Adding multiple Ephemeral Volumes to Compute Instance on OpenStack

[afritzler]

Hi guys,

is there a way to add multiple ephemeral volumes to a given instance?

nova boot <vm-name> --image <image-id> --flavor <flaovr-id> \ 
--nic net-id=<net-id> --availability-zone <availability-zone-name> \
--ephemeral size=<size>,format=<format_type> \
--ephemeral size=<size>,format=<format_type> \
... and so on

Of course your flavor has to have a big enough ephemeral size configured.

http://docs.openstack.org/cli-reference/content/novaclient_commands.html#novaclient_subcommand_boot

Regards,
Andreas

[jtopjian]

Hi there,

I didn't know you could do this. 😄

It looks like this works by passing the ephemeral disks to the block_device_mapping parameter of the Nova API:

"block_device_mapping_v2": [
    {
        "boot_index": 0,
        "delete_on_termination": true,
        "destination_type": "local",
        "source_type": "image",
        "uuid": "036fa6c1-b9c1-435c-9d70-83de40d4af96"
    },
    {
        "boot_index": -1,
        "delete_on_termination": true,
        "destination_type": "local",
        "guest_format": "ext4",
        "source_type": "blank",
        "volume_size": "1"
    },
    {
        "boot_index": -1,
        "delete_on_termination": true,
        "destination_type": "local",
        "guest_format": "ext4",
        "source_type": "blank",
        "volume_size": "1"
    }
],

This should be supported in Gophercloud, under the bootfromvolume extension. If this is true, then the Terraform OpenStack provider will need modified to allow more than one block_device block (right now it enforces only one under the assumption that it's a single bootable volume).

Thanks for reporting this. Hopefully we'll be able to get this enabled soon.

[afritzler]

Thanks for the update @jtopjian. Looking forward to the multiple block_device support.

[jtopjian]

Just a quick update: I have this working but need to get a few small changes into Gophercloud. If you're interested, here is the working code:

https://github.com/jtopjian/terraform/tree/jtopjian-openstack-multi-ephemeral
https://github.com/jtopjian/gophercloud/tree/jtopjian-multi-ephemeral

There might be minor changes to those two branches over time.

[afritzler]

Thanks a lot for the update @jtopjian!

[justinclayton]

@jtopjian I feel like my timing is very fortunate, as it looks like this is really close to being done. If I am reading this right, you merged #4288 yesterday, which was a prerequisite for you creating a PR for your jtopjian-openstack-multi-ephemeral branch (jtopjian/terraform@d681c25)?

[jtopjian]

@justinclayton Yep, all correct. 😄

The next step is to get rackspace/gophercloud#515 merged and then I'll be able to open a PR for jtopjian@d681c25.

[jtopjian]

@afritzler @justinclayton Hey guys, just a heads up that I opened #5131. If you can, please test and let me know if you have any problems or comments!

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