virt-install: Add --os-variant 'none' option to disable autodetect

First, add a new method set_os_detect to Guest, so that API users can opt
into the behavior, and set the behavior off by default.

However, virt-install will continue to do autodetect by default, but now
users have a way to opt out via --os-variant none

Author: crobinso

man/en/virt-install.pod.in

@@ -123,13 +123,25 @@ an optimal cpu pinning using NUMA data, if available.
 Optimize the guest configuration for a type of operating system (ex. 'linux',
 'windows'). This will attempt to pick the most suitable ACPI & APIC settings,
 optimally supported mouse drivers, virtio, and generally accommodate other
-operating system quirks. See C<--os-variant> for valid options.
+operating system quirks.
+
+By default, virt-install will attempt to auto detect this value from
+the install media (currently only supported for URL installs). Autodetection
+can be disabled with the special value 'none'
+
+See C<--os-variant> for valid options.
 
 =item --os-variant=OS_VARIANT
 
 Further optimize the guest configuration for a specific operating system
 variant (ex. 'fedora8', 'winxp'). This parameter is optional, and does not
-require an C<--os-type> to be specified. Valid values are:
+require an C<--os-type> to be specified.
+
+By default, virt-install will attempt to auto detect this value from
+the install media (currently only supported for URL installs). Autodetection
+can be disabled with the special value 'none'.
+
+Valid values are:
 
 ::VARIANT VALUES::
 

setup.py

@@ -235,6 +235,10 @@ def _update_manpages(self):
                 output += osdict.OS_TYPES[t]["variants"][v]["label"] + "\n\n"
 
             output += "=back\n\n"
+
+        # Add special 'none' value
+        output += "=item none\n\n"
+        output += "No OS version specified (disables autodetect)\n\n"
         output += "=back\n\n"
 
         infile = "man/en/virt-install.pod.in"

tests/clitest.py

@@ -202,6 +202,10 @@
         "--paravirt --location %s" % treedir,
         # Using ro path as a cd media
         "--hvm --cdrom %(ROIMG)s",
+        # Paravirt location with --os-variant none
+        "--paravirt --location %s --os-variant none" % treedir,
+        # URL install with manual os-variant
+        "--hvm --location %s --os-variant fedora12" % treedir,
       ],
 
       "invalid": [
@@ -215,6 +219,8 @@
         "--import",
         # LiveCD with no media
         "--livecd",
+        # Bogus --os-variant
+        "--hvm --pxe --os-variant farrrrrrrge"
       ],
      }, # category "install"
 
@@ -487,6 +493,8 @@
         "--boot 1",
         # Lots of options
         "--name foobar --ram 64 --os-variant winxp",
+        # OS variant 'none'
+        "--name foobar --ram 64 --os-variant none",
       ],
 
       "invalid": [

virt-image

@@ -214,10 +214,7 @@ def main():
     get_graphics(image.domain, options.vnc, options.vncport, options.vnclisten,
                  options.nographics, options.sdl, options.keymap, guest)
 
-    if options.distro_type:
-        guest.set_os_type(options.distro_type)
-    if options.distro_variant:
-        guest.set_os_variant(options.distro_variant)
+    cli.set_os_variant(guest, options.distro_type, options.distro_variant)
 
     if installer.is_hvm():
         if options.noacpi:

virt-install

@@ -772,10 +772,7 @@ def main():
     cli.get_hostdevs(options.hostdevs, guest)
 
     guest.extraargs = options.extra
-    if options.distro_type:
-        guest.set_os_type(options.distro_type)
-    if options.distro_variant:
-        guest.set_os_variant(options.distro_variant)
+    cli.set_os_variant(guest, options.distro_type, options.distro_variant)
 
     # and now for the full-virt vs paravirt specific questions
     get_install_media(options.location, options.cdrom, options.pxe,

virtinst/DistroInstaller.py

@@ -193,15 +193,15 @@ def _prepare_kernel_and_initrd(self, guest, distro, meter):
                 self.location, meter, guest.arch, scratchdir=self.scratchdir,
                 type=self.os_type, distro=distro)
 
-            # Only set OS type if the user didn't explictly pass one
-            # XXX: Should this be opt in?
-            if guest.os_type == None and os_type:
-                logging.debug("Auto detected OS type as: %s" % os_type)
-                guest.os_type = os_type
-            if (guest.os_variant == None and os_variant
-                and guest.os_type == os_type):
-                logging.debug("Auto detected OS variant as: %s" % os_variant)
-                guest.os_variant = os_variant
+            if guest.get_os_autodetect():
+                if os_type:
+                    logging.debug("Auto detected OS type as: %s" % os_type)
+                    guest.os_type = os_type
+
+                if (os_variant and guest.os_type == os_type):
+                    logging.debug("Auto detected OS variant as: %s" %
+                                  os_variant)
+                    guest.os_variant = os_variant
 
             self.install["kernel"] = kernelfn
             self.install["initrd"] = initrdfn

virtinst/Guest.py

@@ -120,6 +120,7 @@ def __init__(self, type=None, connection=None, hypervisorURI=None,
         self._cpuset = None
         self._graphics_dev = None
         self._consolechild = None
+        self._os_autodetect = False
 
         self._os_type = None
         self._os_variant = None
@@ -291,6 +292,12 @@ def set_os_variant(self, val):
             raise ValueError, _("Unknown OS variant '%s'" % val)
     os_variant = property(get_os_variant, set_os_variant)
 
+    def set_os_autodetect(self, val):
+        self._os_autodetect = bool(val)
+    def get_os_autodetect(self):
+        return self._os_autodetect
+    os_autodetect = property(get_os_autodetect, set_os_autodetect)
+
     # Get the current variants 'distro' tag: 'rhel', 'fedora', etc.
     def get_os_distro(self):
         return self._lookup_osdict_key("distro")

virtinst/cli.py

@@ -548,6 +548,17 @@ def get_network(net_kwargs, guest):
     n = VirtualNetworkInterface(**net_kwargs)
     guest.nics.append(n)
 
+def set_os_variant(guest, distro_type, distro_variant):
+    if not distro_type and not distro_variant:
+        # Default to distro autodetection
+        guest.set_os_autodetect(True)
+    else:
+        if (distro_type and str(distro_type).lower() != "none"):
+            guest.set_os_type(distro_type)
+
+        if (distro_variant and str(distro_variant).lower() != "none"):
+            guest.set_os_variant(distro_variant)
+
 
 def parse_optstr(optstr, basedict=None):
     """