A virtual kernel architecture (vkernel) is an operating systemvirtualisation paradigm where kernel code can be compiled to run in the user space, for example, to ease debugging of various kernel-level components,[3][4][5] in addition to general-purpose virtualisation and compartmentalisation of system resources. It is used by DragonFly BSD in its vkernel implementation since DragonFly 1.7,[2] having been first revealed in September 2006 (17 years ago) (2006-09),[3][6] and first released in the stable branch with DragonFly 1.8 in January 2007 (17 years ago) (2007-01).[1][7][8][9] The long-term goal, in addition to easing kernel development, is to make it easier to support internet-connected computer clusters without compromising local security.[3][4] Similar concepts exist in other operating systems as well; in Linux, a similar virtualisation concept is known as user-mode Linux;[10][7] whereas in NetBSD since the summer of 2007, it has been the initial focus of the rump kernel infrastructure.[11]
The virtual kernel concept is nearly the exact opposite of the unikernel concept — with vkernel, kernel components get to run in userspace to ease kernel development and debugging, supported by a regular operating system kernel; whereas with a unikernel, userspace-level components get to run directly in kernel space for extra performance, supported by baremetal hardware or a hardware virtualisation stack. However, both vkernels and unikernels can be used for similar tasks as well, for example, to self-contain software to a virtualised environment with low overhead. In fact, NetBSD's rump kernel, originally having a focus of running kernel components in userspace, has since shifted into the unikernel space as well (going after the anykernel moniker for supporting both paradigms).
The vkernel concept is different from a FreeBSD jail in that a jail is only meant for resource isolation, and cannot be used to develop and test new kernel functionality in the userland, because each jail is sharing the same kernel.[7] (DragonFly, however, still has FreeBSD jail support as well.[7])
In DragonFly, the vkernel can be thought of as a first-class computer architecture, comparable to i386 or amd64, and, according to Matthew Dillon circa 2007, can be used as a starting point for porting DragonFly BSD to new architectures.[12]
DragonFly's vkernel is supported by the host kernel through new system calls that help manage virtual memory address space (vmspace) — vmspace_create() et al.,[3][9][13] as well as extensions to several existing system calls like mmap's madvise — mcontrol.[9][14][15]
^ abJeremy C. Reed, ed. (2007-02-10). "Answers from Matt Dillon about DragonFly's virtual kernel". BSD Newsletter .com. Reed Media .net. from the original on 2007-02-24.
^Daniel Lorch (2009-06-10). "Porting the HAMMER File System to Linux" (PDF). UML runs the Linux kernel as a userspace process, analogous to DragonFly BSD's virtual kernels … allow for a quick recompile-restart cycle and can be debugged easily with standard gdb.
Daniel Lorch (June 10, 2009). "Porting the HAMMER File System to Linux" (PDF). github.
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A virtual kernel architecture vkernel is an operating system virtualisation paradigm where kernel code can be compiled to run in the user space for example to ease debugging of various kernel level components 3 4 5 in addition to general purpose virtualisation and compartmentalisation of system resources It is used by DragonFly BSD in its vkernel implementation since DragonFly 1 7 2 having been first revealed in September 2006 17 years ago 2006 09 3 6 and first released in the stable branch with DragonFly 1 8 in January 2007 17 years ago 2007 01 1 7 8 9 The long term goal in addition to easing kernel development is to make it easier to support internet connected computer clusters without compromising local security 3 4 Similar concepts exist in other operating systems as well in Linux a similar virtualisation concept is known as user mode Linux 10 7 whereas in NetBSD since the summer of 2007 it has been the initial focus of the rump kernel infrastructure 11 vkernelOriginal author s Matthew DillonDeveloper s DragonFly BSDInitial releaseDragonFly