migrateDockerRegistries

Migration tool to move docker images from one source repo to a destination repo

NOTE:

This is the first tool where I explicitely disable CGO (the "C" bindings). Please report any issue asap.

Overview

The software needs a tuple : sourceRegistry_destRegistry . The tuple is composed of an URL, a username and a password. All operations are against that tuple.

The software will look up all images + tags in the source part of the tupple, and compare that list with the one from the destination part of the tupple.

This means, that we need a way to define and work with these tuples, hence the concept of environments.

Environments

The idea behind environment

All tuple is defined in its own environment file. Those files are stored in $HOME/.config/JFG/migrateDockerRegistries/. A sample file is generated at run time, sample.json

By default, the software is using defaultEnv.json. You can override this with the -e flag, followed by a filename.

To create your own environment file, you need to run migrateDockerRegistries env add [FILENAME] (if FILENAME is omitted, defaultEnv.json is assumed). You will be prompted with the values to use. The password will be base64-encoded.

Why multiple environments ?

Again, as the software runs with tuples, you might wish to migrate docker images to-from multiple sources/targets. This is a way to let you keep (save) multiple configs in a single directory without having to overwrite your config file.

A sample environment file

{
  "Source Docker Registry": {
    "Name": "NEXUS",
    "url": "https://nexus:9820",
    "username": "jfgratton",
    "password": "HPTK21QOwFB5Uz-aweDk2xycPcJyo-hA"
  },
  "Destination Docker Registry": {
    "Name": "NAS",
    "url": "http://nas:5123",
    "username": "jfgratton",
    "password": "_qtWu01FKZ6RzoLeg_6Rkes_xNdSQl56"
  }
}

RUNNING the tool

It's very simple. Assuming you have a valid $HOME/.config/JFG/migrateDockerRegistries/defaultEnv.json. If you wish to use another environment, use -e FILENAME (no path.)

migrateDockerRegistries [-H HOST] [-e ENVFILE] {compare|ls} [-d] [-l] [-p] [-r].

The way tool works is quite simple :

All images + tags (default behaviour) are fetched from the source docker registry. The list is then written in a file named REPONAME.txt, NEXUS.txt, with the above environment file.
All images + tags (default behaviour) are fetched from the destination docker registry. The list is then written in a file named REPONAME.txt, NAS.txt, with the above environment file.
All images+tags present in NEXUS.txt but absent in NAS.txt will be written NEXUS-NAS.txt (also in JSON: NEXUS-NAS.json)

The behaviour of the tool can be modified with the following flags:

-H HOST: on which docker daemon to work on. It defaults on the local daemon, using unix sockets
-e ENVIRONMENTFILE : which environment file to take
-r : A .sh file named NEXUS-NAS.sh will be created with all commands needed to pull the source image and retag it
-l : will fetch only the 'latest' tag from the source repository (defaults to false)

if -r is unset (that is, is false), the following flags are ignored

-d : original image/tag is erased after retagging
-p : a docker push command is issued in the .sh file with the retagged image

A FAIR WARNING: Using the -r flag can be very, very consuming, storage-wise, especially on large remote registries. Use with caution

SEE FIXME-TODO.md on this

BUILDING the tool

From source

Again, quite simple... assuming that you have a suitable version of GO (see go.version, from the rootdir), all you need is, from the rootdir : cd src/ ; ./upgradeBuildDeps.sh && ./build.sh This assumes you have write permissions to /opt/bin, otherwise run build.sh with a target directory as parameter

From packages

AlpineLinux APK, Debian-based DEB or RedHat-based RPM will be provided once the software is working. See the Releases/Tags tab.

jeanfrancoisgratton / migrateDockerRegistries