Infrastructure

Red Hat Enterprise Linux 8 Image Builder: Building custom system images

Red Hat Enterprise Linux 8 Image Builder: Building custom system images

Red Hat Enterprise Linux 8 Beta ships a new tool, called Image Builder, that allows you to create custom Red Hat Enterprise Linux system images in a variety of formats. These include compatibility with major cloud providers and virtualization technologies available in the market. As a result, it enables you to quickly spin up new Red Hat Enterprise Linux (RHEL) systems in different platforms, according to your requirements. At this time, Image Builder is available as a Technology Preview Feature.

In this article, we’ll show how to set up Image Builder in Red Hat Enterprise Linux 8 Beta and create a couple of images to test its capabilities. To follow this tutorial, you will need two virtual machines running Red Hat Enterprise Linux 8 Beta. We’ll not cover Red Hat Enterprise Linux 8 Beta installation in this post. For more information, take a look at Get RHEL8 Beta.

Continue reading “Red Hat Enterprise Linux 8 Image Builder: Building custom system images”

Share
A platform interface for the GNU C Library

A platform interface for the GNU C Library

Application developers continue to need newer versions of libraries, including core runtimes like GNU C Library (glibc), for their applications. In this article, I’ll look at some issues related to upgrading glibc in an operating system (OS) distribution, and I also encourage you to read Florian Weimer’s excellent blog post on the topic.

The problem

Deciding between a library rebase or continued backporting of commits involves a complex set of risks and rewards. For some customers and users, it is important not to rebase the library (ensuring the lowest risk of impact by change); but for others, the rebase brings valuable bug fixes (lowest risk of impact from known issues). In other cases, the newer library may perform better, even if the interfaces haven’t changed, because it can take advantage of newer hardware or a newer Linux kernel (performance advantage to first mover).

There is no way to simultaneously satisfy all the requirements of slow-moving versus fast-moving development. The recent work in Fedora Modularity is aimed at solving the root of this problem, but there is a limit to this work. The further down the stack you go, the harder the problem becomes. The potential for breakage further up the stack increases. You can’t always arbitrarily change a component’s installed version without consequences, either at build time or at runtime.

Continue reading “A platform interface for the GNU C Library”

Share
An introduction to Linux virtual interfaces: Tunnels

An introduction to Linux virtual interfaces: Tunnels

Linux has supported many kinds of tunnels, but new users may be confused by their differences and unsure which one is best suited for a given use case. In this article, I will give a brief introduction for commonly used tunnel interfaces in the Linux kernel. There is no code analysis, only a brief introduction to the interfaces and their usage on Linux. Anyone with a network background might be interested in this information. A list of tunnel interfaces, as well as help on specific tunnel configuration, can be obtained by issuing the iproute2 command ip link help.

Continue reading “An introduction to Linux virtual interfaces: Tunnels”

Share
Using .NET PInvoke for Linux system functions

Using .NET PInvoke for Linux system functions

If you’ve developed Windows applications with .NET, you may have found yourself in a situation where the framework did not provide the APIs you needed. When that happens, you first need to identify the system APIs and then make them available using PInvoke. A website like pinvoke.net provides copy-and-pasteable code snippets for many Win32 API functions.

.NET Platform Invoke (PInvoke) makes it easy to consume native libraries. In this article, we’ll take a look at using PInvoke for Linux system functions.

Continue reading “Using .NET PInvoke for Linux system functions”

Share
RPM packaging: A simplified guide to creating your first RPM

RPM packaging: A simplified guide to creating your first RPM

The concept of RPM packaging can be overwhelming for first-timers because of the impression a steep learning curve is involved. In this article, I will demonstrate that building an RPM with minimal knowledge and experience is possible. Note that this article is meant as a starting point, not a complete guide to RPM packaging.

Continue reading “RPM packaging: A simplified guide to creating your first RPM”

Share
Set up JDK Mission Control with Red Hat Build of OpenJDK

Set up JDK Mission Control with Red Hat Build of OpenJDK

JDK Mission Control is now the newest member of the Red Hat Software Collections (RHSCL). JDK Mission Control is a powerful profiler for HotSpot Java virtual machines (JVMs) and has an advanced set of tools that enable efficient and detailed analysis of the extensive data collected by JDK Flight Recorder. The toolchain enables developers and administrators to collect and analyze data from Java applications running locally or deployed in production environments using OpenJDK 11.

