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containers / docker-lvm-plugin

Docker volume plugin for LVM volumes
GNU Lesser General Public License v3.0
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Remove volume if format fails #60

Closed angermueller closed 5 years ago

angermueller commented 5 years ago

Description

If you choose a volume size below 16M formatting with xfs will fail. Unfortunately the created logical volume is not removed. docker volume ls shows no volumes but creating it again will fail, even with a valid size, because the LV still exists.

Steps to reproduce

Try to create a volume below 16M (expecting an error): docker volume create --driver lvm --name example1 --opt size=8M --opt thinpool=volumes It fails with Error partitioning volume. Try to create a valid volume with same name (should work): docker volume create --driver lvm --name example1 --opt size=100M --opt thinpool=volumes This fails again Error creating volume.

Workaround

Remove the logical volume manually: sudo lvremove docker/example1

Additional Information

Docker Version: 18.06.1-ce Golang Version: go version go1.8.1 linux/amd64 Operating System: Linux node-1 4.9.0-8-amd64 #1 SMP Debian 4.9.110-3+deb9u4 (2018-08-21) x86_64 GNU/Linux XFS Version: xfsprogs/stable,stable,now 4.9.0+nmu1 amd64 LVM Version: lvm2/stable,stable,now 2.02.168-2 amd64

Syslog

docker-lvm-plugin[15210]: 2018/11/06 13:04:31 Entering go-plugins-helpers getPath docker-lvm-plugin[15210]: 2018/11/06 13:04:31 Entering go-plugins-helpers createPath docker-lvm-plugin[15210]: Create: lvcreate error: exit status 5 output Using default stripesize 64.00 KiB.#012 Logical Volume "example1" already exists in volume group "docker" dockerd[15225]: time="2018-11-06T13:04:31.182414415+01:00" level=error msg="Handler for POST /v1.38/volumes/create returned error: create example1: VolumeDriver.Create: Error creating volume"

shishir-a412ed commented 5 years ago

@angermueller

I tried this on Ubuntu 16.04. I am able to create a volume of size 13M. However when I try to create a volume of size 12M I run into your described issue.

To cover all supported distributions (Ubuntu, Fedora, CentOS), I think 16M of threshold seems fine. We can throw an error somewhere here: https://github.com/projectatomic/docker-lvm-plugin/blob/master/driver.go#L85

Saying "Error creating LVM volume, minimum expected size is 16M" Let me know if this works for you.

angermueller commented 5 years ago

The solution fits perfect for me, thanks for the reply! I made some experiments with Ubuntu 16.04. Formatting a xfs volume under 16M does not work for me there either. Error message for a volume with exact size of 15M: $> dd if=/dev/zero of=mytest bs=1048576 count=15 $> mkfs.xfs mytest agsize (3840 blocks) too small, need at least 4096 blocks

On the other hand I would suggest to implement also a cleanup procedure in case the formatting fails. I think the lines around https://github.com/projectatomic/docker-lvm-plugin/blob/master/driver.go#L116 seem to be a good way to use them again in the same file around line 149 or 157. What do you think?

Edit: I'm not into go, otherwise I would provide a merge request.