我在CentOS 6 x64系统上使用yum从内核2.6.32-220更新到2.6.32-200.23.1。 我现在在启动时在控制台上收到以下消息：
mknod: '/dev/null' : File exists mknod: '/dev/console: File exists /init: 102: cannot open /proc/cmdline: No such file mkdir: cannot create directory '/dev/pts': File exists dracut: FATAL: No or empty root= argument dracut: Refusing to continue Kernel panic - not syncing: Attempted to kill init! 在启动时select较旧的内核版本允许我正常启动。 这个问题在我尝试升级的所有四个虚拟机上都是可重现的。 他们都是同一台CentOS 6.2 x64主机上的CentOS 6.2 x64 guest。 每个虚拟机的文件系统位于iSCSI SAN卷上。 这是VM的/etc/grub.conf文件：
default=0 timeout=5 splashimage=(hd0,0)/grub/splash.xpm.gz hiddenmenu title CentOS (2.6.32-220.23.1.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-220.23.1.el6.x86_64 ro root=/dev/mapper/vg_main-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_main/lv_swap rd_NO_MD quiet SYSFONT=latarcyrhe b-sun16 rhgb crashkernel=auto rd_LVM_LV=vg_main/lv_root rhgb crashkernel=auto quiet KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM initrd /initramfs-2.6.32-220.23.1.el6.x86_64.img title CentOS (2.6.32-220.7.1.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-220.7.1.el6.x86_64 ro root=/dev/mapper/vg_main-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_main/lv_swap rd_NO_MD quiet SYSFONT=latarcyrheb -sun16 rhgb crashkernel=auto rd_LVM_LV=vg_main/lv_root rhgb crashkernel=auto quiet KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM initrd /initramfs-2.6.32-220.7.1.el6.x86_64.img title CentOS (2.6.32-220.4.2.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-220.4.2.el6.x86_64 ro root=/dev/mapper/vg_main-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_main/lv_swap rd_NO_MD quiet SYSFONT=latarcyrheb -sun16 rhgb crashkernel=auto rd_LVM_LV=vg_main/lv_root rhgb crashkernel=auto quiet KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM initrd /initramfs-2.6.32-220.4.2.el6.x86_64.img title CentOS (2.6.32-220.el6.x86_64) root (hd0,0) kernel /vmlinuz-2.6.32-220.el6.x86_64 ro root=/dev/mapper/vg_main-lv_root rd_NO_LUKS LANG=en_US.UTF-8 rd_LVM_LV=vg_main/lv_swap rd_NO_MD quiet SYSFONT=latarcyrheb-sun 16 rhgb crashkernel=auto rd_LVM_LV=vg_main/lv_root rhgb crashkernel=auto quiet KEYBOARDTYPE=pc KEYTABLE=us rd_NO_DM initrd /initramfs-2.6.32-220.el6.x86_64.img
这里是主机上的VMconfiguration文件：
<domain type='kvm' id='117'> <name>test1</name> <uuid>6b783832-bb85-6a8e-2dad-5898d3c87259</uuid> <memory>1048576</memory> <currentMemory>1048576</currentMemory> <vcpu>1</vcpu> <os> <type arch='x86_64' machine='rhel6.2.0'>hvm</type> <boot dev='hd'/> </os> <features> <acpi/> <apic/> <pae/> </features> <clock offset='utc'/> <on_poweroff>destroy</on_poweroff> <on_reboot>restart</on_reboot> <on_crash>restart</on_crash> <devices> <emulator>/usr/libexec/qemu-kvm</emulator> <disk type='block' device='disk'> <driver name='qemu' type='raw' cache='none' io='native'/> <source dev='/dev/disk/by-path/ip-192.168.200.1:3260-iscsi-iqn.2012-02.net.mydomain.storage1:test1-lun-1'/> <target dev='vda' bus='virtio'/> <alias name='virtio-disk0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0'/> </disk> <interface type='bridge'> <mac address='52:54:00:5b:71:43'/> <source bridge='br0'/> <target dev='vnet5'/> <model type='virtio'/> <alias name='net0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/> </interface> <serial type='pty'> <source path='/dev/pts/6'/> <target port='0'/> <alias name='serial0'/> </serial> <console type='pty' tty='/dev/pts/6'> <source path='/dev/pts/6'/> <target type='serial' port='0'/> <alias name='serial0'/> </console> <input type='tablet' bus='usb'> <alias name='input0'/> </input> <input type='mouse' bus='ps2'/> <graphics type='vnc' port='5905' autoport='yes' listen='127.0.0.1'> <listen type='address' address='127.0.0.1'/> </graphics> <video> <model type='cirrus' vram='9216' heads='1'/> <alias name='video0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/> </video> <memballoon model='virtio'> <alias name='balloon0'/> <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/> </memballoon> </devices> </domain>
这看起来像是一个initrd的问题，请尝试在使用旧版本内核的情况下重build它：
mkinitrd /initramfs-2.6.32-220.23.1.el6.x86_64.img 2.6.32-220.23.1.el6.x86_64