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containerd/snapshots/devmapper
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Eric Ren a3685262fe snapshots/devmapper: do not stop snapshot GC when one snapshot removing fails 
Snapshots GC takes use of pruneBranch() function to remove snapshots,
but GC will stop if snapshotter.Remove() returns error and the error
number is not ErrFailedPrecondition. This results in thousands of
dm snapshots not deleted if one snapshot is not deleted, due to
errors like "contains a filesystem in use".

So return ErrFailedPrecondition error number in Remove() function where
appropriate, and let GC process go on collecting other snapshots.

Fix: #3923
Signed-off-by: Eryu Guan <eguan@linux.alibaba.com>
Signed-off-by: Eric Ren <renzhen.rz@linux.alibaba.com>
2020-02-29 13:32:48 +08:00
..
dmsetup
snapshots/devmapper: deactivate thin device after committed
2019-05-09 10:58:21 +08:00
losetup
Make tests less flaky
2020-01-30 09:57:34 -08:00
config_test.go
devmapper: don't create or reload thin-pool from snapshotter
2019-02-21 16:26:46 -08:00
config.go
devmapper: async remove device using Cleanup
2020-02-29 13:32:48 +08:00
device_info.go
Better error recovery in devmapper
2019-07-30 15:17:17 -07:00
metadata_test.go
Mark faulty devices
2019-08-05 12:05:36 -07:00
metadata.go
devmapper: async remove device using Cleanup
2020-02-29 13:32:48 +08:00
pool_device_test.go
devmapper: activate dm device if snap device marked as activated
2019-08-23 10:19:28 +08:00
pool_device.go
devmapper: async remove device using Cleanup
2020-02-29 13:32:48 +08:00
README.md
devmapper: async remove device using Cleanup
2020-02-29 13:32:48 +08:00
snapshotter_test.go
devmapper: implement Usage
2019-03-27 14:50:12 -07:00
snapshotter.go
snapshots/devmapper: do not stop snapshot GC when one snapshot removing fails
2020-02-29 13:32:48 +08:00

README.md

Devmapper snapshotter

Devmapper is a containerd snapshotter plugin that stores snapshots in ext4-formatted filesystem images in a devicemapper thin pool.

Setup

To make it work you need to prepare thin-pool in advance and update containerd's configuration file. This file is typically located at /etc/containerd/config.toml.

Here's minimal sample entry that can be made in the configuration file:

[plugins]
  ...
  [plugins.devmapper]
    pool_name = "containerd-pool"
    base_image_size = "8192MB"
  ...

The following configuration flags are supported:

  • root_path - a directory where the metadata will be available (if empty default location for containerd plugins will be used)
  • pool_name - a name to use for the devicemapper thin pool. Pool name should be the same as in /dev/mapper/ directory
  • base_image_size - defines how much space to allocate when creating the base device
  • async_remove - flag to async remove device using snapshot GC's cleanup callback

Pool name and base image size are required snapshotter parameters.

Run

Give it a try with the following commands:

ctr images pull --snapshotter devmapper docker.io/library/hello-world:latest
ctr run --snapshotter devmapper docker.io/library/hello-world:latest test

Requirements

The devicemapper snapshotter requires dmsetup (>= 1.02.110) command line tool to be installed and available on your computer. On Ubuntu, it can be installed with apt-get install dmsetup command.