Oversubscription What is Virtualization p p p Run
Oversubscription
What is Virtualization? p p p Run multiple OSes and user applications on the same hardware n e. g. , run both Windows and Linux on the same laptop How is it different from dual-boot? n Both OSes run simultaneously OSes are completely isolated from each other
Reduce costs by consolidating services onto the fewest number of physical machines
Non-Virtualized Data Centers p Too many servers for too little work p High costs and infrastructure needs n n n Maintenance Networking Floor space Cooling Power Disaster Recovery
Dynamic Data Center p p Virtualization helps us break the “one service per server” model Consolidate many services into a fewer number of machines when workload is low, reducing costs Conversely, as demand for a particular service increases, we can shift more virtual machines to run that service We can build a data center with fewer total resources, since resources are used as needed instead of being dedicated to single services
VM Workload Multiplexing Separate VM sizing VM multiplexing s 3 s 2 s 1 We expect s 3 < s 1 + s 2. Benefit of multiplexing ! n Multiplex VMs’ workload on same physical server
So, it is just like Java VM, right?
Two Types of Hypervisors (or VMM) p p p Hypervisor is a software layer that allows several VMs to run on a physical machine The physical OS and hardware called the Host VM OS and applications are called the Guest Type 1 (bare-metal) Guest Host Process VM 1 VM 2 Type 2 (hosted) Process VM 1 VM 2 Process Hypervisor OS Hardware VMware ESX, Microsoft Hyper-V, Xen Guest Host VMware Workstation, Microsoft Virtual PC, Sun Virtual. Box, QEMU, KVM
Bare-metal or Hosted? p p p Bare-metal n Has complete control over hardware n Doesn’t have to “fight” an OS Hosted n Avoid code duplication: need not code a process scheduler, memory management system – the OS already does that n Can run native processes alongside VMs n Familiar environment – how much CPU and memory does a VM take? Use top! How big is the virtual disk? ls –l n Easy management – stop a VM? Sure, just kill it! A combination n Mostly hosted, but some parts are inside the OS kernel for performance reasons, e. g. , KVM
Hypervisor or Docker? 19
VM on Multi-core CPUs p Each core can be configured for multiple VMs n A Quad-core CPU could be configured as a 32 node multi-computer n Limiting factor is often memory. Each guest OS has its own requirements (512 MB? ) 21
Installing a Virtual machine p Base OS is Windows 7 First install Sun Virtual. Box as hypervisor p Then, Guest OS will be Ubuntu 12. 04. 1 p 22
Installing Sun/Oracle Virtual. Box 23
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Installing Ubuntu VM 27
Installing Ubuntu VM 28
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