DevNation Tech Talks are hosted by the Red Hat technologists who create our products. These sessions include real solutions plus code and sample projects to help you get started. In this talk, you’ll learn about using Java with containers from Markus Eisele and Burr Sutter.
Continue reading Commit to excellence: Java in containers
Go is an increasingly popular programming language, and frequently chosen for developing command-line utilities. Many tools used with Kubernetes and Red Hat OpenShift are written in Go, including the command-line interfaces (CLIs) for Tekton (
tkn), OpenShift (
oc), and Kubernetes (
kubectl). Also, developers can compile Go to a single executable for a broad range of operating systems. As a result, it’s easy to develop and desk-test applications before putting them into containers and running those containers in OpenShift.
In a meta sort of way, this is an article about a tutorial, where I show you how to build and deliver a small Go RESTful service using OpenShift Pipelines. You could just jump to the tutorial now, but I suggest reading this article first. I’ll quickly introduce the working environment for the tutorial, and I’ll explain my logic for setting up the tutorial the way that I did.
Continue reading “Build a Go application using OpenShift Pipelines”
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.
Continue reading How to customize Fedora CoreOS for dedicated workloads with OSTree
I have a problem. My daily laptop is a MacBook Pro, which is great unless you want to dual boot into Linux and develop on containers. While it is simple enough to install Red Hat CodeReady Containers, what I really needed was a way to run Buildah, Podman, and skopeo on macOS without having to water and feed a Linux VM.
Continue reading Podman for macOS (sort of)
One of the cool things about separating the container runtimes into different tools is that you can start to combine them to help secure one other.
Lots of people would like to build OCI/container images within a system like Kubernetes. Imagine you have a CI/CD system that is constantly building container images, a tool like Red Hat OpenShift/Kubernetes would be useful for distributing the load of builds. Until recently, most people were leaking the Docker socket into the container and then allowing the containers to do
docker build. As I pointed out years ago, this is one of the most dangerous things you can do. Giving people root access on the system or sudo without requiring a password is more secure than allowing access to the Docker socket.
Because of this, many people have been attempting to run Buildah within a container. We have been watching and answering questions on this for a while. We have built an example of what we think is the best way to run Buildah inside of a container and have made these container images public at quay.io/buildah.
Continue reading “Best practices for running Buildah in a container”
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.
Download RHEL 8 now
Download RHEL 8 image
Continue reading “Red Hat Enterprise Linux 8 now generally available”
This past Christmas I gave my wife a set of nesting dolls similar to Russian Matryoshka dolls. If you’re not familiar with them, they consist of a wooden doll, which opens to reveal another doll, inside which you’ll find another doll, and so on until you get to the smallest and often most ornate doll of them all. This concept got me thinking about nesting containers.
I thought I’d try building my own nesting container using Podman to create a container in which I could do Buildah development and also spin up Buildah containers and images. Once this Podman container was created, I could move it to any Linux platform that supported Podman and do development on Buildah from it. In this article, I’ll show how I set it up.
Continue reading “Build and run Buildah inside a Podman container”
A Java runtime environment should be able to run compiled source code, whereas a development kit, for example, OpenJDK, would include all the libraries/binaries to compile and run the source code. Essentially the latter is a superset of the runtime environment. More details on OpenJDK support and lifecycle can be found here.
Red Hat ships and supports container images with OpenJDK for both Java 8 and 11. More details are here. If you are using Red Hat Middleware, the s2i images shipped are also useful to deploy, for example, on Red Hat Openshift Container Platform.
Note that Red Hat only provides OpenJDK-based Java 8 and 11 images. With that said, there will certainly be situations where developers would like to create their own Java runtime images. For example, there could be reasons such as minimizing storage to run a runtime image. On the other hand, a lot of manual work around libraries such as Jolokio or Hawkular and even security parameters would need to be set up as well. If you’d prefer not to get into those details, I would recommend using the container images for OpenJDK shipped by Red Hat.
In this article we will:
- Build an image with Docker as well as Buildah.
- We will run that image with Docker as well as Podman on localhost.
- We will push our image to Quay.
- Finally, we will run our app by importing a stream into OpenShift.
This article was written for both OpenShift 3.11 and 4.0 beta. Let’s jump right into it.
Continue reading “Creating and deploying a Java 8 runtime container image”
I was asked recently on Twitter to better explain Podman and Buildah for someone familiar with Docker. Though there are many blogs and tutorials out there, which I will list later, we in the community have not centralized an explanation of how Docker users move from Docker to Podman and Buildah. Also what role does Buildah play? Is Podman deficient in some way that we need both Podman and Buildah to replace Docker?
This article answers those questions and shows how to migrate to Podman.
Continue reading “Podman and Buildah for Docker users”
Kubernetes installations can be complex with multiple runtime dependencies and runtime engines. CRI-O was created to provide a lightweight runtime for Kubernetes which adds an abstraction layer between the cluster and the runtime that allows for various OCI runtime technologies. However you still have the problem of depending on daemon(s) in your cluster for builds – I.e. if you are using the cluster for builds you still need a Docker daemon.
Enter Buildah. Buildah allows you to have a Kubernetes cluster without any Docker daemon for both runtime and builds. Excellent. But what if things go wrong? What if you want to do troubleshooting or debugging of containers in your cluster? Buildah isn’t really built for that, what you need is a client tool for working with containers and the one that comes to mind is Docker CLI – but then you’re back to using the daemon.
This is where Podman steps in. Podman allows you to do all of the Docker commands without the daemon dependency. To see examples of Podman replacing the
docker command, see Alessandro Arrichiello’s Intro to Podman and Doug Tidwell’s Podman—The next generation of Linux container tools.
Continue reading “Containers without daemons: Podman and Buildah available in RHEL 7.6 and RHEL 8”