[virt-tools-list] [virt-manager PATCH 1/2] domain: add support to rename domain with nvram vars file

[Cole Robinson]

On 03/06/2017 03:43 AM, Pavel Hrdina wrote:
> Libvirt storage API doesn't support renaming storage volumes so
> we need to copy the nvram file and remove the old one.
> 
> Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1368922
> 
> Signed-off-by: Pavel Hrdina <phrdina at redhat.com>
> ---
>  virtManager/details.py |  3 ++-
>  virtManager/domain.py  | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 48 insertions(+), 2 deletions(-)
> 
> diff --git a/virtManager/details.py b/virtManager/details.py
> index d6fef967..0b2754d8 100644
> --- a/virtManager/details.py
> +++ b/virtManager/details.py
> @@ -1975,7 +1975,8 @@ class vmmDetails(vmmGObjectUI):
>          # This needs to be last
>          if self.edited(EDIT_NAME):
>              # Renaming is pretty convoluted, so do it here synchronously
> -            self.vm.define_name(self.widget("overview-name").get_text())
> +            self.vm.rename_domain(self.widget("overview-name").get_text(),
> +                                  kwargs)
>  
>              if not kwargs and not hotplug_args:
>                  # Saves some useless redefine attempts
> diff --git a/virtManager/domain.py b/virtManager/domain.py
> index 336584e5..79303890 100644
> --- a/virtManager/domain.py
> +++ b/virtManager/domain.py
> @@ -32,6 +32,7 @@ from virtinst import DomainSnapshot
>  from virtinst import Guest
>  from virtinst import util
>  from virtinst import VirtualController
> +from virtinst import VirtualDisk
>  
>  from .libvirtobject import vmmLibvirtObject
>  
> @@ -557,6 +558,42 @@ class vmmDomain(vmmLibvirtObject):
>      # Persistent XML change APIs #
>      ##############################
>  
> +    def rename_domain(self, new_name, kwargs):
> +        old_name = self.get_name()
> +
> +        self.define_name(new_name)
> +
> +        # We need to do this copy magic because there is no Libvirt storage API
> +        # to rename storage volume.
> +        try:
> +            old_nvram = VirtualDisk(self.conn.get_backend())
> +            old_nvram.path = self.get_xmlobj().os.nvram
> +
> +            nvram_dir = os.path.dirname(old_nvram.path)
> +            new_nvram_path = os.path.join(nvram_dir, "%s_VARS.fd" % new_name)
> +
> +            new_nvram = VirtualDisk(self.conn.get_backend())
> +            new_nvram.path = new_nvram_path
> +
> +            nvram_install = VirtualDisk.build_vol_install(
> +                    self.conn.get_backend(), os.path.basename(new_nvram.path),
> +                    new_nvram.get_parent_pool(), new_nvram.get_size(), False)
> +            nvram_install.input_vol = old_nvram.get_vol_object()
> +            nvram_install.sync_input_vol(only_format=True)
> +
> +            new_nvram.set_vol_install(nvram_install)
> +            new_nvram.validate()
> +            new_nvram.setup()
> +        except Exception as e:
> +            self.define_name(old_name)
> +            raise RuntimeError("Cannot rename nvram VARS: '%s'" % e)

This breaks when the VM doesn't have any nvram. virt-manager --connect
test:///default  and try renaming the 'test' VM.

Please break all the nvram copying out into a separate function, for code clarity

I think the ordering here should be:
* If the VM has NVRAM, try to copy it. If it fails, exit.
* Rename the VM. If it fails, try to delete the new NVRAM file, but don't
overwrite the error
* Delete the original NVRAM file. If it fails, raise the error but don't try
to rollback the rename

> +
> +        kwargs["nvram"] = new_nvram_path
> +        try:
> +            old_nvram.get_vol_object().delete(0)
> +        except Exception as e:
> +            logging.debug("old nvram file was not removed: '%s'", e)
> +
>      # Device Add/Remove
>      def add_device(self, devobj):
>          """
> @@ -621,7 +658,8 @@ class vmmDomain(vmmLibvirtObject):
>          self._redefine_xmlobj(guest)
>  
>      def define_overview(self, machine=_SENTINEL, description=_SENTINEL,
> -        title=_SENTINEL, idmap_list=_SENTINEL, loader=_SENTINEL):
> +        title=_SENTINEL, idmap_list=_SENTINEL, loader=_SENTINEL,
> +        nvram=_SENTINEL):
>          guest = self._make_xmlobj_to_define()
>          if machine != _SENTINEL:
>              guest.os.machine = machine
> @@ -644,6 +682,9 @@ class vmmDomain(vmmLibvirtObject):
>                  guest.os.loader_type = "pflash"
>                  guest.os.loader_ro = True
>  
> +        if nvram != _SENTINEL and guest.os.loader is not None:
> +            guest.os.nvram = nvram
> +
>          if idmap_list != _SENTINEL:
>              if idmap_list is not None:
>                  # pylint: disable=unpacking-non-sequence
> @@ -1434,6 +1475,10 @@ class vmmDomain(vmmLibvirtObject):
>              if (self.get_xmlobj().os.loader_ro is True and
>                  self.get_xmlobj().os.loader_type == "pflash"):
>                  flags |= getattr(libvirt, "VIR_DOMAIN_UNDEFINE_NVRAM", 0)
> +        else:
> +            if (self.get_xmlobj().os.loader_ro is True and
> +                self.get_xmlobj().os.loader_type == "pflash"):
> +                flags |= getattr(libvirt, "VIR_DOMAIN_UNDEFINE_KEEP_NVRAM", 0)

Can you break out the duplicate loader check into a variable has_nvram or similar

Also can you add a comment here that the force=False path is used when
renaming the VM, and KEEP_NVRAM is required for that case. It wasn't obvious to me

Thanks,
Cole