Virtualisation tutorial

[Skinny]

I've only ever used workstation virtualisations for teaching myself/trying new things on my own computer. I've used vmware, micro$haft and currently using virtualbox. I'm not great when it comes to server virtualisation though, never done it. Can anyone point me in the right direction of any good tutorials?

[gaz350]

good video for zenserver

 

Created with Camtasia Studio 5

[Guest theeldergeek]

I've only ever used workstation virtualisations for teaching myself/trying new things on my own computer. I've used vmware, micro$haft and currently using virtualbox. I'm not great when it comes to server virtualisation though, never done it. Can anyone point me in the right direction of any good tutorials?

 

I'd just be happy to understand virtualisation, period.

 

I really don't have much idea what it is, how it works, which software to use, or how to set it up.

 

An "idiots guide" would be good.

[synaesthesia]

Grab yourself a 30 day demo of VMWare Workstation, or indeed Virtualbox.

 

In laymans terms, you install, lets use VMWare WS as an example. You run the program and create a new Virtual Machine.

This is the software equivalent of building a PC. You tell it how many processors you want to give it, how much memory, how large a disk drive (taken from your main drive obviously) and any other hardware. You can tell it to use a physical CD Rom or an ISO Image of a CD/DVD instead.

So, we point it to an ISO - Windows Server 2008.iso for instance. Power on the Virtual Machine, and you'll be greeted with something that looks not too much different to a typical PC. It has a "bios" in which you can tweak some settings, change boot orders and what not.

It boots from the "CD" and off it goes, installing Windows 2008 in the same way as a normal PC.

It goes through the process, and at the end we have a working Virtual PC. You can connect USB devices to it (which disconnects them from the "host" PC), use the systems sound card, additional hard drives, optical drives - anything you want.

 

It's really that simple. You can go quite advanced even with the workstation version. It'll be worth grabbing something just to have a play - they can be extremely useful for sandboxing, general testing etc. I use one on site with me to build RM packages without the hassle of clean machines.

[FragglePete]

I'd just be happy to understand virtualisation, period.

 

I really don't have much idea what it is, how it works, which software to use, or how to set it up.

 

An "idiots guide" would be good.

 

I was in a similar situation about a year back, didn't really understand it all.

 

But, to give you an idea, we installed a new server last Summer; Compaq G5 and crammed it with 16Gb of RAM and a load of dual port hard drives. Downloaded and installed XenServer which is free for production use. Then, using the XenConsole divided this machine into 4 seperate virtual boxes allocating the appropriate number of CPUs, Memory and Storage for the task of each virtual servers. Micosoft Licensing allows you to install up to four servers with one copy of Server Enterprise on a Physical Box.

 

The box has performed flawlessly over the past year, we've got it working as the main home file store, a secondary Domain Controller, the main Print Server and a 'management' server looking after AV updates and WSUS. Monitoring the box during first morning logins and end of day logouts shows that the whole machine peaks at about 18% of capacity during these periods. The network cards are the hardest hit during these times, but it does not even break into a sweat.

 

CSE did the install for us last summer, and I'm looking to get another in this year to retire some of the older physical boxes. Then later on start looking to add SAN storage to this lot as well as we will be hitting capacity by then.

 

Hope that helps.

 

Pete

[Guest theeldergeek]

Grab yourself a 30 day demo of VMWare Workstation, or indeed Virtualbox.

 

I downloaded and installed VMware Player on my Windows 7 box, then installed Ubuntu. It all works except for clicky sound when playing MP3's, YouTube etc.

 

So what do I do with it now

 

I can see it being useful in a server environment where you might want different controllers doing different things, but for me at home, I don't have anything I can think of that I would want to use it for.

 

Everything I need to do I can do on my Win7 box.

 

I'll have a play around with Ubuntu for a bit, but I'm sh1te at command line stuff, SUDO this and CHMOD that!

[vikpaw]

I'd just be happy to understand virtualisation, period.

 

I really don't have much idea what it is, how it works, which software to use, or how to set it up.

 

An "idiots guide" would be good.

 

synaesthesia has it down basically.

i use VMWare Server, it's free to use, just install it on any PC running windows.

 

If you run on a desktop, it does steal some of the power away from your machine, so best to put it on a separate box that you don't want to use at the same time.

 

You can control the virtual machine(s) via a web page, and it even comes with it's own remote desktop client that you can download. I assume VMWare Workstation does the same.

 

I've used it for some time now to virtualise my SIMS setup, so i can test updates. I recently put the same software onto a new blade server we bought so i can utilise the extra power.

 

VMWare Server is free, but it's not as easy to make backups of your system. These are called snapshots and it's like system restore except it restores, system, hdd, memory the works back to a fixed point in time. VMWare server only allows 1 snapshot, VMWare fusion for the MAC allows multiple snapshots as do most paid for products.

