I have been studying fundamentals of cloud architecture lately and I am finding it difficult to understand the difference between a container and a virtual machine in Azure.
First I thought a VM has an operating system while containers don't since the are used to serve libraries then I don't know what to believe again. I need an explanation please.
Within each virtual machine runs a unique guest operating system. VMs with different operating systems can run on the same physical server—a UNIX VM can sit alongside a Linux VM, and so on. Each VM has its own binaries, libraries, and applications that it services, and the VM may be many gigabytes in size.
In production we're going to deploy a redis server and need to set the overcommit_memory=1 and disable Transparent Huge Pages in Kernel.
The issue is currrently we only have one giant server, and it is to be shared by many other apps. We only want those kernel configs in the redis server. I wonder if we can achieve it by spinning up a dedicated VM for redis. Doing so in docker certainly doesn't make sense. My questions is:
Will those Kernel configs take actual effect in the redis VM even if the host OS doesn't have the same configs? I doubt it since the hardware resource is allocated by the host machine in the end.
Will the kernel config in the redis VM affect other VMs that run other apps? I think it won't, just want to confirm.
To achieve the goal, what kind of VM or hypervisor should we use?
If there's no way to do it in VM, is having a separate server (hardware) for redis the only way to go?
If you're running a real kernel on a virtual machine, the VM should be able to correctly handle overcommitted memory.
The host server will grant a fixed chunk of memory to the VM. The VM should manage that memory as it sees fit, including overcommitting its own address space.
This will not affect other applications running on the host (apart from the fact that is has less memory available). If it does, there is a problem with your hypervisor.
This should work with any Hypervisor. KVM is a good place to start.
Note that I have not actually tried this -- experiment results are welcome!
I have successfully installed RedHat Linux and run them on harddrive using VMware simulation. Things work quite smooth if I put all the nodes VM on my physical machine.
For management purposes, I want to use USB devices to store ISO and plug one if more nodes are needed. I would like to run VMware on my physical machines.
Can I just build one virtual machine on one USB device? So I can plug one node if needed.
I mean, if I simulate machine A one USB 1 and another machine B on USB 2, can I build a network using my physical machine as server?
(1) If so, are there problems I should pay attention to?
(2) If not, are there any alternative solution for my management purpose?(I do not want to make VMs on partitions of my physical machine now) Can I use multiple mobile hard drives instead?
Actually I want to start up master-slaves Hadoop2.x deployments using virtual machines. Are there any good reference for this purpose?
I shall explain that am not too lazy to have a try on my idea, however, it is now rather expensive to do so if I do not even know something about the feasibility of this solution.
Thanks for your time.
I'm not an expert on VMWare, but I know that this is common on almost any virtualization system. You can install a system :
on a physical device (a hard disk, a hard disk partition)
or on a file
The physical device way allows normally better performances since you only use one driver between the OS and the device, while the file way offer greater simplicity to add one VM.
Now for your questions :
Can I just build one virtual machine on one USB device? Yes, you can always do it on a file, and depending on host OS directly on the physical device
... can I build a network using my physical machine as server? Yes, VMWare will allow the VM to communicate with each other and/or with the host and/or with external world depending on how you configure the network interfaces of your VMs.
If so, are there problems I should pay attention to?
USB devices are pluggable and unpluggable. If you unadvertantly unplug one while the OS is active bad things could happen. That's why I advised you to use files on the hard disk to host your VMs.
memory sticks (no concern for USB disks) support a limited number of writes and generally perform poorly on writes. Never put temp filesystem of swap there but use a memory filesystem for that usage, as is done for live filesystems on read-only CD or DVD
every VMs uses memory from the host system. That is often the first limitation for the number of simultaneous VMs on a personnal system
i am trying to measure code performance (basically speed-up when using threads). So far i was using cygwin via windows or linux on separate machine. Now i have the ability to set up a new system and i am not sure whether i should have dual boot (windows and ubuntu) or a virtual machine.
