Xen users - Jul 2014 - Trying to set-up DomU CentOS 7, but get Warning: /dev/root does not exist

I'm trying to set-up a ContOS 7 DomU server. I have used the PXE set-up
images like I normally would for earlier versions of CentOS.

Here is my config file:-

name      = "centos7"
memory    = 2048
disk      = ['phy:/dev/xen6/centos7,xvda,w' ]
vif = [ 'mac=xx:xx:xx:xx:xx:xx' ]
kernel    = "/root/xen/centos7-64/vmlinuz"
ramdisk   = "/root/xen/centos7-64/initrd.img"
vcpus     = 2
on_reboot = 'destroy'
on_crash  = 'preserve'

Starting the DomU would normally take me to the non-graphical install.

However, with CentOS 7, boot crashes out with....

[  OK  ] Reached target Basic System.
dracut-initqueue[555]: Warning: Could not boot.
dracut-initqueue[555]: Warning: /dev/root does not exist
         Starting Dracut Emergency Shell...
Warning: /dev/root does not exist

Generating "/run/initramfs/rdsosreport.txt"


Entering emergency mode. Exit the shell to continue.
Type "journalctl" to view system logs.
You might want to save "/run/initramfs/rdsosreport.txt" to a USB stick
or /boot
after mounting them and attach it to a bug report.


dracut:/# 


Some googling suggests this is also a problem with USB install and is to do with
device labels, but I don't know what that means in my context.

Any suggestions on how to fix this or (at least work around it), would be much
appreciated.

Thanks,

Ian.