 

The downside with this approach is that you are still running an underlying OS which comes with it's own pitfalls and caveats.

 

We are now looking into using a more robust system, using Microsoft Hyper-V. This comes in a version that involves installing a cut down version of Windows, and a bare metal version where you just install the basics, enough to boot and setup another virtual machine.

[vikpaw]

I downloaded and installed VMware Player on my Windows 7 box, then installed Ubuntu. It all works except for clicky sound when playing MP3's, YouTube etc.

 

So what do I do with it now

 

I can see it being useful in a server environment where you might want different controllers doing different things, but for me at home, I don't have anything I can think of that I would want to use it for.

 

Everything I need to do I can do on my Win7 box.

 

I'll have a play around with Ubuntu for a bit, but I'm sh1te at command line stuff, SUDO this and CHMOD that!

 

It's useful for testing different operating systems, without having to blow away your main machine.

You could use it to run a virtual XP / Vista box if you had software that wasn't yet Windows 7 enabled, maybe a game or something.

It's also a safe area to test new software as the virtual machine is essentially sandboxed and you can corrupt the registry all you like with random install / uninstalls and your main machine wont suffer.

Kubuntu is nice, better than ubuntu, also maybe look at edubuntu. it doesn't just have to be command line stuff, the GUI is pretty good.

[garethEds]

This XenServer looks very interesting. Like others the most I get out of virtualisation is running Parallels Desktop for Mac.

 

Something to look into I think.

 

Gareth

[cookie_monster]

This XenServer looks very interesting. Like others the most I get out of virtualisation is running Parallels Desktop for Mac.

 

Something to look into I think.

 

Gareth

 

 

 

We bought 2 Sun x4150s and a 7110 SAN last summer, we virtualised almost our entire Windows 2003/2008 infrastructure on Xenserver 5.5. It's been rock solid so far I can recommend it as a budget virtualisation solution.

[john]

We bought 2 Sun x4150s and a 7110 SAN last summer, we virtualised almost our entire Windows 2003/2008 infrastructure on Xenserver 5.5. It's been rock solid so far I can recommend it as a budget virtualisation solution.

I would agree with what you have done, just looking at doing the exact same thing, well different Oracle servers as the X4150s seem to have gone now (guess they have gone EOL). But I will be using my 7110 for the storage of the VMs.

 

Out of interest what spec 4150s do you have? I was thinking of using 4 hosts but if you used 2 I may get away with less but a slightly higher spec in them perhaps?

[Soulfish]

I would agree with what you have done, just looking at doing the exact same thing, well different Oracle servers as the X4150s seem to have gone now (guess they have gone EOL). But I will be using my 7110 for the storage of the VMs.

 

Out of interest what spec 4150s do you have? I was thinking of using 4 hosts but if you used 2 I may get away with less but a slightly higher spec in them perhaps?

 

Our 4 x4150's are 2 x Intel E5450 3.0Ghz quad-core Xeons with 32gb Ram. No problems with CPU usage and RAM usage runs at about 50-60% on all servers with the majority of our services virtualised.

[synaesthesia]

One *fantastic* use I've done a couple of times is the ability to test on your servers - without breaking your servers.

 

For instance, I want to attempt something big on a CC3 server. I don't want downtime for the sake of the school, and it's just something I want to do. It may work, it may not.

 

So, use Acronis True Image to take a full image of the server, pop it on a USB drive. Make a VM, and restore the image to said VM using Universal Restore (similar to symantec BESR if you've not used it - similar & better IMO, using that can half the migration time from one server to another if you need to do it like that).

 

Identical software environment for testing with.

[garethEds]

One *fantastic* use I've done a couple of times is the ability to test on your servers - without breaking your servers.

 

For instance, I want to attempt something big on a CC3 server. I don't want downtime for the sake of the school, and it's just something I want to do. It may work, it may not.

 

So, use Acronis True Image to take a full image of the server, pop it on a USB drive. Make a VM, and restore the image to said VM using Universal Restore (similar to symantec BESR if you've not used it - similar & better IMO, using that can half the migration time from one server to another if you need to do it like that).

 

Identical software environment for testing with.

 

Is there a cost with Acronis True Image?

 

I guess one of the advantages is backups of your virtual machines.

 

Gareth

[Skinny]

I guess the things I don't understand or want more info on are: I'm not sure about hardware requirements to run it without it seeming sluggish. I'm also concerned about putting all the eggs into one basket so to speak, because the whole OS and everything on it is stored as a single file what if the underlying system went t1ts up? If I had multiple virtual machines running I'd lose them all.

