Podman

Rootless containers with Podman: The basics

Rootless containers with Podman: The basics

As a developer, you have probably heard a lot about containers. A container is a unit of software that provides a packaging mechanism that abstracts the code and all of its dependencies to make application builds fast and reliable. An easy way to experiment with containers is with the Pod Manager tool (Podman), which is a daemonless, open source, Linux-native tool that provides a command-line interface (CLI) similar to the docker container engine.

In this article, I will explain the benefits of using containers and Podman, introduce rootless containers and why they are important, and then show you how to use rootless containers with Podman with an example. Before we dive into the implementation, let’s review the basics.

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Introducing the Red Hat build of the OpenJDK Universal Base Images—now in Red Hat Enterprise Linux 8.2

Introducing the Red Hat build of the OpenJDK Universal Base Images—now in Red Hat Enterprise Linux 8.2

With the recent release of Red Hat Enterprise Linux 8.2, we also added the first Red Hat build of OpenJDK Universal Base Images. These General Availability (GA) images for OpenJDK 8 and OpenJDK 11 set a new baseline for anyone who wants to develop Java applications that run inside containers in a secure, stable, and tested manner.

In this article, we introduce the new OpenJDK Universal Base Images and explain their benefits for Java developers. Before we do that, let’s quickly review what we know about UBIs in general.

About Universal Base Images

Red Hat Universal Base Images (UBIs) are:

OCI-compliant container base operating system images with complementary runtime languages and packages that are freely redistributable. Like previous base images, they are built from portions of Red Hat Enterprise Linux (RHEL). UBI images can be obtained from the Red Hat container catalog and be built and deployed anywhere.

In other words, UBIs help application developers reach the secure, stable, and portable world of containers. These images are accessible using well-known tools like Podman/Buildah and Docker. Red Hat Universal Base Images also allow users to build and distribute their own applications on top of enterprise-quality bits that are supportable on Red Hat OpenShift and Red Hat Enterprise Linux.

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How to customize Fedora CoreOS for dedicated workloads with OSTree

How to customize Fedora CoreOS for dedicated workloads with OSTree

In part one of this series, I introduced Fedora CoreOS (and Red Hat CoreOS) and explained why its immutable and atomic nature is important for running containers. I then walked you through getting Fedora CoreOS, creating an Ignition file, booting Fedora CoreOS, logging in, and running a test container. In this article, I will walk you through customizing Fedora CoreOS and making use of its immutable and atomic nature.

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Building freely distributed containers with Podman and Red Hat UBI

Building freely distributed containers with Podman and Red Hat UBI

DevNation tech talks are hosted by the Red Hat technologists who create our products. These sessions include real solutions and code and sample projects to help you get started. In this talk, you’ll learn about building containers with Podman and Red Hat Universal Base Image (UBI) from Scott McCarty and Burr Sutter.

We will cover how to build and run containers based on UBI using just your regular user account—no daemon, no root, no fuss. Finally, we will order the de-resolution of all of our containers with a really cool command. After this talk, you will have new tools at the ready to help you find, run, build, and share container images.

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Verifying signatures of Red Hat container images

Verifying signatures of Red Hat container images

Security-conscious organizations are accustomed to using digital signatures to validate application content from the Internet. A common example is RPM package signing. Red Hat Enterprise Linux (RHEL) validates signatures of RPM packages by default.

In the container world, a similar paradigm should be adhered to. In fact, all container images from Red Hat have been digitally signed and have been for several years. Many users are not aware of this because early container tooling was not designed to support digital signatures.

In this article, I’ll demonstrate how to configure a container engine to validate signatures of container images from the Red Hat registries for increased security of your containerized applications.

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Working with Red Hat Enterprise Linux Universal Base Images (UBI)

Working with Red Hat Enterprise Linux Universal Base Images (UBI)

If you’re like me—a developer who works with customers who rely on the tried-and-true Red Hat Enterprise Linux (RHEL), works with containerized applications, and also prefers to work with Fedora Linux as their desktop operating system—you’re excited by the announcement of the Universal Base Images (UBI). This article shows how UBI actually works, by building the container image for a simple PHP application.

With UBI, you can build and redistribute container images based on Red Hat Enterprise Linux without requiring a Red Hat subscription. Users of UBI-based container images do not need Red Hat subscriptions. No more extra work creating CentOS-based container images for your community projects or for your customers that prefer self-support.

I tested all these steps on my personal Fedora 29 system, and they should work on any Linux distribution. I am also a big fan of the new container tools such as Podman, which should be available to your favorite Linux distribution. If you are working on a Windows or MacOS system, you can replace the Podman commands with Docker.

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Red Hat Enterprise Linux 8 now generally available

Red Hat Enterprise Linux 8 now generally available

I think Red Hat Enterprise Linux 8 is the most developer-friendly Red Hat Enterprise Linux that we’ve delivered, and I hope you agree. Let’s get down to business, or rather coding, so you can see for yourself. You can read the Red Hat corporate press release.

For this article, I’ll quickly recap Red Hat Enterprise Linux 8 features (architecture, containers), introduce the very new and cool Red Hat Universal Base Image (UBI), and provide a handy list of developer resources to get you started on Red Hat Enterprise Linux 8.

TL;DR

Download RHEL 8 now

Download RHEL 8 image

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Podman basics cheat sheet

Podman basics cheat sheet

Here and elsewhere, we get a lot of questions about post-Docker container tools in Red Hat Enterprise Linux 7.6 and Red Hat Enterprise Linux 8 beta. Tools like podman, buildah, and skopeo enable you to create and manage rootless containers, which are containers that don’t require root access to be built and deployed. To help you master the basics, we’re happy to offer a new podman basics cheat sheet.

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How to run systemd in a container

How to run systemd in a container

I have been talking about systemd in a container for a long time. Way back in 2014, I wrote “Running systemd within a Docker Container.” And, a couple of years later, I wrote another article, “Running systemd in a non-privileged container,” explaining how things hadn’t gotten much better. In that article, I stated, “Sadly, two years later if you google Docker systemd, this is still the article people see—it’s time for an update.” I also linked to a talk about how upstream Docker and upstream systemd would not compromise. In this article, I’ll look at the progress that’s been made and how Podman can help.

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