On Jun 6, 2014, at 5:17 PM, Tim Mackey <tmac...@gmail.com> wrote: > Dave, > > I've submitted a merge review request > (https://reviews.apache.org/r/22270/) yesterday.
Unfortunately that patch did not seem to apply cleanly. I have not dug deep though.. > If you want to avoid > having to potentially deal with a bunch of conflicts, you might want > to see if your patches apply cleanly there and let me know. Happy to > help with any conflict resolution. > > btw, I didn't see a design document up on the > wiki(https://cwiki.apache.org/confluence/display/CLOUDSTACK/4.5+Design+Documents). > Can you get one there and start a DISCUSS thread? It'll probably > tease out some gotchas you might not be aware of. > > -tim > > On Fri, Jun 6, 2014 at 11:04 AM, Dave Scott <dave.sc...@citrix.com> wrote: >> Hi, >> >> Here’s a quick status update: >> >> On 16 May 2014, at 15:22, Dave Scott <dave.sc...@citrix.com> wrote: >> >>> Hi, >>> >>> On 14 May 2014, at 09:53, sebgoa <run...@gmail.com> wrote: >>> >>>> >>>> On Apr 9, 2014, at 2:37 PM, Dave Scott <dave.sc...@citrix.com> wrote: >>>> >>>>> Hi, >>>>> >>>>> Following up from Tim's "Support pure Xen as a hypervisor" proposal last >>>>> month[1] I'd like to start working on this and maybe even make a little >>>>> bit of progress while I'm at CCC in Denver. >>>>> >>>>> Helpfully James Bulpin managed to get CS + libvirt + xen to start an >>>>> instance in a simple configuration. Although the patches[2] are not >>>>> intended to be production-ready :) they help highlight some of the areas >>>>> we need to change. >>>> >>>> Dave, just to let you know that Tim has done some important "refactoring" >>>> to split up XenServer hypervisor in CS between Xen and XenServer. That way >>>> we could keep using xapi for XS but start moving to libvirt for Xen. >>>> >>>> Tim worked in the xen2server branch (don't ask about the name, I messed it >>>> up…:) ). >>>> >>>> https://git-wip-us.apache.org/repos/asf?p=cloudstack.git;a=shortlog;h=refs/heads/xen2server >>>> >>>> Would be nice to see some of the libvirt stuff in that branch to handle a >>>> new driver for Xen. >>>> >>>> Since the two hypervisors will be split up, we could still drop in some >>>> early libvirt patches to handle Xen and put this in 4.5 as a wip. >>> >>> Thanks for the links. >>> >>> I’m slowly building up a set of patches here: >>> >>> https://github.com/djs55/cloudstack/tree/virsh-capabilities >>> >>> I think once I’ve gotten to a stable-ish point I’ll rebase on top of Tim’s >>> branch. >>> >>> So far I’ve >>> * changed the hypervisor detection to use ‘virsh capabilities’ in one place >>> and ‘cat /sys/hypervisor/type’ in another. Thinking about it again, I think >>> it’s probably best to standardise on /sys/hypervisor/type since that will >>> succeed irrespective of whether the libvirtd service is chkconfig’d on or >>> not. >>> >>> * in the python cloudutils system setup stuff isKvmEnabled() has become >>> isHypervisorEnabled() >>> >>> * added a XenLibvirtDiscoverer similar to the LXC one >>> >>> * fixed what I believe is a race in sshExecuteCmdOneShotWithExitCode (which >>> seems to hit me every time, I don’t know why other people seem to be immune >>> from it): see CLOUDSTACK-6621 and review board request 21261 >>> >>> * added the new hypervisor to hypervisor.list and >>> system.vm.default.hypervisor, so it appears in the UI properly >>> >>> * registered a system VM template in the database, using the same qcow2 >>> image as KVM >>> >>> For my test host I’m using a XenServer nightly snapshot which comes with a >>> nice modern xen and kernel, and is easy to install bleeding-edge libvirt on >>> top. I had to tweak the kernel configuration and the network configuration >>> but I’m hoping to make it work out of the box in future. >>> >>> When I deploy my ‘datacenter’ the discovery phase works, the agent connects >>> and looks healthy in the logs and the UI. The next step is to figure out >>> why the system VM template isn’t being copied to primary storage — for some >>> reason the copy isn’t being attempted but I can’t see any obvious reason >>> why. >> >> I’m now at the stage of getting my system VMs to start via libvirt. The main >> missing feature is support for <channels>: low-bandwidth private >> host<->guest control channels. These channels are generally useful things >> and are needed by other projects (like oVirt), so I’d like to add them to >> libxl and libvirt’s libxl driver. There’s a thread on xen-devel and >> libvir-devel if anyone’s interested: >> >> http://www.redhat.com/archives/libvir-list/2014-June/msg00180.html >> >> Once the <channels> are sorted, basic VM operations should work. The next >> step would be to rebase my patches on top of Tim’s renaming changes and tidy >> them up for review. >> >> Cheers, >> Dave >> >>> >>> Cheers, >>> Dave >>> >>>> >>>> -Sebastien >>>> >>>>> >>>>> Some of the areas are: >>>>> >>>>> 1. hypervisor detection >>>>> >>>>> Where we currently look for KVM specifically ("lsmod | grep kvm") we >>>>> could switch to either detecting any Linux hypervisor (by reading >>>>> /sys/hypervisor/type) and assuming if a hypervisor is present then we can >>>>> use libvirt on it (is this a fair assumption?) Or we could white-list >>>>> “kvm” or “xen”. Or we could query libvirt directly (perhaps via 'virsh >>>>> capabilities'?) >>>>> >>>>> 2. fiddling with the domain.xml >>>>> >>>>> When starting a domain via libvirt the XML configuration has >>>>> hypervisor-specific stuff in it. Some of this is easy to change like: >>>>> >>>>> <domain type='kvm'> >>>>> >>>>> obviously becomes >>>>> >>>>> <domain type='xen'> >>>>> >>>>> and >>>>> >>>>> <emulator>/usr/libexec/qemu-kvm</emulator> >>>>> >>>>> should probably be >>>>> >>>>> <emulator>/some/other/path/qemu-dm</emulator> >>>>> >>>>> Some is a bit more invasive (to the VM) such as the virtual hardware type >>>>> should be switched from "virtio" to "xen" (and the block device in Linux >>>>> will change from /dev/vd* to /dev/xvd*) and we'll have to either >>>>> implement or work around the lack of >>>>> >>>>> <channel type='unix'> ... >>>>> >>>>> -- I presume this is a control channel into the system VM. Perhaps we >>>>> could implement this in libvirt/libxl using vchan? >>>>> >>>>> 3. system VMs? >>>>> >>>>> It would be very convenient if the system VM images could work on both >>>>> xen and KVM. This is probably doable as long as we don't bake in virtual >>>>> hardware specific information (such as /dev/vda) in the image. We could >>>>> use the qcow2 format in both cases. What do you think? >>>>> >>>>> … and I’m sure there’s more. >>>>> >>>>> Anyway, feedback would be welcome. If anyone else in Denver wants to >>>>> chat, then come grab me later! >>>>> >>>>> Cheers, >>>>> Dave Scott >>>>> >>>>> [1] >>>>> http://mail-archives.apache.org/mod_mbox/cloudstack-users/201403.mbox/%3ccajgxtbnbmqtq81ralgh2kma7v5wjyzkr3xnyasmkc_br+uk...@mail.gmail.com%3e >>>>> >>>>> [2] >>>>> https://github.com/jamesbulpin/cloudstack/commits/jamesb_xen_exploratory >>
