# Image building

The `tools/build-docker-image` script in this repository is
responsible for building docker images.  It is symlinked as `./build`
inside each Docker image directory.

When creating new image directories, you can run the
`tools/update-build-links` scripts to install the `build` symlink
(this script will install the symlink anywhere it find a file named
`Dockerfile`).

## Workflow

In general, you will build images like this:

    $ cd docker/keystone
    $ ./build

By default, the above command would build
`kollaglue/centos-rdo-keystone:CID`, where `CID` is the current short
commit ID.  That is, given:

    $ git rev-parse HEAD
    76a16029006a2f5d3b79f1198d81acb6653110e9

The above command would generate
`kollaglue/centos-rdo-keystone:76a1602`.  This tagging is meant to
prevent developers from stepping on each other or on release images
during the development process.

To push the image after building, add `--push`:

    $ ./build --push

To use these images, you must specify the tag in your `docker run`
commands:

    $ docker run kollaglue/centos-rdo-keystone:76a1602

## Building releases

To build into the `latest` tag, add `--release`:

    $ ./build --release

Or to build and push:

    $ ./build --push --release

## Build all images at once

The `build-all-docker-images` script in the tools directory is a wrapper for
the `build-docker-image` that builds all images, as the name suggests, in the
correct order. It responds to the same options as `build-docker-image` with the
additional `--from` and `--to` options that allows building only images that
have changed between the specified git revisions.

For example, to build all images contained in docker directory and push new release:

    $ tools/build-all-docker-images --release --push

To build only images modified in test-branch along with their children:

    $ tools/build-all-docker-images --from master --to test-branch

## Configuration

The `build-docker-image` script will look for a file named `.buildconf`
in the image directory and in the top level of the repository.  You
can use this to set defaults, such as:

    NAMESPACE=larsks
    PREFIX=fedora-rdo-

This setting would cause images to be tagged into the `larsks/`
namespace and use Fedora as base image instead of the default CentOS.