Docker Archives - Red Hat Developer

Introduction to Eclipse JKube: Java tooling for Kubernetes and Red Hat OpenShift

By Rohan Kumar January 28, 2020February 11, 2020

We as Java developers are often busy working on our applications by optimizing application memory, speed, etc. In recent years, encapsulating our applications into lightweight, independent units called containers has become quite a trend, and almost every enterprise is trying to shift its infrastructure onto container technologies like Docker and Kubernetes.

Kubernetes is an open source system for automating deployment, scaling, and management of containerized applications, but it has a steep learning curve, and an application developer with no background in DevOps can find this system a bit overwhelming. In this article, I will talk about tools that can help when deploying your Maven applications to Kubernetes/Red Hat OpenShift.

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Using Kubernetes ConfigMaps to define your Quarkus application’s properties

By Sébastien Blanc January 23, 2020January 22, 2020

So, you wrote your Quarkus application, and now you want to deploy it to a Kubernetes cluster. Good news: Deploying a Quarkus application to a Kubernetes cluster is easy. Before you do this, though, you need to straighten out your application’s properties. After all, your app probably has to connect with a database, call other services, and so on. These settings are already defined in your application.properties file, but the values match the ones for your local environment and won’t work once deployed onto your cluster.

So, how do you easily solve this problem? Let’s walk through an example.

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Best practices for running Buildah in a container

By Daniel Walsh August 14, 2019October 17, 2019

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.

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

By Fernando Lozano May 31, 2019September 23, 2019

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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2 tips to make your C++ projects compile 3 times faster

By Konrad Kleine May 15, 2019September 3, 2019

In this article, I will demonstrate how to speed up your compilation times by distributing compilation load using a distcc server container. Specifically, I’ll show how to set up and use containers running a distcc server to distribute the compilation load over a heterogeneous cluster of nodes (development laptop, old desktop PC, and a Mac). To improve the speed of recompilation, I will use ccache.

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Podman basics cheat sheet

By Doug Tidwell April 25, 2019April 24, 2019

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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Creating and deploying a Java 8 runtime container image

By Syed M Shaaf February 26, 2019September 3, 2019

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.

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Podman and Buildah for Docker users

By William Henry February 21, 2019October 10, 2019

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.

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Managing containerized system services with Podman

By Alessandro Arrichiello November 29, 2018September 3, 2019

In this article, I discuss containers, but look at them from another angle. We usually refer to containers as the best technology for developing new cloud-native applications and orchestrating them with something like Kubernetes. Looking back at the origins of containers, we’ve mostly forgotten that containers were born for simplifying application distribution on standalone systems.

In this article, we’ll talk about the use of containers as the perfect medium for installing applications and services on a Red Hat Enterprise Linux (RHEL) system. Using containers doesn’t have to be complicated, I’ll show how to run MariaDB, Apache HTTPD, and WordPress in containers, while managing those containers like any other service, through systemd and systemctl.

Additionally, we’ll explore Podman, which Red Hat has developed jointly with the Fedora community. If you don’t know what Podman is yet, see my previous article, Intro to Podman (Red Hat Enterprise Linux 7.6) and Tom Sweeney’s Containers without daemons: Podman and Buildah available in RHEL 7.6 and RHEL 8 Beta.

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Intro to Podman (Red Hat Enterprise Linux 7.6 Beta)

By Alessandro Arrichiello August 29, 2018October 18, 2018

Red Hat Enterprise Linux (RHEL) 7.6 Beta was released a few days ago and one of the first new features I noticed is Podman. Podman complements Buildah and Skopeo by offering an experience similar to the Docker command line: allowing users to run standalone (non-orchestrated) containers. And Podman doesn’t require a daemon to run containers and pods, so we can easily say goodbye to big fat daemons.

Podman implements almost all the Docker CLI commands (apart from the ones related to Docker Swarm, of course). For container orchestration, I suggest you take a look at Kubernetes and Red Hat OpenShift.

Podman consists of just a single command to run on the command line. There are no daemons in the background doing stuff, and this means that Podman can be integrated into system services through systemd.

We’ll cover some real examples that show how easy it can be to transition from the Docker CLI to Podman.

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