Docker

Kubernetes is a great tool for container orchestration on a server cluster. It makes it easy to deploy lots of containers in a resource-efficient way using a simple interface. But one thing that is not easy to do with Kubernetes is to deploy it locally. Kubernetes is designed to run on an actual cluster, which means using it only on a single computer is tough. I know. You're probably wondering why you'd want to use Kubernetes locally in the first...

I'm guessing if you've done enough repeated builds on OpenShift, using Maven, that you are probably aware of the " download the internet " phenomenon that plagues build times. You start a build, expecting all those Maven dependencies you downloaded for your last build to be re-used, but quickly see your network traffic ramp up while the same 100MB of jars are downloaded again and again. Even builds of a few minutes tend to grind on me, frustrate me as...

Cloud based technology offers the ability to build, deploy and scale applications with ease; however, deploying to the cloud is only half of the battle. How cloud applications are monitored becomes a paramount concern with operations teams. When issues arise, teams and their monitoring systems must be able to detect, react, and rectify the situation. CPU, system memory, and disk space are three common indicators used to monitor applications, and are typically reported by the operating system. However, for Java...

A recent blog post, 10 things to avoid in docker containers , describes ten scenarios you should avoid when dealing with docker containers. However, recommendation # 3 - Don’t create large images and the sentence "Don’t install unnecessary packages or run “updates” ( yum update ) that download files to a new image layer" has generated quite a few questions. Some of you are wondering how a simple yum update can create a large image. In an attempt to clarify...

So you finally surrendered to containers and discovered that they solve a lot of problems and have a lot of advantages : First: Containers are immutable - The OS, library versions, configurations, folders, and application are all wrapped inside the container. You guarantee that the same image that was tested in QA will reach the production environment with the same behaviour. Second: Containers are lightweight - The memory footprint of a container is small. Instead of hundreds or thousands of...

2015 is coming to a close and it’s always fun to reflect on all that has changed, grown, and news that almost make you wonder if pigs can now fly. Our team has greatly expanded, the community is growing, we are now accepting content contributors from around the world...so much to pick from. As you can tell it’s been a busy year and here are just some of top highlights. Here we go and in no particular order: 1) A...

Red Hat Software Collections (RHSCL) 2.0 brings Perl 5.20 as a Docker image. This allows you to deploy Perl applications easily. The basic idea is to combine your application code from Git tree and Red Hat's rhscl/perl-520-rhel7 base image into an application image that will run your application in mod_perl environment. Your application can either be a simple Common Gateway Interface (CGI) script or a full-fledged Perl Web Server Gateway Interface (PSGI) application. Following this step-by-step procedure will show you...

New RHSCL-based Docker images that are now in beta let you easily build your own application containers even without writing any Dockerfiles. Here is an example of a Ruby on Rails application built with the Ruby 2.2 image using the PostgreSQL 9.4 image as a database backend. For building the application image we will use a tool called source-to-image (s2i, formally sti) which is a program that can build your application image on top of s2i images. For example the...

“As a part of the Red Hat Software Collections offering, Red Hat provides a number of container images , which are based on the corresponding Software Collections. These include application, daemon, and database images. The provided images, currently available in the Beta version” (for more information see https://access.redhat.com/articles/1752723 ) Red Hat Software Collections allows you to run newer versions of software on a stable Red Hat Enterprise Linux. These new images combine this feature with the benefits of containers. In...

I'm very happy to announce that Docker images based on collections from Red Hat Software Collections (RHSCL) 2.0 are in beta testing. The images are available from the Red Hat Container Registry , and we've got the set of collections for language, databases and web servers covered - a complete list is below. If you've not tried out the Docker package from RHEL7 Extras, you need to enable the Extras channel, install the docker page, and start the docker service...

Background I’ve been working with the CTO of a online video game company to develop a container architecture for his business. The goal is to simplify the deployment of new applications as well as make it easier to go back and change code on older applications. The desired state is environmental parity across the infrastructure -- this will simplify the assignment of work on different applications to different developers. From developer laptops to production servers, the code will just work...

So here's are deal: We've created what we're calling "PaaS-Containers" in our IT production environment. It consists of core technologies like RHEL Atomic Host, Kubernetes, and Docker along with supporting CI/CD components like Jenkins together as part of an offering that supports the end-to-end automated deployments of applications from a code-commit event through automated testing and roll-out through multiple environments (dev, QA, stage, prod). Oh, did I mention that it's also integrated with our enterprise logging and monitoring as well...