 

I've also thought about using it on client machines because I only work in primary schools and they all have different hardware. At the minute each school has a ghost image per build, I'm trying to get autoinstalls or find ways of rolling out the software automatically and just have smaller images with the OS and updates on which I'm making good progress with but it occurred to me that I could create virtual machines instead. But as I said earlier, I'd just like to know more. Wikipedia is good source though.

[tmcd35]

I guess the things I don't understand or want more info on are: I'm not sure about hardware requirements to run it without it seeming sluggish. I'm also concerned about putting all the eggs into one basket so to speak, because the whole OS and everything on it is stored as a single file what if the underlying system went t1ts up? If I had multiple virtual machines running I'd lose them all.

 

I've found the trick with virtualisation is to just treat each VM as if it was it's own physical machine. If you were to go out and purchase a physical server to do that job what spec it would be? Then that is the spec the VM should be. How meny VM's do you want to run on the host? Tot up the total spec's of all the VM's you want to run on the host and you get an idea of processor power and memory requirements for the host.

 

It's cheaper buying one physical server with 8-cores and 16Gb ram to run 4 VM's than it is to buy four physical servers each with 2-cores and 4Gb Ram.

 

There's a little more to it than that - %age of cpu time each VM is idle (how much cpu power is really needed), and which VM archtecture you use (VMware is better than Hyper-V at memory allocation) - but essentially that's it.

 

As for eggs in one basket. Thats the old risk assessment/cost-benefit trade off. Redundancy plays a part. Two host servers in stead of one, each able to take up the slack if the other fails. SANS/NAS storage so multiple hosts can get access to all the VM images.

 

Then you look at redundacy is the SAN/NAS environement as a single point of failure and Disaster Recovery plans. How you back up the VM's, how often you do it and how easy it is to restore those backups.

Edited February 21, 2010 by tmcd35

[Guest Guest]

1 putting all the eggs into one basket

2If I had multiple virtual machines running I'd lose them all.

 

3I've also thought about using it on client machines... ghost image per build, I'm trying to get autoinstalls or find ways of rolling out the software automatically

 

1 Yes you are and thats why people tend to go for virtual pools and (clustered) SANs when doing that sort of thing.

 

2. Yes they'll all die, but the beuty of VMs is they only need a specific underlieing host OS, rather than specific hardware which could potentially be impossible to find if your server is old. You simply build a new host server and import the backed up VMs. Over 2 days i managed to import 14 VMs, id hate to imagine how much of a PITA it would have been with physical servers!

 

3. Decktop VMs are a bad idea unless you are willing to go the whole hog and go with the likes of xenapp. Your OS and app depolyment is a totally seperate issue to virtualisation imo. Have a look at Autoimage (roguespears)and driverpacks.net for OS deployment. And building MSIs for apps.

 

I have XP as a universal image for any and all PCs. And MSIs and scripts for all our software. Just netboot a PC, type in my password, give it a name and put it in a group. Come back an hour or so later and its ready to go.

[Skinny]

Good answers, confirming what I suspected. I work alone most of the time and sometimes doubt my own figuring so it's good to see what others are doing. Cheers.

 

I haven't seen autoimage i'll look into it, I'm just messing around with installrite at the minute and ghostAI plus autoIT.

I have XP as a universal image for any and all PCs. And MSIs and scripts for all our software. Just netboot a PC, type in my password, give it a name and put it in a group. Come back an hour or so later and its ready to go.

That's where I want to be. Unfortunately there is so much varying software in the schools and most of it is designed for Win95 (no MSI's) and the like that it will take me ages to sort through plus I only get 3 hours per fortnight in each school so it's a slooooow process.

[synaesthesia]

Yeah there's cost to Acronis - I've been told things like Clonezilla might actually be able to do the same thing but I've yet to experiment

 

You can decrease some of the problem areas with VM's by allocating physical hardware too - i.e. a separate HDD or even array of HDD's for each VM if you really wanted to - true they'll still be dependant on the host OS but there's many ways of setting it up to complete the tasks you need.

 

Are they usable/feasible in a production environment? Too right - you can get a bloody good server together, make use of things like ESX/GSX (can't remember which is which tbh!) and run 2 or more virtual servers side by side - allocate separate drives and even processors/threads to each one - I've only seen this being done once a while ago for a top flight motorsports team and I was amazed at the level of performance they were getting out of it - and the amount of hard work it was doing. Normally they'd have needed a rack full of machines to get the best from it however for portability reasons this was a real cost saver without the lack of performance.

 

I've often wondered about smaller site schools using them - for instance an MIS server and curriculum server running on the same hardware, virtualised. Could be quite cost effective.

