ubuntu下kvm 命令行安装64位ubuntu报"Couldn't find hvm kernel for Ubuntu tree."的问题分析

1.安装ubuntu时使用的virt-install的配置：

virt-install \
--name test4 \
--ram 1024 \
--disk path=/data/01_ubuntu/ubuntu4.img,size=6 \
--vcpus 1 \
--hvm \
--os-type linux \
--network network=default \
--os-variant ubuntuquantal \
--graphics none \
--console pty,target_type=serial \
--location /data/00_osfile/ubuntu-16.04.1-server-amd64.iso \
--extra-args 'console=ttyS0,115200n8 serial'

报错如下：

ERROR Couldn't find hvm kernel for Ubuntu tree.
Domain installation does not appear to have been successful.

通过查资料发现，virt-install可以开debug模式的，加入--debug选项即可

2.virt-install的debug模式得到的结果：

[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:268) local hasFile: Couldn't find /var/lib/libvirt/boot/virtinstmnt.xPL9y1/current/images/MANIFEST
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:89) Fetching URI: /var/lib/libvirt/boot/virtinstmnt.xPL9y1/install/netboot/version.info
Retrieving file version.info... | 58 B 00:00:00
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:1164) Didn't find any known codename in the URL string
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:511) Detected distro name=Ubuntu osvariant=linux
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:268) local hasFile: Couldn't find /var/lib/libvirt/boot/virtinstmnt.xPL9y1/install/netboot/ubuntu-installer/i386/linux

这里就可以看出问题了，明明是64位的操作系统，为什么去找./install/netboot/ubuntu-install/i386/linux的路径

我们去看看iso文件中正确的路径是什么：

[root@11.102 01_ubuntu]$mount /data/00_osfile/ubuntu-16.04.1-server-amd64.iso /mnt
mount: /dev/loop2 is write-protected, mounting read-only
[root@11.102 01_ubuntu]$ls /mnt/install/netboot/ubuntu-installer/amd64/linux
/mnt/install/netboot/ubuntu-installer/amd64/linux

基本确定，如果将路径的i386改为amd64，virt-install安装就没有问题。

debug模式剩余的log：

[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (urlfetcher:320) Cleaning up mount at /var/lib/libvirt/boot/virtinstmnt.xPL9y1
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (cli:305) File "/usr/share/virt-manager/virt-install", line 1077, in <module>
sys.exit(main())
File "/usr/share/virt-manager/virt-install", line 1071, in main
start_install(guest, continue_inst, options)
File "/usr/share/virt-manager/virt-install", line 775, in start_install
fail(e, do_exit=False)
File "/usr/share/virt-manager/virtinst/cli.py", line 305, in fail
logging.debug("".join(traceback.format_stack()))
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] ERROR (cli:306) Couldn't find hvm kernel for Ubuntu tree.
[Wed, 30 Nov 2016 11:16:07 virt-install 26900] DEBUG (cli:308)
Traceback (most recent call last):
File "/usr/share/virt-manager/virt-install", line 747, in start_install
dom = guest.start_install(meter=meter, noboot=options.noreboot)
File "/usr/share/virt-manager/virtinst/guest.py", line 491, in start_install
self._prepare_install(meter, dry)
File "/usr/share/virt-manager/virtinst/guest.py", line 304, in _prepare_install
self.installer.prepare(self, meter)
File "/usr/share/virt-manager/virtinst/installer.py", line 200, in prepare
self._prepare(guest, meter)
File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 451, in _prepare
self._prepare_kernel_url(guest, fetcher)
File "/usr/share/virt-manager/virtinst/distroinstaller.py", line 360, in _prepare_kernel_url
kernel, initrd, args = store.acquireKernel(guest)
File "/usr/share/virt-manager/virtinst/urlfetcher.py", line 603, in acquireKernel
{"distro": self.name, "type" : self.type})
RuntimeError: Couldn't find hvm kernel for Ubuntu tree.

3.修改virt-manager代码：

通过上面的报错，发现virt-manager使用python写的！正好想看什么源码来自，这个正好！

通过对virt-manager这一项目一步步debug，找到问题：

[root@11.102 ~]$grep -n -A22 "class DebianDistro" /usr/share/virt-manager/virtinst/urlfetcher.py
1076:class DebianDistro(Distro):
1077- # ex. http://ftp.egr.msu.edu/debian/dists/sarge/main/installer-i386/
1078- # daily builds: http://d-i.debian.org/daily-images/amd64/
1079- name = "Debian"
1080- urldistro = "debian"
1081- os_variant = "linux"
1082-
1083- def __init__(self, *args, **kwargs):
1084- Distro.__init__(self, *args, **kwargs)
1085-
1086- # Pull the tree's arch out of the URL text
1087- self._treeArch = 'i386'
1088- for pattern in ["^.*/installer-(\w+)/?$",
1089- "^.*/daily-images/(\w+)/?$"]:
1090- arch = re.findall(pattern, self.uri)
1091- if arch:
1092- self._treeArch = arch[0]
1093- break
1094-
1095- self._url_prefix = 'current/images'
1096- self._installer_dirname = self.name.lower() + "-installer"
1097- self._set_media_paths()

发现基于Debian的系统，__init__方法中self._treeArch初始化时是i386，估计是virt-manager读取ubuntu的iso文件时，出了什么问题，没读出该系统是x86_64类型，将该值改为amd64,就可以了。

再次运行virt-install，成功进入ubuntu安装界面！

附：CentOS命令行使用KVM安装64位ubuntu报"Couldn't find hvm kernel for Ubuntu tree."的解决办法

grep -n -A21 'class DebianDistro' /usr/lib/python2.6/site-packages/virtinst/OSDistro.py 命令可以查看DebianDistro类的__init__方法

[root@2 virtinst]$grep -n -A21 'class DebianDistro' /usr/lib/python2.6/site-packages/virtinst/OSDistro.py
892:class DebianDistro(Distro):
893- # ex. http://ftp.egr.msu.edu/debian/dists/sarge/main/installer-i386/
894- # daily builds: http://people.debian.org/~joeyh/d-i/
895-
896- name = "Debian"
897- os_type = "linux"
898-
899- def __init__(self, uri, arch, vmtype=None, scratchdir=None):
900- Distro.__init__(self, uri, arch, vmtype, scratchdir)
901- if uri.count("installer-i386"):
902- self._treeArch = "i386"
903- elif uri.count("installer-amd64"):
904- self._treeArch = "amd64"
905- else:
906- self._treeArch = "i386"
907-
908- if re.match(r'i[4-9]86', arch):
909- self.arch = 'i386'
910-
911- self._installer_name = self.name.lower() + "-" + "installer"
912- self._prefix = 'current/images'
913- self._set_media_paths()

改变__init__方法里的else：条件下面的一行，将"i386"改为"amd64"即可

- self._treeArch = 'i386'
+ self._treeArch = 'amd64'