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How would I tell a xen pvm that its disk is not vda but xvda?

asked 2015-03-22 16:34:05 -0500

mrbriancollins gravatar image

updated 2015-03-27 10:29:33 -0500

How would I tell a vm that its disk is not vda but xvda? I have another question open but seems I can solve that question by asking this one.

I just need to figure out how to get this peice in the config referenced above to use blktap instead of blktap2. <driver name="tap2" type="raw"/> also its addressing sda instead of xvda....

<disk type='file' device='disk'>
  <driver name='tap2' type='raw'/>
  <source file='/var/lib/nova/instances/152bd71a-4f8e-4781-b397-77f95776aa7d/disk'/>
  <target dev='sda' bus='scsi'/>

I am not positive but I believe this should be:

<disk type="file" device="disk"> 
 <driver name="tap" type="raw"/> 
 <source file="/var/lib/nova/instances/152bd71a-4f8e-4781-b397-77f95776aa7d/disk"/>
 <target dev="xvda" bus="scsi"/> 

I just don't know how..... From the xend.log:

    (args, rc, out, err))
TapdiskException: ('create', '-aaio:/var/lib/nova/instances/e0af3d11-7307-4465-a582-80102dba62bd/disk') failed (55808 blktap kernel module not installed )
[2015-03-21 03:29:38 1007] INFO (XendDomain:1126) Domain instance-00000036 (e0af3d11-7307-4465-a582-80102dba62bd) deleted.
[2015-03-23 14:42:57 1007] DEBUG (XendDomainInfo:260) XendDomainInfo.createDormant({'vcpus_params': {'cap': 0, 'weight': 256}, 'PV_args': '', 'features': '', 'cpus': [[], [], [], []], 'use_tmp_kernel': False, 'devices': {'d1b6adf7-ac28-9567-2a5c-b8beb0ede5e2': ('vkbd', {'uuid': 'd1b6adf7-ac28-9567-2a5c-b8beb0ede5e2'}), '12fd6118-4a0e-e4d7-7861-f433b65c3f4b': ('vfb', {'vncunused': '1', 'other_config': {'vncunused': '1', 'vnclisten': '', 'keymap': 'en-us'}, 'vnc': 1, 'uuid': '12fd6118-4a0e-e4d7-7861-f433b65c3f4b', 'vnclisten': '', 'keymap': 'en-us'}), 'ccb71f12-9018-1085-5897-1901b07273d8': ('vif', {'bridge': 'qbrc00bf965-c4', 'mac': 'fa:16:3e:75:dc:40', 'script': 'vif-bridge', 'uuid': 'ccb71f12-9018-1085-5897-1901b07273d8', 'vifname': 'tapc00bf965-c4'}), '29247b91-8fec-b90a-d125-7a4cfb754d56': ('tap2', {'bootable': 1, 'uname': 'tap2:aio:/var/lib/nova/mnt/b691535f469d00f57eac8f5b0e6fd3b5/volume-975b7e4f-1271-43e1-9aa4-2d5a0721b54b', 'mode': 'w', 'dev': 'vda', 'uuid': '29247b91-8fec-b90a-d125-7a4cfb754d56'})}, 'memory_sharing': 0, 'superpages': 0, 'VCPUs_live': 1, 'PV_bootloader': '', 'actions_after_crash': 'destroy', 'vbd_refs': ['29247b91-8fec-b90a-d125-7a4cfb754d56'], 'PV_ramdisk': '', 'is_control_domain': False, 'name_label': 'instance-00000038', 'VCPUs_at_startup': 1, 'HVM_boot_params': {}, 'platform': {'device_model': '/usr/lib/xen/bin/qemu-dm', 'tsc_mode': 0, 'nomigrate': 0, 'localtime': '0'}, 'PV_kernel': '', 'console_refs': ['12fd6118-4a0e-e4d7-7861-f433b65c3f4b'], 'on_xend_stop': 'ignore', 'pool_name': 'Pool-0', 'memory_static_min': 0, 'HVM_boot_policy': '', 'description': '', 'VCPUs_max': 4, 'memory_static_max': 8589934592, 'actions_after_shutdown': 'destroy', 'use_tmp_ramdisk': False, 'on_xend_start': 'ignore', 'memory_dynamic_max': 8589934592, 'actions_after_suspend': '', 'is_a_template': False, 'PV_bootloader_args': '', 'memory_dynamic_min': 8589934592, 'uuid': '20444b5b-539a-4004-b972-8e077a6df819', 'shadow_memory': 0, 'target': 0, 'vcpu_avail': 15, 'other_config': {}, 'auto_power_on': False, 'actions_after_reboot': 'restart', 'Description': '', 'vif_refs': ['ccb71f12-9018-1085-5897-1901b07273d8']})
[2015-03-23 14:42:57 1007] DEBUG (XendDomain:1036) Creating new managed domain: instance-00000038
[2015-03-23 14:42:57 1007] DEBUG (SrvDomain:76) Starting domain instance-00000038 False
[2015-03-23 14:42:57 1007] DEBUG (XendDomainInfo:2499) XendDomainInfo.constructDomain
[2015-03-23 14:42:57 1007] DEBUG (balloon:187) Balloon: 2101528 KiB free; need 16384; done.
[2015-03-23 14:42:57 1007] DEBUG (XendDomain:476) Adding Domain: 5
[2015-03-23 14:42:57 1007] DEBUG (XendDomainInfo:2842) XendDomainInfo.initDomain: 5 256
[2015-03-23 14:42:57 1007] ERROR (XendBootloader:43) Disk isn't accessible
[2015-03-23 14:42:57 1007] ERROR (XendDomainInfo:488) VM start failed
Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/xen/xend/", line 474, in start
    XendTask.log_progress(31, 60, self._initDomain)
  File "/usr/lib64/python2.7/site-packages/xen/xend/", line 209, in log_progress
    retval = func(*args, **kwds)
  File "/usr/lib64/python2.7/site-packages/xen/xend/", line 2844, in _initDomain
  File "/usr/lib64/python2.7/site-packages/xen/xend/", line 3291, in _configureBootloader
    bootloader_args, kernel, ramdisk, args ...
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answered 2015-07-28 14:02:41 -0500

BuildGuru gravatar image

Xen creates VMs with Xvda when they are in PV mode by default. They are only vda if the VM is running in HVM mode. You can force PV mode by using XE templates and complimenting it with ISO. I had a similar problem when provisioning the boot drives for instances. Now i am running into a similar thing with Cinder where i need to createpv under /sdb1 not /xsdb1

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Asked: 2015-03-22 16:34:05 -0500

Seen: 990 times

Last updated: Jul 28 '15