My concern is whether i can measure reliable speed up and possibly other stuff (performance monitors) via a linux virtual machine or if i have to go with with normal booting in linux.
anybody have an opinion?
If your "threading" relies heavily on scheduling, I won't recommend you to use VM. VM is just a normal process from the host OS's point of view, so the guest kernel and its scheduler will be affected by scheduling by the host kernel.
If your "threading" is more like parallel computation, I think it's OK to use VM.
For me, it is much safer to boot directly on the system and avoid using a VM in your case. Even when you don't use a VM, it is already hard to have twice the same results in multi-threading because the system being used for OS tasks, so having 2 OS running in the same time as for VM even increases the uncertainty on the results. For instance, running your tests 1000 times on a VM would lead to, let's say, 100 over-estimated time, while it would maybe be only 60 on a lonely OS. It is your call to know if this uncertainty is acceptable or not.
We have a physical machine that runs VMware and hosts a VM we use for SharePoint deployment testing. That machine is old and dying, and my employer's network czars are heavily pushing hosted VMs as a replacement for outdated physical servers. I was curious about whether it's possible to run VMware inside VMware, and if so, whether there are severe performance implications. We don't require extreme performance from this setup, since it's just used for SharePoint testing and the associated SQL Server is on a different box. My guess is that we can't just use the primary hosted VM for our testing because we'll want to roll back occasionally and otherwise have more control over it, and getting buy-in for that from the network folks is unlikely. Does anyone have any experience with this?
edit: I know this nesting certainly isn't the preferred option, but (1) we want the flexibility of being able to use VMware snapshots at will and (2) the network folks will not allow us to arbitrarily roll back to a previous point in time because of the potential for removing mandated security updates. My guess is that a local desktop machine running VMware Workstation might just be the way to go. The hosted option seems attractive if it will work though since it's less machine maintenance for me to deal with.
The technical limitation with running VMware inside VMware is that VMware, Virtual PC, etc takes advantage of the Virtualization features present in modern CPUs.
If you have two or more hypervisors are both trying to control Ring 0 then there will be problems, this is something that I've encountered while trying to run both VMware and Virtual PC simultaneously on my desktop - one will error out/crash.
If your hypervisor can interact with the 'parent' hypervisor, then you'll be OK. Alternatively if the child hypervisor doesn't try to use the CPU virtualization features, or entirely emulates the CPU (such as QEMU) then you should also be OK.
Basically old-style hypervisors on old CPUs use Full virtualization (slow) which would be capable of nesting with a heavy, heavy performance hit. modern Hypervisors/CPUs use hardware assisted virtualization (near native performance) and you'd be hard pressed to find a hypervisor that is designed or capable of nested virtual machines.
Finally, I'd really advise against running dev/test VMs on the same physical server that is running production VMs. There's just too much to go wrong and security implications - you need to manage the dev/test environment and it sounds like you shouldn't have access to production environment. Likewise you probably don't want the operations team messing about with your test environment.
UPDATE: ESXi 4 now supports virtualizing itself. See this article for more information
I've never run VMware in VMware, but I've run VirtualPC inside VirtualBox without problems, so there's no fundamental reason it shouldn't work I suppose...
It sounds to me more like you have a problem with the inflexibility of your "network czars" than any technical one. If you're a developer or QA you need a testing environment where you can fool around with outdated (and potentially insecure) versions of the OS and applications, without putting the rest of the company network at risk.
Ex-VMware employee here.
Firstly, when you say Nested VMware I will assume you mean Nested ESXi. (You could also mean Workstation, Fusion, or Player).
Nested ESXi environments are unsupported and should not be used for production. These scenarios are not tested in QA and not guaranteed to work. In short, if you experience any kind of problem, VMware will not help you with this Nested ESXi setup.
