[Kimchi-devel] [PATCH][Kimchi 1/2] Issue #838: Extend memory hotplug feature test

[Aline Manera]

On 03/22/2016 11:18 AM, Rodrigo Trujillo wrote:
> If QEMU version is < 2.1, qemu is not going to start guest which have
> maxmemory tag configured in the XML. Kimchi adds this tag by default in
> order to allow memory hotplug.
> In other words, in order to allow memory hotplug, versions must be
> libvirt >= 1.2.14 and qemu >= 2.1. Libvirt was already being tested by
> the feature test, but qemu did not. Distros as Red Hat 7 and CentOS
> still are in qemu 1.5.
> This patch extend the feature test and do not create maxmemory tag in
> order to avoid problems in those distros.
>
> Signed-off-by: Rodrigo Trujillo <rodrigo.trujillo at linux.vnet.ibm.com>
> ---
>   i18n.py               |  2 +-
>   model/featuretests.py | 20 +++++++++++++-------
>   model/vms.py          |  8 ++++++++
>   vmtemplate.py         |  7 ++++++-
>   4 files changed, 28 insertions(+), 9 deletions(-)
>
> diff --git a/i18n.py b/i18n.py
> index beefeb5..6214687 100644
> --- a/i18n.py
> +++ b/i18n.py
> @@ -99,7 +99,7 @@ messages = {
>       "KCHVM0043E": _("Only increase memory is allowed in active VMs"),
>       "KCHVM0044E": _("For live memory update, new memory value must be equal old memory value plus multiples of 1024 Mib"),
>       "KCHVM0045E": _("There are not enough free slots of 1024 Mib in the guest."),
> -    "KCHVM0046E": _("Host's libvirt version does not support memory devices. Libvirt must be >= 1.2.14"),
> +    "KCHVM0046E": _("Host's libvirt or qemu version does not support memory devices and memory hotplug. Libvirt must be >= 1.2.14 and QEMU must be >= 2.1."),
>       "KCHVM0047E": _("Error attaching memory device. Details: %(error)s"),
>       "KCHVM0048E": _("Cannot start %(name)s. Virtual machine is already running."),
>       "KCHVM0049E": _("Cannot power off %(name)s. Virtual machine is shut off."),
> diff --git a/model/featuretests.py b/model/featuretests.py
> index 378335a..ba728e1 100644
> --- a/model/featuretests.py
> +++ b/model/featuretests.py
> @@ -72,6 +72,14 @@ MAXMEM_VM_XML = """
>       <type arch='%(arch)s'>hvm</type>
>       <boot dev='hd'/>
>     </os>

> +  <cpu>
> +    <numa>
> +      <cell id='0' cpus='0' memory='10240' unit='KiB'/>
> +    </numa>
> +  </cpu>
> +  <features>
> +    <acpi/>
> +  </features>

Is it really needed?

>   </domain>"""
>
>   DEV_MEM_XML = """
> @@ -209,13 +217,9 @@ class FeatureTests(object):
>           A memory device can be hot-plugged or hot-unplugged since libvirt
>           version 1.2.14.
>           '''
> -        # Libvirt < 1.2.14 does not support memory devices, so firstly, check
> -        # its version, then try to attach a device. These steps avoid errors
> -        # with Libvirt 'test' driver for KVM
> -        version = 1000000*1 + 1000*2 + 14
> -        if libvirt.getVersion() < version:
> -            return False
> -
> +        # Libvirt < 1.2.14 does not support memory devices, so try to attach a
> +        # device. Then check if QEMU (>= 2.1) supports memory hotplug, starting
> +        # the guest These steps avoid errors with Libvirt 'test' driver for KVM
>           with RollbackContext() as rollback:
>               FeatureTests.disable_libvirt_error_logging()
>               rollback.prependDefer(FeatureTests.enable_libvirt_error_logging)
> @@ -230,6 +234,8 @@ class FeatureTests(object):
>               try:
>                   dom.attachDeviceFlags(DEV_MEM_XML,
>                                         libvirt.VIR_DOMAIN_MEM_CONFIG)
> +                dom.create()
> +                rollback.prependDefer(dom.destroy)
>                   return True
>               except libvirt.libvirtError:
>                   return False
> diff --git a/model/vms.py b/model/vms.py
> index 03ffdae..557d37a 100644
> --- a/model/vms.py
> +++ b/model/vms.py
> @@ -809,6 +809,14 @@ class VMModel(object):
>           return (nonascii_name if nonascii_name is not None else vm_name, dom)
>
>       def _update_memory_config(self, xml, params):
> +        # Cannot pass max memory if there is not support to memory hotplug
> +        # Then set max memory as memory, just to continue with the update
> +        if not self.caps.mem_hotplug_support:
> +            if 'maxmemory' in params['memory']:
> +                raise InvalidOperation("KCHVM0046E")
> +            else:
> +                params['memory']['maxmemory'] = params['memory']['current']
> +
>           root = ET.fromstring(xml)
>           # MiB to KiB
>           hasMem = 'current' in params['memory']
> diff --git a/vmtemplate.py b/vmtemplate.py
> index 4bcf324..535efd7 100644
> --- a/vmtemplate.py
> +++ b/vmtemplate.py
> @@ -32,6 +32,7 @@ from wok.exception import MissingParameter, OperationFailed
>   from wok.plugins.kimchi import imageinfo
>   from wok.plugins.kimchi import osinfo
>   from wok.plugins.kimchi.isoinfo import IsoImage
> +from wok.plugins.kimchi.model.config import CapabilitiesModel
>   from wok.plugins.kimchi.utils import check_url_path, pool_name_from_uri
>   from wok.plugins.kimchi.xmlutils.cpu import get_cpu_xml
>   from wok.plugins.kimchi.xmlutils.disk import get_disk_xml
> @@ -118,6 +119,8 @@ class VMTemplate(object):
>               disk_info['index'] = disk_info.get('index', index)
>               self.info['disks'][index] = disk_info

> +        self.caps = CapabilitiesModel()
> +

VMTemplate must be independent of Model. In fact, you don't know which 
Model instance is being using.
So you should pass the information from Model to VMTemplate as parameter.

Use kwargs argument from to_vm_xml() function.

def to_vm_xml(self, vm_name, vm_uuid, **kwargs):

>       def _get_os_info(self, args, scan):
>           distro = version = 'unknown'
>
> @@ -376,7 +379,9 @@ class VMTemplate(object):
>           # Rearrange memory parameters
>           params['memory'] = self.info['memory'].get('current')
>           params['max_memory'] = ""
> -        if memory != maxmemory:
> +        # if there is not support to memory hotplug in Libvirt or qemu, we
> +        # cannot add the tag maxMemory
> +        if memory != maxmemory and self.caps.mem_hotplug_support:
>               maxmem_xml = "<maxMemory slots='%s' unit='MiB'>%s</maxMemory>"
>               params['max_memory'] = maxmem_xml % (slots, maxmemory)
>