Cinder volume from image can cause a full fs

[cloudnull]

In order to ensure that cinder is available at all times and does not suffer from 100% full disks due to building volumes from images the path /mnt/var/lib/cinder/conversion/ needs to be bind mounted to the host or the cinder_volume container needs to be built with a larger default LV size.

[jameswthorne]

Some additional info: https://gist.github.com/jameswthorne/78dc7fab6a83598aff85

[b3rn4rd0s]

We will need some documentation if this does not get fixed.

[hughsaunders]

From @jameswthorne's logs:

2014-10-24 12:26:22.901 23976 TRACE oslo.messaging.rpc.dispatcher Command: sudo cinder-rootwrap /etc/cinder/rootwrap.conf dd if=/dev/zero of=/dev/mapper/cinder--volumes-volume--d03e1fce--a2f4--466f--aa7b--a408f6c08c9f count=10240 bs=1M conv=fdatasync
2014-10-24 12:26:22.901 23976 TRACE oslo.messaging.rpc.dispatcher Exit code: 1
2014-10-24 12:26:22.901 23976 TRACE oslo.messaging.rpc.dispatcher Stdout: ''
2014-10-24 12:26:22.901 23976 TRACE oslo.messaging.rpc.dispatcher Stderr: "/bin/dd: error writing '/dev/mapper/cinder--volumes-volume--d03e1fce--a2f4--466f--aa7b--a408f6c08c9f': No space left on device\n204
9+0 records in\n2048+0 records out\n2147483648 bytes (2.1 GB) copied, 2.57972 s, 832 MB/s\n"

This failed DDing directly to LV, I'm not sure how adding space to /mnt/var/lib/cinder/conversion will help? Question is, why was DD only able to write just over 2GB to the device while LVS shows that the LV size is 10GB?

[hughsaunders]

I am going to discount the DD problem in @jameswthorne's post as I don't have enough information to determine the cause. This issue will now focus on adding space for cinder to convert images. James, please raise another issue if the DD problem persists.

[cloudnull]

@hughsaunders - the changes you have in your private repo seem sensible, at commit "22845a6" do you think you could PR them into the master for this issue or do you think we should bind mount back to the host?

[hughsaunders]

@cloudnull my commit doesn't work due to ansible/ansible#7844 so I need to refactor to avoid that issue :(

[hughsaunders]

Still working on this, but bumped into issue ansible/ansible#8705 (see: https://gist.github.com/hughsaunders/4082a3732b3bf807cec3#file-gistfile2-txt-L8). This was mostly due to me running ansible 1.7.2