In this article, I will go through a primary example of setting up JDK Mission Control. For Linux, JDK Mission Control is part of the RHSCL and, for Windows, it is available as part of the OpenJDK zip distribution on the Red Hat Customer Portal.  For Linux, these instructions assume that Red Hat Build of OpenJDK 11 is already installed. I will show how to set up the system to install software from RHSCL, which provides the latest development technologies for Red Hat Enterprise Linux. Then, I will install the JDK Mission Control and run a simple sample application. The whole tutorial should take fewer than 10 minutes to complete.

Continue reading “Set up JDK Mission Control with Red Hat Build of OpenJDK”

Share
How to set up a LAMP stack quickly on Red Hat Enterprise Linux 8 Beta

How to set up a LAMP stack quickly on Red Hat Enterprise Linux 8 Beta

Have you tried the Red Hat Enterprise Linux 8 (RHEL8) Beta yet? Read on to learn how to stand up a LAMP stack on top of RHEL8 Beta quickly, and play around with new features built into the operating system.

A LAMP stack is made up out of four main components, and some glue. The first main component in a LAMP stack is Linux. In my example, I’m using Red Hat Enterprise Linux 8 Beta for that, which gives me a secure operating system, a modern programming environment, and user-friendly set of tools to control it.

Continue reading “How to set up a LAMP stack quickly on Red Hat Enterprise Linux 8 Beta”

Share
Changes made to the Libabigail ABI change analysis framework in 2018

Changes made to the Libabigail ABI change analysis framework in 2018

This article is for people interested in the long-term maintenance of software systems that expose application binary interfaces (a.k.a. ABIs) to other systems. That long-term maintenance involves detecting and analyzing inevitable changes in the ABIs and assessing whether these changes allow the maintained systems to stay compatible with the components with which they interact.

In this article, I describe what happened to the ABI change analysis framework that I worked on during 2018: the Abigail library (Libabigail) and its associated set of tools. The goal is not to list the myriad changes that happened throughout releases 1.2, 1.3, 1.4, and 1.5 that occurred during that year, but I will walk you through the main changes that happened and put them in perspective.

Continue reading “Changes made to the Libabigail ABI change analysis framework in 2018”

Share
Introduction to using libFuzzer with llvm-toolset

Introduction to using libFuzzer with llvm-toolset

“Fuzzing” an application is a great way to find bugs that may be missed by other testing methods. Fuzzers test programs by generating random string inputs and feeding them into an application. Any program that accepts arbitrary inputs from its users is a good candidate for fuzzing. This includes compilers, interpreters, web applications, JSON or YAML parsers, and many more types of programs.

libFuzzer is a library to assist with the fuzzing of applications and libraries. It is integrated into the Clang C compiler and can be enabled for your application with the addition of a compile flag and by adding a fuzzing target to your code. libFuzzer has been used successfully to find bugs in many programs, and in this article, I will show how you can integrate libFuzzer into your own applications.

Continue reading “Introduction to using libFuzzer with llvm-toolset”

Share
How to install GCC 8 and Clang/LLVM 6 on Red Hat Enterprise Linux 7

How to install GCC 8 and Clang/LLVM 6 on Red Hat Enterprise Linux 7

There has been a lot of work to improve C/C++ compilers in recent years. A number of articles have been posted by Red Hat engineers working on the compilers themselves covering usability improvements, features to detect possible bugs, and security issues in your code.

Red Hat Enterprise Linux 8 Beta ships with GCC 8 as the default compiler. This article shows you how to install GCC 8 as well as Clang/LLVM 6 on Red Hat Enterprise Linux 7. You’ll be able to use the same updated (and supported) compilers from Red Hat on both RHEL 7 and 8.

If you want your default gcc to always be GCC 8, or you want clang to always be in your path, this article shows how to permanently enable a software collection by adding it to the profile (dot files) for your user account. A number of common questions about software collections are also answered.

Continue reading “How to install GCC 8 and Clang/LLVM 6 on Red Hat Enterprise Linux 7”

Share