BSD 1 8 30 January 2007 17 years ago 2007 01 30 1 2 Repositorysys vkernel h dev virtual vkernel vm vm vmspace c Written inCOperating systemDragonFly BSDTypeOS level virtualisation virtualised userspace kernelLicenceBSD LicenceWebsitevkernel 7 The virtual kernel concept is nearly the exact opposite of the unikernel concept with vkernel kernel components get to run in userspace to ease kernel development and debugging supported by a regular operating system kernel whereas with a unikernel userspace level components get to run directly in kernel space for extra performance supported by baremetal hardware or a hardware virtualisation stack However both vkernels and unikernels can be used for similar tasks as well for example to self contain software to a virtualised environment with low overhead In fact NetBSD s rump kernel originally having a focus of running kernel components in userspace has since shifted into the unikernel space as well going after the anykernel moniker for supporting both paradigms The vkernel concept is different from a FreeBSD jail in that a jail is only meant for resource isolation and cannot be used to develop and test new kernel functionality in the userland because each jail is sharing the same kernel 7 DragonFly however still has FreeBSD jail support as well 7 In DragonFly the vkernel can be thought of as a first class computer architecture comparable to i386 or amd64 and according to Matthew Dillon circa 2007 can be used as a starting point for porting DragonFly BSD to new architectures 12 DragonFly s vkernel is supported by the host kernel through new system calls that help manage virtual memory address space vmspace vmspace create et al 3 9 13 as well as extensions to several existing system calls like a href Mmap html title Mmap mmap a s madvise mcontrol 9 14 15 See also edit nbsp Free and open source software portal user mode Linux rump kernelReferences edit a b Release Notes for DragonFly 1 8 0 DragonFly BSD 2007 01 30 Retrieved 2019 04 08 a b Sascha Wildner 2007 01 08 vkernel vcd vkd vke virtual kernel architecture DragonFly Miscellaneous Information Manual DragonFly BSD vkernel vcd vkd vke virtual kernel architecture DragonFly On Line Manual Pages a b c d Matthew Dillon 2006 09 02 Cache coherency clustering and Kernel virtualization kernel Mailing list DragonFly BSD a b Jeremy C Reed ed 2007 02 10 Answers from Matt Dillon about DragonFly s virtual kernel BSD Newsletter com Reed Media net Archived from the original on 2007 02 24 Daniel Lorch 2009 06 10 Porting the HAMMER File System to Linux PDF UML runs the Linux kernel as a userspace process analogous to DragonFly BSD s virtual kernels allow for a quick recompile restart cycle and can be debugged easily with standard gdb Daniel Lorch June 10 2009 Porting the HAMMER File System to Linux PDF github Matthew Dillon 2006 sys vkernel h BSD Cross Reference DragonFly BSD a b c d David Chisnall 2007 06 15 DragonFly BSD UNIX for Clusters InformIT Prentice Hall Professional Retrieved 2019 03 06 Aggelos Economopoulos 2010 03 29 A peek at the DragonFly Virtual Kernel part 1 LWN net Retrieved 2019 04 08 a b c Aggelos Economopoulos 2010 04 16 A peek at the DragonFly Virtual Kernel part 2 LWN net Retrieved 2019 04 08 Koen Vervloesem 2010 04 21 DragonFly BSD 2 6 towards a free clustering operating system LWN net Retrieved 2019 03 07 Antti Kantee 2007 08 05 CVS commit src sys rump source changes Mailing list NetBSD Introduce RUMPs Runnable Userspace Meta Programs Jeremy Andrews 2007 08 06 Interview Matthew Dillon KernelTrap Archived from the original on 2012 02 07 Retrieved 2019 03 03 Matthew Dillon 2006 vm vm vmspace c sys vmspace create BSD Cross Reference DragonFly BSD madvise posix madvise mcontrol give advice about use of memory DragonFly System Calls Manual DragonFly BSD madvise posix madvise mcontrol give advice about use of memory DragonFly On Line Manual Pages kern syscalls master BSD Cross Reference DragonFly BSD External links editvkernel 7 man page The DragonFly virtual kernels nbsp This computing article is a stub You can help Wikipedia by expanding it vte Retrieved from https en wikipedia org w index php title Vkernel amp oldid 1117402923, wikipedia, wiki, book, books, library,