full DomU boot is:-

Parsing config from centos7-install
[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Initializing cgroup subsys cpuacct
[    0.000000] Linux version 3.10.0-123.el7.x86_64
(builder@kbuilder.dev.centos.org) (gcc version 4.8.2 20140120 (Red Hat 4.8.2-16)
(GCC) ) #1 SMP Mon Jun 30 12:09:22 UTC 2014
[    0.000000] Command line: 
[    0.000000] ACPI in unprivileged domain disabled
[    0.000000] e820: BIOS-provided physical RAM map:
[    0.000000] Xen: [mem 0x0000000000000000-0x000000000009ffff] usable
[    0.000000] Xen: [mem 0x00000000000a0000-0x00000000000fffff] reserved
[    0.000000] Xen: [mem 0x0000000000100000-0x000000007fffffff] usable
[    0.000000] NX (Execute Disable) protection: active
[    0.000000] DMI not present or invalid.
[    0.000000] No AGP bridge found
[    0.000000] e820: last_pfn = 0x80000 max_arch_pfn = 0x400000000
[    0.000000] init_memory_mapping: [mem 0x00000000-0x000fffff]
[    0.000000] init_memory_mapping: [mem 0x7fe00000-0x7fffffff]
[    0.000000] init_memory_mapping: [mem 0x7c000000-0x7fdfffff]
[    0.000000] init_memory_mapping: [mem 0x00100000-0x7bffffff]
[    0.000000] RAMDISK: [mem 0x0223f000-0x04390fff]
[    0.000000] NUMA turned off
[    0.000000] Faking a node at [mem 0x0000000000000000-0x000000007fffffff]
[    0.000000] Initmem setup node 0 [mem 0x00000000-0x7fffffff]
[    0.000000]   NODE_DATA [mem 0x7fc04000-0x7fc2afff]
[    0.000000] Zone ranges:
[    0.000000]   DMA      [mem 0x00001000-0x00ffffff]
[    0.000000]   DMA32    [mem 0x01000000-0xffffffff]
[    0.000000]   Normal   empty
[    0.000000] Movable zone start for each node
[    0.000000] Early memory node ranges
[    0.000000]   node   0: [mem 0x00001000-0x0009ffff]
[    0.000000]   node   0: [mem 0x00100000-0x7fffffff]
[    0.000000] SFI: Simple Firmware Interface v0.81 http://simplefirmware.org
[    0.000000] smpboot: Allowing 2 CPUs, 0 hotplug CPUs
[    0.000000] No local APIC present
[    0.000000] APIC: disable apic facility
[    0.000000] APIC: switched to apic NOOP
[    0.000000] PM: Registered nosave memory: [mem 0x000a0000-0x000fffff]
[    0.000000] e820: [mem 0x80000000-0xffffffff] available for PCI devices
[    0.000000] Booting paravirtualized kernel on Xen
[    0.000000] Xen version: 4.4.0 (preserve-AD)
[    0.000000] setup_percpu: NR_CPUS:5120 nr_cpumask_bits:2 nr_cpu_ids:2
nr_node_ids:1
[    0.000000] PERCPU: Embedded 29 pages/cpu @ffff88007d000000 s86592 r8192
d24000 u1048576
[    0.000000] Built 1 zonelists in Node order, mobility grouping on.  Total
pages: 515978
[    0.000000] Policy zone: DMA32
[    0.000000] Kernel command line: 
[    0.000000] PID hash table entries: 4096 (order: 3, 32768 bytes)
[    0.000000] xsave: enabled xstate_bv 0x3, cntxt size 0x240
[    0.000000] Checking aperture...
[    0.000000] No AGP bridge found
[    0.000000] Memory: 2006356k/2097152k available (6105k kernel code, 388k
absent, 90408k reserved, 4065k data, 1584k init)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
[    0.000000] Hierarchical RCU implementation.
[    0.000000]     RCU restricting CPUs from NR_CPUS=5120 to nr_cpu_ids=2.
[    0.000000]     Experimental no-CBs for all CPUs
[    0.000000]     Experimental no-CBs CPUs: 0-1.
[    0.000000] NR_IRQS:327936 nr_irqs:288 16
[    0.000000] Console: colour dummy device 80x25
[    0.000000] console [tty0] enabled
[    0.000000] console [hvc0] enabled
[    0.000000] allocated 8388608 bytes of page_cgroup
[    0.000000] please try 'cgroup_disable=memory' option if you
don't want memory cgroups
[    0.000000] installing Xen timer for CPU 0
[    0.000000] tsc: Detected 2893.500 MHz processor
[    0.001000] Calibrating delay loop (skipped), value calculated using timer
frequency.. 5787.00 BogoMIPS (lpj=2893500)
[    0.001000] pid_max: default: 32768 minimum: 301
[    0.001000] Security Framework initialized
[    0.001000] SELinux:  Initializing.
[    0.001000] Dentry cache hash table entries: 262144 (order: 9, 2097152 bytes)
[    0.001000] Inode-cache hash table entries: 131072 (order: 8, 1048576 bytes)
[    0.001000] Mount-cache hash table entries: 4096
[    0.001135] Initializing cgroup subsys memory
[    0.001148] Initializing cgroup subsys devices
[    0.001152] Initializing cgroup subsys freezer
[    0.001155] Initializing cgroup subsys net_cls
[    0.001159] Initializing cgroup subsys blkio
[    0.001162] Initializing cgroup subsys perf_event
[    0.001166] Initializing cgroup subsys hugetlb
[    0.001215] ENERGY_PERF_BIAS: Set to 'normal', was
'performance'
[    0.001215] ENERGY_PERF_BIAS: View and update with x86_energy_perf_policy(8)
[    0.001222] CPU: Physical Processor ID: 0
[    0.001225] CPU: Processor Core ID: 0
[    0.001230] Last level iTLB entries: 4KB 512, 2MB 0, 4MB 0
[    0.001230] Last level dTLB entries: 4KB 512, 2MB 32, 4MB 32
[    0.001230] tlb_flushall_shift: 6
[    0.022300] ftrace: allocating 23383 entries in 92 pages
[    0.027088] cpu 0 spinlock event irq 17
[    0.027130] Performance Events: unsupported p6 CPU model 42 no PMU driver,
software events only.
[    0.028029] NMI watchdog: disabled (cpu0): hardware events not enabled
[    0.028084] installing Xen timer for CPU 1
[    0.028095] cpu 1 spinlock event irq 24
[    0.028118] SMP alternatives: switching to SMP code
[    0.047691] Brought up 2 CPUs
[    0.047799] devtmpfs: initialized
[    0.047959] EVM: security.selinux
[    0.047965] EVM: security.ima
[    0.047969] EVM: security.capability
[    0.049423] atomic64 test passed for x86-64 platform with CX8 and with SSE
[    0.049454] xen:grant_table: Grant tables using version 2 layout
[    0.049481] Grant table initialized
[    0.049517] NET: Registered protocol family 16
