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 VirtualBox on my Windows 7 machine, and recently installed a Redhat linux VM. I'm planning to learn linux programming with some low-level stuff, such as kernel function calls and assembly.
My question is: is my Redhat VM a "real" linux environment for my purpose? I guess that whatever I do in the VM is done in a "linux simulator" in VirtualBox, and under the hood the "linux simulator" still does its job using functionalities provided by the Windows host (e.g. Windows function calls). Is this true?
VirtualBox is not a "Linux simulator", it is a "computer simulator". OS selections within such an simulator are for the purpose of deciding which virtual devices to make visible, and not for running a different simulator "core".
I think you should dual boot linux instead of VM because not only it saves resources ("Prevent Computer from going slow") But also give you better functionality and hardware support
Edit:
and you can also use Live Cd(also usb)
I have access to a machine to which I can ssh. How to determine if my OS is running in fully-virtualized (where VMM does binary translation), para-virtualized or non-virtualized environment? I have some idea of how to go about it (some operations like accessing a memory page/disk will take longer time in a virtualized environment) but don't know how to proceed.
It does depends on the VMM you are running on top of. If it's a Xen or Microsoft VM, I believe CPUID with EAX value of 0x40000000 will give you a non-zero value in EAX. Not sure if that works on VMWare, VirtualBox or KVM. I expect that it will work there too...
Measuring access time is unlikely to ALWAYS show you the truth, since in a non-VM system those can vary quite a lot as well, and there is no REAL reason that you'd see a huge difference in an efficient implementation. And of course, you don't know if your VM is running with a REAL hard-disk controller passed through via the PCI, or if your NFS mounted disks are connected via a REAL network card passed through to the VM, or if they are accessed through a virtual network card.
A good VMM shouldn't show you much difference as long as the application is behaving itself.
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.
Is there a way to figure out if a win 2003 server server you are connecting to is virtualised? I tried asking but not 100% sure of the answer is correct.
This is a duplicate of this question: How to identify that you’re running under a VM?.
Quoting from the accepted answer to that question by JawnV6:
The classic trick to detect a VM is to populate the ITLB, run an instruction that must be virtualized (which necessarily clears out such processor state when it gives control to the hypervisor), then run some more code to detect if the ITLB is still populated. The first paper on it is located here, and a rather colorful explanation from a researcher's blog is located here.
I guess looking at the Device Manager (Control Panel | System | Hardware | Device Manager) should give you a good idea.
On one server, running on VMWare ESX, I see the following tell-tale signs of a virtual machine:
System Devices: VMware server memory controller
Network adapters: VMware Accelerated AMD PCNet Adapter
Mice: VMware Pointing Device
Disk drives: VMware Virtual disk SCSI Disk Device
A simple test that detects a VMware network adapter, is:
ipconfig /all | grep "VMware Accelerated"
(would perhaps also detect a host running VMware workstation)
Here's a decent explanation. You can check the manufacturer of a piece of hardware from WMI or within Device Manager to determine if it's a physical device or not.
http://blogs.msdn.com/virtual_pc_guy/archive/2005/10/27/484479.aspx
Can you tell us any more about how you're connecting to this server?
This depends on a couple of factors.
Are you using remote desktop to connect to the server and can you gain access to system files and folders?
Do you know what type of virtualization software is running the server?
Without know that information this question may be a litle difficult to answer correctly. There are a large number of virtualization software vendors and each of them have different setups that are in the virtual servers.
Without more information, the short answer is no. To the actual guest operating system it looks and acts like an operating system that is running on bare metal.
You could look for support software installed, for instance VMware usually installs VMware Tools on the guest operating system.