[Theblacksheep]

 

So, use Acronis True Image to take a full image of the server, pop it on a USB drive. Make a VM, and restore the image to said VM using Universal Restore (similar to symantec BESR if you've not used it - similar & better IMO, using that can half the migration time from one server to another if you need to do it like that).

 

You could just 'convert' the server to a VM too.

[cookie_monster]

I would agree with what you have done, just looking at doing the exact same thing, well different Oracle servers as the X4150s seem to have gone now (guess they have gone EOL). But I will be using my 7110 for the storage of the VMs.

 

Out of interest what spec 4150s do you have? I was thinking of using 4 hosts but if you used 2 I may get away with less but a slightly higher spec in them perhaps?

 

 

 

 

Our 2 x4150's are 2 x Intel E5450 3.0Ghz quad-core Xeons with 20 gb Ram. I've got 4 VM's on each. 2 busy fileservers, 2 DC's, a web/print/wsus server, a Citrix gateway server and a Citrix Xenapp box and another couple doing bits and bobs. The x4150s seem to cope really well i've never seen the CPU get over 30% so far. The SAN seems to cope well also i've got 3 NICs in an LACP bond for iSCSI and although it gets busy i've never seen it struggle to cope.

[vikpaw]

...

There's a little more to it than that - %age of cpu time each VM is idle (how much cpu power is really needed), and which VM archtecture you use (VMware is better than Hyper-V at memory allocation) - but essentially that's it.

...

 

This is one of the key benefits of virtualisation, if you use correctly configured software, you can have 4 VMs each with 4GB RAM but only have 12GB RAM on the physical hardware. but you get the idea. Ditto CPU usage. The Virtualisation software is essentially a powerful resource handler.

 

Not only do you get cost savings by only buying one server to host many, but in theory the spec doesn't have to be the sum of the parts you would need in a physical environment. Factor in the ability to buy one support contract over 3, possibly a better level, and it makes real sense to go down this route.

 

As for other issues. VMWare has a converter that lets you freely convert between different versions / host systems including non-VMWare files. Also, you can do a physical to virtual conversion so you don't necessarily need to use the backup/restore method.

 

I clone machines really quickly by just copying the file to another host and then open it up. So that potential single point of failure is actually remarkably easy to restore. Now if it's on a SAN in a raid config, that gives you fault tolerance.

 

We are planning our deployment now, for a Sharepoint setup and i plan to use at least 2 Blade servers, rigged up so that 1 will take up the slack if i ever need to reboot the other (or the guests it is hosting). Hopefully we'll soon add a couple more blades to help ease the load. The blades are dual quad-core Xeons 3ish GHz, 12GB RAM per blade. Each has one dedicated drive and the rest is shared storage. Initially thinking of 3 VMs per blade, but if it goes well more....

[tmcd35]

This is one of the key benefits of virtualisation, if you use correctly configured software, you can have 4 VMs each with 4GB RAM but only have 12GB RAM on the physical hardware. but you get the idea.

 

I was avoiding that example It's one of the key differences between VMWare and Hyper-V. With Hyper-V if you want 4Gb of ram for 4VM's you'll need atleast 17Gb on the host - 4Gb for each VM + some RAM for the host.

 

VMWare allows you to over commit the memory. It does this in a number of ways - firstly by realising that it's rare that any one VM, let alone all 4 (in this example) will max out thier 4Gb allocation. It also monitors what's being run in the VM's. All four running the exact same version of Windows? not a problem, only one copy of the various library files, etc needs to be loaded into ram for all four copies to share.

[vikpaw]

I was avoiding that example It's one of the key differences between VMWare and Hyper-V. With Hyper-V if you want 4Gb of ram for 4VM's you'll need atleast 17Gb on the host - 4Gb for each VM + some RAM for the host.

 

VMWare allows you to over commit the memory. It does this in a number of ways - firstly by realising that it's rare that any one VM, let alone all 4 (in this example) will max out thier 4Gb allocation. It also monitors what's being run in the VM's. All four running the exact same version of Windows? not a problem, only one copy of the various library files, etc needs to be loaded into ram for all four copies to share.

 

That's a useful Heads UP, i'm evaluating Hyper-V at the moment. I was under the impression that the stand-alone, bare metal version didn't have any major overhead....?

 

I also, wasn't aware that it wont do smart memory management. I assumed they all do that. Luckily our blades are RAM rich, but i'm starting to rethink and go down the ESXi route, just need to fine a decent GUI based manager. Ideally a free one...i think there's a thread on that somewhere.

[tmcd35]

You need to remember Hyper-V isn't quiet as bare metal as ESX. It's a little more like Xen on Linux. It needs a primary copy of Windows to run with. So you have the overheads associated with running an additional copy of Windows. Maybe less than the 1Gb I quoted above - maybe 256mb - but essentially you need ram for all your VM's and the host.