[    0.050055] PCI: setting up Xen PCI frontend stub
[    0.051077] bio: create slab <bio-0> at 0
[    0.051077] ACPI: Interpreter disabled.
[    0.051077] xen:balloon: Initialising balloon driver
[    0.052009] xen_balloon: Initialising balloon driver
[    0.052030] vgaarb: loaded
[    0.052068] SCSI subsystem initialized
[    0.052068] usbcore: registered new interface driver usbfs
[    0.052068] usbcore: registered new interface driver hub
[    0.052068] usbcore: registered new device driver usb
[    0.052068] PCI: System does not support PCI
[    0.052068] PCI: System does not support PCI
[    0.053068] NetLabel: Initializing
[    0.053072] NetLabel:  domain hash size = 128
[    0.053074] NetLabel:  protocols = UNLABELED CIPSOv4
[    0.053083] NetLabel:  unlabeled traffic allowed by default
[    0.053088] Switching to clocksource xen
[    0.056866] pnp: PnP ACPI: disabled
[    0.058849] NET: Registered protocol family 2
[    0.058969] TCP established hash table entries: 16384 (order: 5, 131072
bytes)
[    0.059023] TCP bind hash table entries: 16384 (order: 6, 262144 bytes)
[    0.059066] TCP: Hash tables configured (established 16384 bind 16384)
[    0.059084] TCP: reno registered
[    0.059093] UDP hash table entries: 1024 (order: 3, 32768 bytes)
[    0.059105] UDP-Lite hash table entries: 1024 (order: 3, 32768 bytes)
[    0.059144] NET: Registered protocol family 1
[    0.059186] Unpacking initramfs...
[    3.252164] Freeing initrd memory: 34120k freed
[    3.257997] platform rtc_cmos: registered platform RTC device (no PNP device
found)
[    3.258508] microcode: CPU0 sig=0x206a7, pf=0x2, revision=0x26
[    3.258632] microcode: CPU1 sig=0x206a7, pf=0x2, revision=0x26
[    3.258722] microcode: Microcode Update Driver: v2.00
<tigran@aivazian.fsnet.co.uk>, Peter Oruba
[    3.258934] futex hash table entries: 512 (order: 3, 32768 bytes)
[    3.258946] Initialise system trusted keyring
[    3.258982] audit: initializing netlink socket (disabled)
[    3.258994] type=2000 audit(1405087133.283:1): initialized
[    3.276836] HugeTLB registered 2 MB page size, pre-allocated 0 pages
[    3.277986] zbud: loaded
[    3.278300] VFS: Disk quotas dquot_6.5.2
[    3.278356] Dquot-cache hash table entries: 512 (order 0, 4096 bytes)
[    3.278496] msgmni has been set to 3985
[    3.278536] Key type big_key registered
[    3.279480] alg: No test for stdrng (krng)
[    3.279504] NET: Registered protocol family 38
[    3.279508] Key type asymmetric registered
[    3.279510] Asymmetric key parser 'x509' registered
[    3.279536] Block layer SCSI generic (bsg) driver version 0.4 loaded (major
252)
[    3.279581] io scheduler noop registered
[    3.279584] io scheduler deadline registered (default)
[    3.279608] io scheduler cfq registered
[    3.279661] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[    3.279674] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
[    3.280042] Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
[    3.280404] Non-volatile memory driver v1.3
[    3.280409] Linux agpgart interface v0.103
[    3.280472] crash memory driver: version 1.1
[    3.280487] rdac: device handler registered
[    3.280525] hp_sw: device handler registered
[    3.280529] emc: device handler registered
[    3.280531] alua: device handler registered
[    3.280557] libphy: Fixed MDIO Bus: probed
[    3.280606] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI)
Driver
[    3.280613] ehci-pci: EHCI PCI platform driver
[    3.280620] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
[    3.280623] ohci-pci: OHCI PCI platform driver
[    3.280629] uhci_hcd: USB Universal Host Controller Interface driver
[    3.280662] usbcore: registered new interface driver usbserial
[    3.280669] usbcore: registered new interface driver usbserial_generic
[    3.280677] usbserial: USB Serial support registered for generic
[    3.280691] i8042: PNP: No PS/2 controller found. Probing ports directly.
[    4.289340] i8042: No controller found
[    4.289451] mousedev: PS/2 mouse device common for all mice
[    4.349782] rtc_cmos rtc_cmos: rtc core: registered rtc_cmos as rtc0
[    4.350100] rtc_cmos: probe of rtc_cmos failed with error -38
[    4.350128] hidraw: raw HID events driver (C) Jiri Kosina
[    4.350192] usbcore: registered new interface driver usbhid
[    4.350195] usbhid: USB HID core driver
[    4.350217] drop_monitor: Initializing network drop monitor service
[    4.350276] TCP: cubic registered
[    4.350279] Initializing XFRM netlink socket
[    4.350342] NET: Registered protocol family 10
[    4.350451] NET: Registered protocol family 17
[    4.350590] Loading compiled-in X.509 certificates
[    4.350614] Loaded X.509 cert 'CentOS Linux kpatch signing key:
ea0413152cde1d98ebdca3fe6f0230904c9ef717'
[    4.350630] Loaded X.509 cert 'CentOS Linux Driver update signing key:
7f421ee0ab69461574bb358861dbe77762a4201b'
[    4.351108] Loaded X.509 cert 'CentOS Linux kernel signing key:
bc83d0fe70c62fab1c58b4ebaa95e3936128fcf4'
[    4.351121] registered taskstats version 1
[    4.354567] Key type trusted registered
[    4.360087] Key type encrypted registered
[    4.363316] IMA: No TPM chip found, activating TPM-bypass!
[    4.363373] xenbus_probe_frontend: Device with no driver: device/vbd/51712
[    4.363377] xenbus_probe_frontend: Device with no driver: device/vif/0
[    4.363451] drivers/rtc/hctosys.c: unable to open rtc device (rtc0)
[    4.364010] Freeing unused kernel memory: 1584k freed
[    4.368413] systemd[1]: systemd 208 running in system mode. (+PAM +LIBWRAP
+AUDIT +SELINUX +IMA +SYSVINIT +LIBCRYPTSETUP +GCRYPT +ACL +XZ)
[    4.368492] systemd[1]: Detected virtualization 'xen'.
[    4.368499] systemd[1]: Running in initial RAM disk.