With that said, yes you can do it and yes it does work. A lot of people use nested ESXi in their labs but not in production. Previously there were special configuration file edits that were necessary for nested ESXi to work. I have seen environments with even 3 layer nested ESXi servers (ESXi vm on and ESXi vm on a physical ESXi host). More recently there is the ESXi appliance which makes this much easier.
Have a look here:
http://www.virtuallyghetto.com/2015/12/deploying-nested-esxi-is-even-easier-now-with-the-esxi-virtual-appliance.html
I ran into this same problem. I work at a large company where our entire infrastructure is virtual, so if you need a server you get a VMware VM. So I had a couple of Windows 2003 Server Standard Edition based Guest VM's that had 6GB of memory and 200 GB of disk space, but I wanted to run linux and a LAMP stack on them. So I tried to install VMware Workstation on one and I got an error message saying it couldn't be installed within a VM. I also tried Microsoft Virtual PC and got a similar error message. I installed Sun's VirtualBox and that installed fine, but I couldn't get the networking to work w/in the guest Ubuntu OS. My next step is to try QEMU although performance might become an issue.
You ought to have a look at Mainframes - they are Virtualised from the word go:
Hardware - runs Hypervisor Type 1 - Level 1
on this you have zVM - Type 2 Hypervisor - Level 2
on this you have zOS - your main big operating system - Level 3
and/or
on this you have zLinux - Level 3
and/or
on this you have zVM for testing next version - Level 3
and/
on this you have zOS for testing zVM plus zOS both at next version - Level 4
So going down to level 4 is pretty common
Mind you on a Mainframe you can have 1000's of VMs running at the same time - and most sites who start using zVM/CMS and zVM/Linux usually do.
I can see two solutions for this (three if you count a VM inside a VM which is just crazy).
New hardware, which should be robust enough to handle several VM's used specifically for testing (sharpoint, etc.). In this situation your team could be given more rights without affecting non-testing VM's.
Sharepoint test VM's are moved to the main VM pool and those who need access are given the ability to checkout/deploy/rollback testing resources. This could be direct through VMWare tools or through an internal project that works through a VMWare API.
This should be a joint decision between Network/Dev/Testing.
JFYI:
I tried installing and running VMware ESXi server host(child ESXi server) as a virtual machine(on parent ESXi server) and it runs however you can not run any VMs under child ESXi server.
I am doing practice of VMware vSphere Data center virtualization on single Physical machine. There is VMware Workstation installed on Windows 8 OS. In VM Workstation, I have installed Windows Server 2008 OS, VMware ESXi OS and created the VMware Data center LAB. There is VMs running in LAB, and its confirm that We can user VMware in VMware. But it depends on your need, and Products which is chosen.
You can install ESXi on VMware Workstation, it's usefull to learn ESXi, so there in no reason run VMware in VMware.
Yes. You can run VMWare inside VMWare. Though its not officially supported, You can deploy VMs in the child ESX. I have checked for an advanced feature like PassThrough the HBA card but which was not available in child ESX, hence I could not provide a LUN from array.
So in production its better to not use this.
But for training and practices this can be used.
You can do that.
You can install vmware esxi inside virtual machine of another vmware esxi.
But the performance will be very bad.
Totally works.. totally can't do it other then for some kinda testing or some kind of educational purpose, because you won't get support. and from my limited experience it doesn't perform that well.
Yes, you can, VMware can even detect if it's running inside of another vmware machine and warn you that VMception will cause worse performance. which it will, trust me, just try to get the version the virtual machines work best in a physical machine, as to get as much performance possible.
"whether it's possible to run VMware inside VMware" What?
I can run Windows with Sharepoint in a VMWare machine that's hosted somewhere.
Or, I can run Windows with Sharepoint in a WMWare machine that's actually a VMWare machine that's hosted somewhere.
Why on earth would I add a level of nesting? Why not just go with Windows with Sharepoint hosted somewhere?
You can have any number of VMWares running on a single host. Lots of different versions doing lots of different things.
Nesting them doesn't make sense.