that we can move to the next level. And there will be more on that next time.