Imagine this: deploy an application from code-commit to qa, validate through automated testing, and then push the same image into production with no manual intervention, no outage, no configuration changes, and with full audibility through change records. A month-and-a-half ago, we formed a tiger team and gave them less than 90 days to do it. How? Build an end-to-end CI/CD environment leveraging RHEL Atomic 7.1 as the core platform and integrating with key technologies like git, Jenkins, packer.io , in...

This past few weeks I've been working on making remote debugging in GDB easier to use. What's remote debugging? It's where you run GDB on one machine and the program being debugged on another. To do this you need something to allow GDB to control the program being debugged, and that something is called the remote stub. GDB ships with a remote stub called gdbserver, but other remote stubs exist. You can write them into your own program too, which...

Containerizing things is particularly popular these days. Today we'll talk about the idioms we can use for containerization, and specifically play with apache spark and cassandra in our use case for creating easily deployed, immutable microservices. Note: This post is done using centos7 as a base for the containers, but these same recipes will apply with RHEL and Fedora base images. There are a few different ways to build a container. For example, for beginners, you can build a container...

This blog is a continuation of " Creating custom Atomic trees, images, and installers - Part 1 ." In part one, we learned how to compose our own atomic trees and consume them in a guest. In part two, we will learn how to create our own disk images and installer media. Creating custom disk images As mentioned in the previous blog, the subcommand imagefactory can be used to create disk images. As of this writing, the imagefactory subcommand can...

If one thing survived all the New Year parties, it is Docker. It was hot at the end of 2014 and it looks like it is getting even hotter in 2015. And Red Hat is one of the key drivers behind the adoption of this amazing container technology. This is a short summary blog post about a bunch of resources to get you started with Java EE, WildFly and Microservices on Docker mostly collecting resources and information from the JBoss...

Here are five most read articles on developerblog.redhat.com in 2014 - be sure to read them: A Practical Introduction to Docker Containers, by Scott McCarty - 25,000 views Comprehensive Overview of Storage Scalability in Docker, by Jeremy Eder - 19,000 Why Python 4.0 won’t be like Python 3.0, by Nick Coghlan - 14,000 Red Hat Enterprise Linux 7 now Generally Available, 13,000 GCC Undefined Behavior Sanitizer – ubsan, by Marek Polacek, 10,000

Use cases In Red Hat Enterprise Linux we support a variety of different versions of PHP. Sometimes users find they need to run a legacy application, requiring an older version of PHP, on a newer version of RHEL. Developers may want to develop an application on their Fedora Workstation and deploy it on a RHEL server or ensure it will be compatible with all available PHP versions in enterprise distributions. This example can be easily adapted for all PHP versions...

Can you believe it's December and almost 2015? Where does the time go? Last month, we shared a Thanksgiving "thank you" for open source. December holidays are commonly about giving, so Red Hat is giving you the opportunity to use containers with the new availability of Red Hat Enterprise Linux® Atomic Beta. This follows the Red Hat Summit 2014 announcement about application containers, including the upstream Project Atomic and our intent to develop a small footprint, container host based on...

We recently announced that we've made available a set of Dockerfiles for Red Hat Software Collections. We are making these available since we think they may be useful to customers looking to build more complex application containers on top of RHEL and RHSCL. We don't intend the Dockerfiles to produce useful standalone images which you'll immediately put in production - the Docker images which these create are very simple containers which give you RHEL plus the basic set of packages...

Like most programmers, I find it much easier to take some existing example of code and modify it to do what I want. Sometimes, I end up with nothing from the original source, but I still find it easier. I wonder if this is akin to writing where, I find, if you put the words down in a stream of consciousness manner, then " rewrite , rewrite , rewrite ." As such, I am really excited about the efforts from...

An interesting article as OpenShift v3 introduces Docker containers. At Crunchy Data Solutions (Crunchy)we were excited to hear the recent announcement from the OpenShift team regarding the new public Origin repo integrating the work Red Hat has been doing for over twelve months in OpenShift Origin and related projects like Docker , Kubernetes , GearD and Project Atomic . Crunchy has been working with the OpenShift team for some time and witnessed the value proposition of combining PostgreSQL , a...

Letting the containers out of containment I have written a lot about *Containing the Containers*, e.g. * Are Docker containers really secure? * and * Bringing new security features to Docker *. However, what if you want to ship a container that needs to have access to the host system or other containers? Well, let's talk about removing all the security! Safely? Packaging Model I envision a world where lots of software gets shipped in image format. In other words...