Linux

Open vSwitch is a software switch responsible for providing network connectivity to virtual machines or containers. Since it is programmable, it brings a challenge to understand what is going on in the network. Open vSwitch (OVS) is an OpenFlow virtual switch, so before talking about OVS itself, it is necessary to introduce OpenFlow a bit. OpenFlow is an open standard protocol that allows separation of the packet forwarding (data plane) from the high level routing decisions (control plane). The control...

Developers have a lot of choices when deciding how to start using OpenShift and Kubernetes locally --- without going through a native OS installation. We all need to have a development environment as close as possible to production (to prevent defects caused by environmental differences), but ideally we need to do this without spending a lot of time to setup and a lot of computational resources (cpu, memory and disk space). This post will present four alternatives to create a...

This article describes how an administrator can migrate Red Hat Enterprise Linux 5 or Red Hat Enterprise Linux 6 to Red Hat Enterprise Linux 7 with the help of the Preupgrade Assistant. The Preupgrade Assistant is a tool which assesses your running system for anything that might adversely affect the success of your migration. As Red Hat Enterprise Linux 5 will have only extended update support after March 2017, administrators will find a tool like that useful to help them...

P/Invoke(Platform Invocation Service) is one of the features of CLI (Common Language Interface) on .NET Framework. P/Invoke enables managed code to call a native function in DLL (Dynamic Link Library). It's a powerful tool for .NET Framework to execute existing C-style functions easily. .NET Core also has a P/Invoke feature and it means we can call a native function in .so file (Linux) and . file (Max OSX). I will show you the short example P/Invoke in .NET Core on...

The last 4-5 years have seen the debut of many new software products specifically targeting both infrastructure services and IT automation. The consumerization of IT has caused its architects to take a fresh look at their existing, often times monolithic apps and IT infrastructure and asking: Can we do better? How do I keep IT relevant? How do I keep track of all these VMs and data? How do I scale out my IT environment without a huge budget increase...

Over the last couple of weeks, I've been working on some Red Hat JBoss BPM Suite workshop material. One part of the workshop is a four-hour lab that guides the attendees through the development of JBoss BPM Suite 6.x processes, rules and applications (note that this workshop is available to our customers, please contact your Red Hat account manager or local Red Hat sales representative for more information), but I'm going to be sharing part of the story with you...

Being able to edit your C# (or F# for that matter) code on your Linux VM from Visual Studio in Windows is pretty great. As a Windows developer, you're able to work in an environment you know and trust while still being able to experiment -- and hopefully produce production code -- in Linux, where you may not be quite up to speed. Yet. Visual Studio, that familiar, productive and helpful IDE, is at your fingertips even though your code...

In the process of writing my posts ( #1 and #2) on . NET Core and RHEL, it was made clear to me by several friends that I had neglected to use the de facto standard for continuous integration on Linux, Jenkins. Always happy to try out new (to me) tools, I settled in for what I was assured would be a simple configuration to test out my previous work in this bastion of automation. What is Jenkins? The first...

Note: This post is from 2016. For current instructions, reference the documentation. https://docs.ansible.com/ansible/latest/index.html https://docs.ansible.com/ansible-tower/ With DevOps taking hold in businesses ranging from small design agencies to large enterprises, there has been a real push to automate deployments and make them consistent. As part of this, maintaining configuration as code and utilizing a version control system such as Git or Subversion to house it is becoming more prominent. Tools like Puppet and Chef have been around for a number of years...

From a developer’s perspective, “incident management” can be a pretty ambiguous term. While the first thing that comes to mind is receiving and responding to alerts, most IT professionals know it is so much more than that. Effective incident management starts with data collection and continues through alerting, escalation, collaboration, and resolution. At the server level, the most important pieces of incident management are infrastructure monitoring and log management, the vast majority of which are easily configurable on a Red...

Around this time last year, Fedora 22 brought a major update for anyone working under the Fedora hood -- Yum was deprecated and replaced by DNF. It brings some significant changes: Faster, more mathematically correct method for solving dependency resolution A “clean”, well documented Python API with C bindings & Python 3 support Isn’t this a Release by Another Name? No, DNF marks a shift, and not just a fork to Python 3, C support and cleaner docs. The move...

