How do you install two or more RPM packages when they depend on each other?

Question:  How do you solve circular dependency problems when installing RPMs in RedHat Linux?
Problem Scenario:  For example, you keep trying to install different RPMs, but they always require a different installation.  By exhaustively going through the dependencies, you find a circle of dependencies.  This is sometimes called mutual recursion.

Root cause:  Human error.

Solution:  The way to resolve circular dependencies is with a yum localinstall command with a list of each of the RPM packages afterward.

 » Read more..

Possible Problems With Rendering PHP with Apache

Problem scenario
Your PHP code is being displayed in a raw fashion.  It is not being rendered or presented nicely as it should.  You see raw PHP text when you open a web browser and go to the .php page.  What should you do?

Solution
If the PHP page is blank (or completely white), see this posting.

How To Potentially Solve an HTTP 403 Error on An Apache Server

Problem scenario:  You are trying to access a file on a website.  But you get the 403 Forbidden error every time.  What are some different things to look for to fix this problem?

Solution:

If you do not have access to the back-end of the web server, try these:

  1. Clear the cache/history from your web browser 
  2. Clear the cookies from your web browser 
  3. If you are using wget,

 » Read more..

OpenStack Sahara Documentation

Some open source projects don’t always listen to contributors’ feedback.  We reported a couple errors that we found in OpenStack documentation to openstack.org.  Here are the errors we saw (as of 2/2/17):

#1  If you go to this link, you’ll find two “Storm EDP” links:
http://specs.openstack.org/openstack/sahara-specs/

One points to this link:  http://specs.openstack.org/openstack/sahara-specs/specs/liberty/storm-scaling.html

We see no reason why the title/header of this above page is “Storm EDP” and not “Storm Scaling.”  My attempt at a contribution was to not have two “Storm EDP” links in the first link of this post. 

 » Read more..

SaltStack Technology and Terminology

SaltStack provides for more complex configuration management than Ansible (another Python-based) configuration management tool.  Some people have criticized Salt for having too many new vocabulary words.  Like all complex technologies, they take time getting used to.  To help learn about Salt, I thought I’d provide an overview.

An SLS file is a SaltStack State file.  This file is the basis for determining the desired configuration of the client servers that are called Salt Minions. 

 » Read more..

Containerization Has Its Advantages Over Virtualization

Containers, such as Docker, communicate to each other through a shared kernel.  Guest virtual machines communicate to each other through the hypervisor or host operating system.  Containers enjoy faster communication as staying within a shared kernel allows for more rapid communication than leaving a virtual machine and going out to a hypervisor (or host operating system) to communicate with another virtual machine.  Containers allow for sequestration of processes and fewer operating systems licenses compared to having a comparable solution with virtual machines. 

 » Read more..

DevOps and ETL Quiz

Extract-Transform-Load workflows involve considerable architecture including a workflow over a network to take data from a flat file and ingest it into a database.  Automation is one way to manage the ETL support system.  DevOps Engineers commonly support database installations and configurations.  DevOps engineers commonly support continual delivery pipelines.  This automated process (involving automatic deployments) is often similar to automating an ETL process.  DevOps engineering, build and release engineering, automation development, and ETL design are all interdisciplinary fields of information technology. 

 » Read more..