kolla-ansible/doc/image-building.rst

Image building

The tools/build.py script in this repository is responsible for building docker images.

Guide

In general, you will build images like this:

$ tools/build.py

By default, the above command would build all images based on centos image.

If you want to change the base distro image, add -b:

$ tools/build.py -b ubuntu

There are following distros available for building images:

• fedora
• centos
• oraclelinux
• ubuntu

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

$ tools/build.py --push

If you want to build only keystone image, use the following command:

$ tools/build.py keystone

If you want to build multiple images e.g. keystone and nova, use the following command:

$ tools/build.py keystone nova

tools/build.py use kollaglue as default namespace. If you want to push images to your dockerhub, change the namespace like:

$ tools/build.py -n yourusername --push

To push images to local registry, use --registry flag like the following command:

tools/build.py --registry 172.22.2.81:4000 --push

To trigger buid.py to pull images from local registry, the Docker configuration needs to be modified. See Docker Insecure Registry Config.

The build script reads its configuration from /etc/kolla/kolla-build.conf or etc/kolla/kolla-build.conf. This is where to change the default settings.

Build OpenStack from Source

When building images, there are two methods of the OpenStack install. One is binary. Another is source. The binary means that OpenStack will be installed from apt/yum. And the source means that OpenStack will be installed from source code. The default method of the OpenStack install is binary. You can change it to source using the following command:

tools/build.py -t source

The locations of OpenStack source code are written in etc/kolla/kolla-build.conf. Now the source type support url and git. The etc/kolla/kolla-build.conf looks like:

[glance-base]
type = url
location = http://tarballs.openstack.org/glance/glance-master.tar.gz

[keystone]
type = git
location = https://github.com/openstack/keystone
reference = stable/kilo

To build RHEL containers, it is necessary to use the -i (include header) feature to include registration with RHN of the container runtime operating system. To obtain a RHN username/password/pool id, contact Red Hat.

First create a file called rhel-include:

RUN subscription-manager register --user=<user-name> --password=<password> \
&& subscription-manager attach --pool <pool-id>

Then build RHEL containers:

build -b rhel -i ./rhel-include

Known issues

1. Can't build base image because docker fails to install systemd.

   There are some issue between docker and AUFS. The simple workaround to avoid the issue is that add -s devicemapper to DOCKER_OPTS. Get more information about the issue from DockerBug.

Docker Local Registry

It is recommended to set up local registry for Kolla developers or deploying multinode. The reason using a local registry is deployment performance will operate at local network speeds, typically gigabit networking. Beyond performance considerations, the Operator would have full control over images that are deployed. If there is no local registry, nodes pull images from Docker Hub when images are not found in local caches.

Setting up Docker Local Registry

Running Docker registry is easy. Just use the following command:

docker run -d -p 4000:5000 --restart=always --name registry registry

The default port of Docker registry is 5000. But the 5000 port is also the port of keystone-api. To avoid conflict, use 4000 port as Docker registry port.

Now the Docker registry service is running.

Docker Insecure Registry Config

For docker to pull images, it is necessary to modify the Docker configuration. The guide assumes that the IP of the machine running Docker registry is 172.22.2.81.

In Ubuntu, add --insecure-registry 172.22.2.81:4000 to DOCKER_OPTS in /etc/default/docker.

In CentOS, uncomment INSECURE_REGISTRY and set INSECURE_REGISTRY to --insecure-registry 172.22.2.81:4000 in /etc/sysconfig/docker.

And restart the docker service.

To build and push images to local registry, use the following command:

tools/build.py --registry 172.22.2.81:4000 --push

Kolla-ansible with Local Registry

To make kolla-ansible pull images from local registry, set "docker_registry" to "172.22.2.81:4000" in "/etc/kolla/globals.yml". Make sure Docker is allowed to pull images from insecure registry. See Docker Insecure Registry Config.

Building behind a proxy

The build script supports augmenting the Dockerfiles under build via so called header and footer files. Statements in the header file are included at the top of the base image, while those in footer are included at the bottom of every Dockerfile in the build.

A common use case for this is to insert http_proxy settings into the images to fetch packages during build, and then unset them at the end to avoid having them carry through to the environment of the final images. Note however, it's not possible to drop the info completely using this method; it will still be visible in the layers of the image.

To use this feature, create a file called .header, with the following content for example:

ENV http_proxy=https://evil.corp.proxy:80
ENV https_proxy=https://evil.corp.proxy:80

Then create another file called .footer, with the following content:

ENV http_proxy=""
ENV https_proxy=""

Finally, pass them to the build script using the -i and -I flags:

tools/build.py -i .header -I .footer