docker2fl

docker2fl is a tool to extract docker images and convert them to flist using rfs tool.

Build

To build docker2fl make sure you have rust installed then run the following commands:

# this is needed to be run once to make sure the musl target is installed
rustup target add x86_64-unknown-linux-musl

# build the binary
cargo build --release --target=x86_64-unknown-linux-musl

the binary will be available under ./target/x86_64-unknown-linux-musl/release/docker2fl you can copy that binary then to /usr/bin/ to be able to use from anywhere on your system.

sudo mv ./target/x86_64-unknown-linux-musl/release/docker2fl /usr/bin/

Stores

A store in where the actual data lives. A store can be as simple as a directory on your local machine in that case the files on the fl are only 'accessible' on your local machine. A store can also be a zdb running remotely or a cluster of zdb. Right now only dir, zdb and s3 stores are supported but this will change in the future to support even more stores.

Usage

Creating an fl

docker2fl -i redis -s <store-specs>

This tells docker2fl to create an fl named redis-latest.fl using the store defined by the url <store-specs> and upload all the files under the temp docker directory that include exported docker image recursively.

The simplest form of <store-specs> is a url. the store url defines the store to use. Any url has a schema that defines the store type. Right now we have support only for:

• dir: dir is a very simple store that is mostly used for testing. A dir store will store the fs blobs in another location defined by the url path. An example of a valid dir url is dir:///tmp/store
• zdb: zdb is a append-only key value store and provides a redis like API. An example zdb url can be something like zdb://<hostname>[:port][/namespace]

• s3: aws-s3 is used for storing and retrieving large amounts of data (blobs) in buckets (directories). An example s3://<username>:<password>@<host>:<port>/<bucket-name>

  region is an optional param for s3 stores, if you want to provide one you can add it as a query to the url ?region=<region-name>

<store-specs> can also be of the form <start>-<end>=<url> where start and end are a hex bytes for partitioning of blob keys. rfs will then store a set of blobs on the defined store if they blob key falls in the [start:end] range (inclusive).

If the start-end range is not provided a 00-FF range is assume basically a catch all range for the blob keys. In other words, all blobs will be written to that store.

This is only useful because docker2fl can accept multiple stores on the command line with different and/or overlapping ranges.

For example -s 00-80=dir:///tmp/store0 -s 81-ff=dir://tmp/store1 means all keys that has prefix byte in range [00-80] will be written to /tmp/store0 all other keys 00-ff will be written to store1.

The same range can appear multiple times, which means the blob will be replicated to all the stores that matches its key prefix.

To quickly test this operation

docker2fl -i redis -s "dir:///tmp/store0"

this command will use redis image and effectively create the redis.fl and store (and shard) the blobs across the location /tmp/store0.

#docker2fl --help

Usage: docker2fl [OPTIONS] --image-name <IMAGE_NAME>
Options:
      --debug...
          enable debugging logs
  -i, --image-name <IMAGE_NAME>
          name of the docker image to be converted to flist
  -s, --store <STORE>
          store url for rfs in the format [xx-xx=]<url>. the range xx-xx is optional and used for sharding. the URL is per store type, please check docs for more information
  -h, --help
          Print help
  -V, --version
          Print version