OpenStack Compute (nova)

What's needed for disk hotplug in the guest?

Asked by justinsb

I'm trying to get iSCSI volumes working; I think it's almost there, I can attach the disk using virsh attach-disk on e.g. vdb, but I can't get the disk to show up in the guest without a reboot (but then it does show up!)

I'm running my own ubuntu guest image that I've built using vmbuilder; I've tried "modprobe acpiphp"; udev is running.

Anyone know what I'm missing to get this to work?

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Vish Ishaya (vishvananda) said : 		#1

it is usually acpiphp. Do you get any messages relating to acpiphp in the logs on the guest when you run the attach? Also check /proc/partitions to see if vdb is there but doesn't have a corresponding dev node.

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justinsb (justin-fathomdb) said : 		#2

Thanks for the advice: I started again with a clean VM, and it works. I may have hosed the previous VM when I was trying to get iSCSI attach to work at all. I've added acpiphp to /etc/modules as part of the disk preparation process.

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Vish Ishaya (vishvananda) said : 		#3

If you are attaching to vd*, you have to make sure you have the various virtio modules installed as well, especially virtio_blk

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Aimon Bustardo (aimonb) said : 		#4

Hi, I am very interested in this. justinsb can you provide some info on how you set this up? Are you doing this manually or programatically? This is functionality I would like to see directly in the OpenStack API somewhere..

Regards,

Aimon

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justinsb (justin-fathomdb) said : 		#5

Hi Aimon: iSCSI is still in development right now... you can see the code in my branch:
https://code.launchpad.net/~justin-fathomdb/nova/iscsi-volumes

And we're working on the general iSCSI design here - feel free to contribute to the discussion:
https://blueprints.launchpad.net/nova/+spec/iscsi-support

I believe that this is supposed to work currently using the normal code, using ATA-over-Ethernet (AoE), but I haven't tried it myself yet.

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Aimon Bustardo (aimonb) said : 		#6

Thanks justinb. I will read the spec and pitch in where I can.