lpack

lpack unpacks OCI images into CoW layers using either btrfs or lvm, according to a configuration in ./atom_config.yaml. A sample btrfs configuration looks like:

driver: "btrfs"
layoutdir: ~/oci
lofile: ~/btrfs.img
btrfsmount: ~/experiment

A sample lvm configuration is:

driver: "lvm"
vg: "atom"
lvbasedir: "~/lvm"

The shortest working configuration includes only the driver line, setting it to either lvm or btrfs. In this case, the OCI layout is ./oci, the loopback file is btrfs.img or lvm.img, the LV is stacker, the lv device is /dev/nbd0, and the layouts are mounted under ./btrfs or ./lvm.

This will be re-written as 'stacker' (in golang).

Installing

Since this is a proof of concept, installation is hacky:

mkdir -p /usr/share/atom
cp *.py *.sh /usr/share/atom
cp lpack /usr/bin

Trying it out

Setup a loopback device using

lpack setup

Tear it down using

lpack unsetup

Unpack the OCI layers using

lpack unpack

Use

lpack checkout <tag>

to check a tag out under ./btrfs/mounted or ./lvm/mounted.

You can then make changes to the rootfs under the mounted directory and check the changes in as a new tag using

lpack checkin<newtag>

If you do not provide a new tag, then YYYY-MM-DD_vN will be used, where YYYY-MM-DD is today's date, and N is a unique integer, starting with 1. For instance, 2017-09-17_v1.

TODO

This will be merged with 'genoci' and rewritten in golang as github.com/atom-deps/stacker.