Project News

Docker image metadata can be arbitrarily extended using the LABEL directive in a Dockerfile. This is a great way to annotate an image and enable automation:

• How to run or install an image
• Who built an image
• URLs for documentation or other support information

We’ve been encouraging the docker community to standardize these LABELs in an open source way through the Container Application Generic Labels repository. Recent pull requests added a new vendor directory for software companies (or FOSS projects) to document metadata that is specific to their particular needs.

As a point of reference, Red Hat released their LABEL metadata and image naming policy to the community. This might be a useful reference for other folks building their own metadata.

Have metadata for your project? Just submit a pull request to help create documentation about metadata your tooling or application depends on. Have questions? Ask on the atomic-devel mailing list, or create an issue in the GitHub repository.

A single Atomic Host is a fine place to run your containers, but these hosts are much more fun when bunched into clusters, a task that we can manage with the help of Kubernetes.

There are a lot of great guides for setting up a kubernetes cluster, but my favorite involves ansible and vagrant, and lives in the kubernetes contrib repository on Github.

This install method can be used with the libvirt, virtualbox or openstack vagrant providers. You can also use the ansible scripts on their own, if vagrant isn’t your thing.

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Next week, on Tuesday, September 22nd, the Fedora Cloud and CentOS Atomic special interest groups will be dabbling in test day fusion to put each projects’ Atomic Host Images through their paces.

On the Fedora side, we’ll be testing images based on the upcoming Fedora 23. On the CentOS side, we’ll test images from our latest release, as well as one or more development images featuring newer components atop the CentOS 7 base.

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It’s been a while when we announced move of atomic-reactor under Project Atomic.

Since the name is so cryptic, one could wonder about the purpose of the tool. Let’s go through a simple example…

What problem is atomic-reactor trying to solve?

Imagine Bob, a software engineer who would like to ship company’s products as containers. Bob’s company has already pretty complex infrastructure with build system, source code management, product deployment and delivery.

So Bob starts the work on integrating docker into company’s infrastructure.

Bob knows it’s so easy to build a docker image:

$ docker build --tag=product-X .

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Docker 1.8 fixes a long term problem with handling of command line options. It introduces the docker daemon command which segregates the global options from the daemon options.

Docker daemon is a background server side process that manages images and containers. It is a child of the init system e.g systemd and can be started using systemd unit files. For the purpose of this article we will using linux distribution fedora.

A system administrator can execute systemctl start docker to start the docker daemon.

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