Open Stack

Hi!

I believe that your're facing the very same problem I encountered... Like this:

http://askubuntu.com/questions/492830/how-to-integrate-libvirt-with-libxl-of-xen-4-4

Long story short, it doesn't work anymore (i.e., libvirt + xen 4.4
with xl - on Trusty)...    :-/

Nevertheless, when with `KVM`, you can have much more instances per
Compute Node, because of `KSM` (Kernel Same Page Merging). For
example, in a compute node with 48G of RAM, `KSM` save-me about
22~28G...

Maybe when with `Xen`, you can tell Nova to make use of Xen's "memory
/ maxmem" options in a very efficient manner... But I'm not sure if it
is currently possible.

The good when with `KVM+KSM` (Ubuntu metapackage
`ubuntu-virt-server`), is that you just need to rise up your Nova's
`ram_allocation_ratio` make make more use of it, simple and efficient.

Someone please, correct-me if I'm wrong...    :-)

Best!
Thiago

On 5 November 2014 19:37, Xing Lin <linxingnku at gmail.com> wrote:
> Hi,
>
> I am aware that Xen via libvirt is in the group C support but since I am not
> able to install xenserver iso at compute machines I have, I have to consider
> to use xen with libvirt. I have three nodes, each one running ubuntu 14.04.
> I follow the instruction to install juno in ubuntu 14.04 and it works (I can
> create instances from horizon) when I use kvm as the hypervisor at the
> compute node . However, if I switch to use xen as the hypervisor, it will
> fail to create instances. Note that I am able to create a xen guest with
> virt-install from command line, with the following command. So, I believe I
> am quite close to get libvirt + xl work for openstack. Any help will be
> highly appreciated! Thanks,
>
> "$ virt-install --connect=xen:/// --name u14.04.3 --ram 1024 --disk
> u14.04.3.img,size=4 --location
> http://ftp.ubuntu.com/ubuntu/dists/trusty/main/installer-amd64/ --network
> bridge=virbr0"
>
> libxl log when creating an instance, launched from horizon (failed).
> ------------------
> libxl: debug: libxl_create.c:1342:do_domain_create: ao 0x7f4e5c001890:
> create: how=(nil) callback=(nil) poller=0x7f4e5c000c50
> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: Disk
> vdev=sda spec.backend=qdisk
> libxl: debug: libxl_create.c:797:initiate_domain_create: running bootloader
> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: Disk
> vdev=(null) spec.backend=qdisk
> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: Disk
> vdev=xvda spec.backend=qdisk
> libxl: debug: libxl_event.c:618:libxl__ev_xswatch_deregister: watch
> w=0x7f4e5c001e20: deregister unregistered
> libxl: debug: libxl.c:2712:local_device_attach_cb: locally attaching qdisk
> /dev/xvda
> libxl: error: libxl_device.c:1224:libxl__wait_for_backend: Backend
> /local/domain/0/backend/qdisk/0/51712 not ready
> libxl: error: libxl_bootloader.c:405:bootloader_disk_attached_cb: failed to
> attach local disk for bootloader execution
> libxl: debug: libxl_event.c:618:libxl__ev_xswatch_deregister: watch
> w=0x7f4e5c001f48: deregister unregistered
> libxl: error: libxl_bootloader.c:276:bootloader_local_detached_cb: unable to
> detach locally attached disk
> libxl: error: libxl_create.c:1022:domcreate_rebuild_done: cannot (re-)build
> domain: -3
> libxl: debug: libxl_event.c:1591:libxl__ao_complete: ao 0x7f4e5c001890:
> complete, rc=-3
> libxl: debug: libxl_create.c:1356:do_domain_create: ao 0x7f4e5c001890:
> inprogress: poller=0x7f4e5c000c50, flags=ic
> libxl: debug: libxl_event.c:1563:libxl__ao__destroy: ao 0x7f4e5c001890:
> destroy
> xc: debug: hypercall buffer: total allocations:24 total releases:24
> xc: debug: hypercall buffer: current allocations:0 maximum allocations:2
> xc: debug: hypercall buffer: cache current size:2
> xc: debug: hypercall buffer: cache hits:20 misses:2 toobig:2
> libxl: debug: libxl_create.c:1342:do_domain_create: ao 0x7f4e540083e0:
> create: how=(nil) callback=(nil) poller=0x7f4e54007fb0
> ....
> --------------------
>
>
> libxl log when creating an instance with virt-install from command line
> (succeed).
> --------------------
> libxl: debug: libxl_create.c:1342:do_domain_create: ao 0x7f4e641b3ba0:
> create: how=(nil) callback=(nil) poller=0x7f4e640a94d0
> libxl: debug: libxl_device.c:251:libxl__device_disk_set_backend: Disk
> vdev=xvda spec.backend=unknown
> libxl: debug: libxl_device.c:197:disk_try_backend: Disk vdev=xvda, backend
> phy unsuitable as phys path not a block device
> libxl: debug: libxl_device.c:286:libxl__device_disk_set_backend: Disk
> vdev=xvda, using backend qdisk
> libxl: debug: libxl_create.c:797:initiate_domain_create: running bootloader
> libxl: debug: libxl_bootloader.c:327:libxl__bootloader_run: no bootloader
> configured, using user supplied kernel
> libxl: debug: libxl_event.c:618:libxl__ev_xswatch_deregister: watch
> w=0x7f4e641cd2f8: deregister unregistered
> libxl: debug: libxl_numa.c:475:libxl__get_numa_candidate: New best NUMA
> placement candidate found: nr_nodes=1, nr_cpus=8, nr_vcpus=9,
> free_memkb=1293
> libxl: detail: libxl_dom.c:195:numa_place_domain: NUMA placement candidate
> with 1 nodes, 8 cpus and 1293 KB free selected
> domainbuilder: detail: xc_dom_allocate:
> cmdline="method=http://ftp.ubuntu.com/ubuntu/dists/trusty/main/installer-amd64/",
> features="(null)"
> libxl: debug: libxl_dom.c:357:libxl__build_pv: pv kernel mapped 0 path
> /var/lib/xen/virtinst-vmlinuz.mBNvPH
> domainbuilder: detail: xc_dom_kernel_file:
> filename="/var/lib/xen/virtinst-vmlinuz.mBNvPH"
> domainbuilder: detail: xc_dom_malloc_filemap    : 5643 kB
> domainbuilder: detail: xc_dom_ramdisk_file:
> filename="/var/lib/xen/virtinst-initrd.gz.Br5nZP"
> domainbuilder: detail: xc_dom_malloc_filemap    : 20758 kB
> domainbuilder: detail: xc_dom_boot_xen_init: ver 4.4, caps xen-3.0-x86_64
> xen-3.0-x86_32p hvm-3.0-x86_32 hvm-3.0-x86_32p hvm-3.0-x86_64
> domainbuilder: detail: xc_dom_parse_image: called
> domainbuilder: detail: xc_dom_find_loader: trying multiboot-binary loader
> ...
> domainbuilder: detail: loader probe failed
> domainbuilder: detail: xc_dom_find_loader: trying Linux bzImage loader ...
> domainbuilder: detail: xc_dom_malloc            : 18898 kB
> domainbuilder: detail: xc_dom_do_gunzip: unzip ok, 0x5761bf -> 0x12749b8
> domainbuilder: detail: loader probe OK
> ...
> ------------------
>
> -Xing
>
>
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