github.com/demonoid81/containerd@v1.3.4/snapshots/devmapper/README.md (about)

     1  ## Devmapper snapshotter
     2  
     3  Devmapper is a `containerd` snapshotter plugin that stores snapshots in ext4-formatted filesystem images
     4  in a devicemapper thin pool.
     5  
     6  ## Setup
     7  
     8  To make it work you need to prepare `thin-pool` in advance and update containerd's configuration file.
     9  This file is typically located at `/etc/containerd/config.toml`.
    10  
    11  Here's minimal sample entry that can be made in the configuration file:
    12  
    13  ```
    14  [plugins]
    15    ...
    16    [plugins.devmapper]
    17      pool_name = "containerd-pool"
    18      base_image_size = "128MB"
    19    ...
    20  ```
    21  
    22  The following configuration flags are supported:
    23  * `root_path` - a directory where the metadata will be available (if empty
    24    default location for `containerd` plugins will be used)
    25  * `pool_name` - a name to use for the devicemapper thin pool. Pool name
    26    should be the same as in `/dev/mapper/` directory
    27  * `base_image_size` - defines how much space to allocate when creating the base device
    28  
    29  Pool name and base image size are required snapshotter parameters.
    30  
    31  ## Run
    32  Give it a try with the following commands:
    33  
    34  ```bash
    35  ctr images pull --snapshotter devmapper docker.io/library/hello-world:latest
    36  ctr run --snapshotter devmapper docker.io/library/hello-world:latest test
    37  ```
    38  
    39  ## Requirements
    40  
    41  The devicemapper snapshotter requires `dmsetup` (>= 1.02.110) command line tool to be installed and
    42  available on your computer. On Ubuntu, it can be installed with `apt-get install dmsetup` command.