The sheer number of tasks involved in building out automation infrastructure for a new organization never ceases to amaze me. One of the most often overlooked groups of tasks, however, is security. Though I am in no way a security expert, I know there are some basic steps we should take to protect ourselves and our precious systems. I also know that not everyone who administers RHEL systems has an extensive background working with Linux. If, like me, you’re normally...

You obviously know what a LAMP stack is if you’ve managed to find your way here, but for those who may be unsure, the key is in the name (L)inux (A)pache (M)ariaDB (P)HP—a term that has become synonymous around the globe for building a basic web server with database and PHP functionality. There are a myriad of web applications, ranging from Wordpress to Joomla to Magento that all use this setup, and if you know how to get it up...

Wait... what? I was involved in diagnosing a production system performance problem: a web application serving thousands of interactive users was acting up. Symptoms included significant time running kernel code on behalf of the application (unexpectedly), and at those times substantial delays were observed by end users. As someone with a systems programming background, I figured I had a decent shot at figuring this one out. Naively I reached for strace(1), the system call and signal tracer, to provide insights...

The charter of Open Innovation Labs is to help our customers accelerate application development and realize the latest advancements in software delivery, by providing skills, mentoring, and tools. Some of the challenges I frequently hear from customers are those around Platform as a Service (PaaS) environment provisioning and configuration. This article is first in the series of articles that guide you through installation configuration and usage of the Red Hat OpenShift Container Platform (OCP) on Amazon Web Services (AWS). This...

Red Hat Software Collections can make your life as a programmer or admin immensely easier. Like death, taxes and zombies, dealing with different versions of software is something you just can't avoid. It's a nasty but necessary fact of life. Traditionally, when developers and system admins grapple with this issue, they have to sacrifice something. If you want to run the latest and greatest version of a web app, it might not support users with outdated browsers. If you install...

Editor's Note: If you have a Linux system that runs KVM and would like to try Red Hat Enterprise Linux on KVM, follow our KVM Get started guide, https://developers.redhat.com/products/rhel/getting-started The kernel-based Virtual Machine (KVM) is a virtualization infrastructure many have become familiar with throughout the industry. This article will guide you through getting a basic KVM hypervisor up and running and ready for use. In order to fully utilize the KVM, you will need a CPU that has virtualization extensions...

Situation: You’re a great software developer and a fearless leader. Your CEO bursts into your cubicle and he is giving you vast amounts of investment capital, no data center, and limited staff. Your task: build a multi-region, highly available presence in AWS (or your favorite cloud provider) that can be maintained by minimal man-power. Your multi-tier Java EE app is almost ready. You are going to be required to create, maintain, and monitor a large amount of servers, RDS instances...

Service Bus is, according to Microsoft, “...a generic, cloud-based messaging system for connecting just about anything.” Most commonly used as an Azure service, it can be an excellent tool for managing non-critical workloads within an application and offers the benefit of being AMQP compatible when compared to Amazon’s SQS. Connecting to Service Bus (SB) on Windows is simple, but will the new .NET Core (DNX) platform be capable of the task? Library Adventures As of the writing of this post...

As far as automated configuration management tools go, Ansible is “the new hotness” on the market. I admit, I am pretty new to Ansible. Until recently, the majority of my configuration management experience has been rooted solely in Puppet. Tack onto that my recent foray back into the world of Red Hat and I have a lot to learn, starting with getting Ansible installed and running on RHEL. There are two ways to install Ansible—via yum, or directly from source...

The Red Hat Developer Program was introduced to make it easier for any developer to create quality software. The program began with great developer tools and content provided through our developers.redhat.com website, which allows developers to download and use our enterprise products for development purposes through a free membership. This enables you to develop, prototype, test, and demo your software on the enterprise products that can be trusted to run the most demanding of enterprise production environments. Here are the...

In the first part of my series on Software Collections (SCL), I gave general information and listed the three steps needed to get started with SCL for a number of languages. This post covers the steps for PostgreSQL and MongoDB. Enable the SCL repository The first step is to enable the SCL software repository if you haven't already done so. As the root user run: # subscription-manager repos --enable rhel-server-rhscl-7-rpms Now onto installing the database software. PostgreSQL PostgreSQL is a...

Microservices are standing at the " Peak of Inflated Expectations". It's immeasurable the number of developers and companies that want to bring in this new development paradigm and don't know what challenges they will face. Of course, the challenges and the reality of an Enterprise company that has been producing software for the last 10 or 20 years is totally different from the start-up company that just released its first software some months ago. Before adopting microservices as an architectural...