Handy Search Engine for Docker Hub Images

http://soaphub.org/imagehub/ provides a nice way to search Docker Hub. You can search for strings in name spaces, and the result also displays what architectures the image is backed by.

ClefOS is official

Or more precisely, ClefOS is an official image. Official image means, it is part of curated content on Docker Hub. It is also (AFAIK) the first official image that has no support yet for other platforms. Well, this might be a dubious comparison since it is actually an equivalent to CentOS which does not have any s390x backing. ClefOS can't be named CentOS, since Neale Ferguson and company at Sine Nomine Associates are not part of the CentOS organization. However, as you can see it is very closely following it:

$ docker run -ti clefos
Unable to find image 'clefos:latest' locally
latest: Pulling from library/clefos
26dbd8e1d5ff: Pull complete
Digest: sha256:8e89216b23e7a5716a7e31de352ed777769738d258a1e20cc9cff06e39316717
Status: Downloaded newer image for clefos:latest
bash-4.2# cat /etc/os-release
NAME="CentOS Linux"
VERSION="7 (Core)"
ID="centos"
ID_LIKE="rhel fedora"
VERSION_ID="7"
PRETTY_NAME="CentOS Linux 7 (Core)"
ANSI_COLOR="0;31"
CPE_NAME="cpe:/o:centos:centos:7"
HOME_URL="https://www.centos.org/"
BUG_REPORT_URL="https://bugs.centos.org/"

CENTOS_MANTISBT_PROJECT="CentOS-7"
CENTOS_MANTISBT_PROJECT_VERSION="7"
REDHAT_SUPPORT_PRODUCT="centos"
REDHAT_SUPPORT_PRODUCT_VERSION="7"

bash-4.2#

This gives you a great option for enabling CentOS (or RHEL) based images on IBM Z. The identification above is technically very sane, since some projects check the distribution, and for some reason do not know ClefOS, but know CentOS.

Next Step: Alpine is multi-arch

As of today, the multi-arch manifest of alpine points to several architectures, including s390x. This means, you can now re-use all the Dockerfiles saying "FROM alpine" without changes (no "s390x/"). Or, of course, things like "docker run -ti alpine sh" work without an s390x/.

Docker Official Images Go Multi-Arch

Starting today, all Docker official images (on Docker Hub and soon easily identifiable on Docker Store) are multi-arch images. Official images are credibly curated images that are maintained by Docker, the Docker community or the projects behind individual images.

That does not mean that all these images are available for s390x yet, but the infrastructure is in place to several architectures into official images, i.e. all official images are manifest lists. An earlier post explained multi-arch images and how to use it.

At this time, quite some official images are not just multi-arch enabled, but also carry s390x binaries.

Another Base Image Option: Alpine for s390x

Alpine Linux has announced their new 3.6 release which includes s390x support. Alpine is a minimal Linux distro. Contrary to other distributions, it uses musl as runtime library (not glibc), helping in downsizing images.

A Docker image named s390x/alpine is available at Docker Hub and while being a fully functional base, it is just 5 MB (!) in size:

s390x/ubuntu:16.04 on Docker Hub

With https://hub.docker.com/r/s390x/ubuntu/, the first Ubuntu 16.04 image just appeared on DockerHub

Blockchain in Containers

Neale Ferguson from Sine Nomine Associates recently pushed an interesting container image on Docker Hub: brunswickheads/openchain-peer provides a blockchain environment based on openblockchain (IBM's view and one of the efforts for hyperledger). https://hub.docker.com/r/brunswickheads/openchain-peer/ comes with a description how to use it.