Welcome to CentOS Linux 7 (Core) dracut-033-161.el7 (Initramfs)!

[    4.368646] systemd[1]: No hostname configured.
[    4.368655] systemd[1]: Set hostname to <localhost>.
[    4.368750] systemd[1]: Initializing machine ID from random generator.
[    4.403379] systemd[1]: Starting -.slice.
[  OK  ] Created slice -.slice.
[    4.403822] systemd[1]: Created slice -.slice.
[    4.403908] systemd[1]: Starting System Slice.
[  OK  ] Created slice System Slice.
[    4.404105] systemd[1]: Created slice System Slice.
[    4.404183] systemd[1]: Starting Slices.
[  OK  ] Reached target Slices.
[    4.404260] systemd[1]: Reached target Slices.
[    4.404333] systemd[1]: Starting Timers.
[  OK  ] Reached target Timers.
[    4.404406] systemd[1]: Reached target Timers.
[    4.404481] systemd[1]: Starting Encrypted Volumes.
[  OK  ] Reached target Encrypted Volumes.
[    4.404557] systemd[1]: Reached target Encrypted Volumes.
[    4.404630] systemd[1]: Starting Journal Socket.
[  OK  ] Listening on Journal Socket.
[    4.404816] systemd[1]: Listening on Journal Socket.
[    4.405218] systemd[1]: Starting dracut cmdline hook...
         Starting dracut cmdline hook...
[    4.406387] systemd[1]: Started Load Kernel Modules.
[    4.406415] systemd[1]: Starting Setup Virtual Console...
         Starting Setup Virtual Console...
[    4.407540] systemd[1]: Starting Journal Service...
         Starting Journal Service...
[  OK  ] Started Journal Service.
[    4.408841] systemd[1]: Started Journal Service.
[  OK  ] Listening on udev Kernel Socket.
[  OK  ] Listening on udev Control Socket.
[  OK  ] Reached target Sockets.
         Starting Create list of required static device nodes...rrent kernel...
         Starting Apply Kernel Variables...
         Starting Device-Mapper Multipath Device Controller...
[  OK  ] Reached target Swap.
[    4.422515] systemd-journald[84]: Vacuuming done, freed 0 bytes
[  OK  ] Reached target Local File Systems.
[    4.432606] device-mapper: uevent: version 1.0.3
[    4.432673] device-mapper: ioctl: 4.27.0-ioctl (2013-10-30) initialised:
dm-devel@redhat.com
[  OK  ] Started Setup Virtual Console.
[    4.494910] device-mapper: multipath: version 1.6.0 loaded
[  OK  ] Started Apply Kernel Variables.
[  OK  ] Started Create list of required static device nodes ...current kernel.
         Starting Create static device nodes in /dev...
[  OK  ] Started Create static device nodes in /dev.
[  OK  ] Started Device-Mapper Multipath Device Controller.
[    4.546601] BIOS EDD facility v0.16 2004-Jun-25, 0 devices found
[    4.546610] EDD information not available.
[  OK  ] Started dracut cmdline hook.
         Starting dracut pre-udev hook...
[    5.166524] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    5.174260] Loading iSCSI transport class v2.0-870.
[    5.179808] iscsi: registered transport (tcp)
[    5.250500] Floppy drive(s): fd0 is unknown type 15 (usb?), fd1 is unknown
type 15 (usb?)
[    5.250523] floppy0: Unable to grab IRQ6 for the floppy driver
[    5.263007] BIOS EDD facility v0.16 2004-Jun-25, 0 devices found
[    5.263021] EDD information not available.
[    5.276014] No iBFT detected.
[    5.281463] md: raid0 personality registered for level 0
[    5.288251] md: raid1 personality registered for level 1
[    5.293992] async_tx: api initialized (async)
[    5.295727] xor: measuring software checksum speed
[    5.305056]    prefetch64-sse:  8920.000 MB/sec
[    5.315053]    generic_sse: 14824.000 MB/sec
[    5.315056] xor: using function: generic_sse (14824.000 MB/sec)
[    5.334056] raid6: sse2x1    7730 MB/s
[    5.351058] raid6: sse2x2    9695 MB/s
[    5.368054] raid6: sse2x4   11238 MB/s
[    5.368058] raid6: using algorithm sse2x4 (11238 MB/s)
[    5.368060] raid6: using ssse3x2 recovery algorithm
[    5.372777] md: raid6 personality registered for level 6
[    5.372783] md: raid5 personality registered for level 5
[    5.372786] md: raid4 personality registered for level 4
[    5.385479] md: raid10 personality registered for level 10
[    5.390027] md: linear personality registered for level -1
[    5.422623] device-mapper: multipath round-robin: version 1.0.0 loaded
[    5.438366] sha256_ssse3: Using SSSE3 optimized SHA-256 implementation
[    5.486012] RPC: Registered named UNIX socket transport module.
[    5.486026] RPC: Registered udp transport module.
[    5.486031] RPC: Registered tcp transport module.
[    5.486035] RPC: Registered tcp NFSv4.1 backchannel transport module.
[  OK  ] Started dracut pre-udev hook.
         Starting udev Kernel Device Manager...
[    5.623318] systemd-udevd[430]: starting version 208
[  OK  ] Started udev Kernel Device Manager.
         Starting dracut pre-trigger hook...
[    5.805025] xen_netfront: Initialising Xen virtual ethernet driver
[    5.817651] alg: No test for crc32 (crc32-pclmul)
[    5.832691] blkfront: xvda: flush diskcache: enabled; persistent grants:
disabled; indirect descriptors: disabled;
[    5.834035]  xvda: unknown partition table
[    5.834341] Setting capacity to 62914560
[    5.834349] xvda: detected capacity change from 0 to 32212254720
[  OK  ] Started dracut pre-trigger hook.
         Starting udev Coldplug all Devices...
         Mounting Configuration File System...
[  OK  ] Started udev Coldplug all Devices.
         Starting dracut initqueue hook...
         Starting Show Plymouth Boot Screen...
[  OK  ] Mounted Configuration File System.
[  OK  ] Reached target System Initialization.
[  OK  ] Started Show Plymouth Boot Screen.
[  OK  ] Reached target Paths.
[  OK  ] Reached target Basic System.
dracut-initqueue[555]: Warning: Could not boot.
[  OK  ] Started Show Plymouth Boot Screen.
[  OK  ] Reached target Paths.
[  OK  ] Reached target Basic System.
dracut-initqueue[555]: Warning: Could not boot.
dracut-initqueue[555]: Warning: /dev/root does not exist
         Starting Dracut Emergency Shell...
Warning: /dev/root does not exist

