Flexible Images or Using S2I for Image Configuration

Container images usually come with pre-defined tools or services with minimal or limited possibilities of further configuration. This brought us into a way of thinking of how to provide images that contain reasonable default settings but are, at the same time, easy to extend. And to make it more fun, this would be possible to achieve both on a single Linux host and in an orchestrated OpenShift environment.

Source-to-image (S2I) has been introduced three years ago to allow developers to build containerized applications by simply providing source code as an input. So why couldn’t we use it to make configuration files as an input instead? We can, of course!

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ARM TechCon 2017 – Embedded, IoT, Networking, and more…

Arm TechCon 2017 – Embedded, IoT, Networking and no Server focus

Last month was Arm TechCon, the annual developer conference showcasing offerings from Arm and its partners. Arm laid out its vision and strategy to achieving even greater integration in its processors and circumventing the slowing Moore’s law. As always, there was a bevy of new product announcements but overall, the show seemed to lack the energy of the last few years and especially the excitement of last year after Arm was acquired by Softbank. For example, there was no big vision keynote like the one last year from Masayoshi Son (Chairman & CEO of Softbank) who had talked of IoT enabling a Cambrian Explosion (which enabled thousands of new species on Earth), leading to 1 trillion IoT devices in 20 years.

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PHP Configuration Tips

RHEL 7 provides the Apache HTTP Server version 2.4 and PHP version 5.4.

The most common configuration for Apache httpd and PHP uses, but this has some limitations and drawbacks:

  • a single PHP version of mod_php can be used
  • mod_php run in the httpd process, without any isolation
  • mod_phpis only supported for the prefork MPM

This article will explain how to configure Apache httpd to delegate PHP scripts execution to a backend using the FastCGI protocol, how to use a more recent PHP version, how to run multiple PHP versions, and how to improve Apache httpd performance.

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Entropy in RHEL based cloud instances

According to Wikipedia, entropy is the randomness collected by an operating system or application for use in cryptography or other uses that require random data.

Entropy is often overlooked, misconfigured or forgotten and it can originate in sporadic errors whether it can be timeouts, refused connections, etc. Such errors are difficult to debug as the errors happen only when there is not enough entropy available.

This article tries to explain briefly how to check if this can be a problem in a RHEL system and how to fix it.

NOTE: This article is meant to provide some helpful hints about entropy. It is not meant to be exhaustive or definitive. There are hundreds of information sources on the Internet such as KCS articles; https://access.redhat.com/articles/221583 and https://access.redhat.com/solutions/19866 where this article is based. Check the bibliography section for more information.

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How to enable/disable repository using Subscription Manager or Yum-Utils

This blog is to resolve the following issues/answering the following questions.

  1. How to enable a repository using the Red Hat Subscription Manager/yum?
  2. Need to access a repository using the Red Hat Subscription Manager/yum?
  3. How to disable a repository using the Red Hat Subscription Manager/yum?
  4. How to subscribe a child channel using the Red Hat Subscription Manager/yum?

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