Generating "/run/initramfs/rdsosreport.txt"


Entering emergency mode. Exit the shell to continue.
Type "journalctl" to view system logs.
You might want to save "/run/initramfs/rdsosreport.txt" to a USB stick
or /boot
after mounting them and attach it to a bug report.


dracut:/# 


xl info:

release                : 3.2.0-54-generic
version                : #82-Ubuntu SMP Tue Sep 10 20:08:42 UTC 2013
machine                : x86_64
nr_cpus                : 2
max_cpu_id             : 1
nr_nodes               : 1
cores_per_socket       : 2
threads_per_core       : 1
cpu_mhz                : 2893
hw_caps                :
bfebfbff:28100800:00000000:00003f00:059ae3bf:00000000:00000001:00000000
virt_caps              : hvm
total_memory           : 16241
free_memory            : 9248
sharing_freed_memory   : 0
sharing_used_memory    : 0
outstanding_claims     : 0
free_cpus              : 0
xen_major              : 4
xen_minor              : 4
xen_extra              : .0
xen_version            : 4.4.0
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : 
xen_commandline        : placeholder dom0_mem=1024M,max:1024M
cc_compiler            : gcc (Ubuntu/Linaro 4.6.3-1ubuntu5) 4.6.3
cc_compile_by          : root
cc_compile_domain      : 
cc_compile_date        : Wed Apr 30 18:17:39 BST 2014
xend_config_format     : 4