A Technical I.T./DevOps Blog
Problem scenario
You want to buy more RAM for your desktop computer. You find it is frequently memory constrained (e.g., when you look at the Task Manager if it is running Windows or use the top utility from a Linux command prompt. What should you do?
Solution
Know the difference between DDR3 and DDR4 RAM. If you want to read an article about the difference between DDR3 and DDR4 RAM,
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Automating vSphere with VMware vCenter Orchestrator (VMware Press Technology) by Cody Bunch
Building Blocks: vSphere 6.0 and vCenter 6.0 by Tom Burge and Calvin Kohler-Katz
Cloud Computing, A Practical Approach by Toby Velte, Anthony Velte and Robert Elsenpeter
Critical VMware Mistakes You Should Avoid by Larry Loucks and Rajen Guendoo
Disaster Recovery using VMware vSphere Replication and vCenter Site Recovery Manager – Second Edition by Abhilash G B
Enterprise Java Applications Architecture on VMware by Emad Benjamin
IBM System Storage N Series With Vmware Vsphere 5 by IBM Redbooks
It Architect: Foundation in the Art of Infrastructure Design: A Practical Guide for It Architects by Vcdx-001,
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Problem scenario
You want to pass variables from user input and have them carry across multiple pages. You may or may not want the immediate subsequent page to use the variables. You want pages (.php files) after several clicks of navigation (two pages or more) to employ the variables that were read in or calculated via PHP pages.
You are using session_set() and/or session_start() but they are not working.
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Problem scenario
How do you install pycrypto, paramiko and the several related packages without copying several individual packages on a RedHat Linux server?
Background
It can be tedious getting the different dependencies of python packages installed. By downloading various .tar.gz files, you have to unpack them, then run a series of “python setup.py …” commands. While it is not advisable to install more packages than are strictly necessary,
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Problem scenario
You are using RedHat Enterprise Linux 7.x in AWS. How do you install Java?
Possible Solution #1
Use this posting as it is preferred. Below is an alternative.
Possible Solution #2
This will install Java 1.8.x.
1. Create a file named java.sh with this as the content:
yum -y install java-1.8.0-openjdk*
JAVA_HOME=/usr/lib/jvm/jre-1.8.0-openjdk
echo ‘export JAVA_HOME=/usr/lib/jvm/jre-1.8.0-openjdk’ ~/.bashrc
source ~/.bashrc
sudo -s
sudo -s source /etc/environment
2.
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Continue reading “How Do You Install Java on an AWS Instance of RHEL?”
Enterprise Integration Patterns: Designing, Building, and Deploying Messaging Solutions by Gregor Hohpe and Bobby Woolf
Instant RabbitMQ Messaging Application Development How-to by Andrew Keig
Learning RabbitMQ by Martin Toshev
Mastering RabbitMQ by Emrah Ayanoglu, Yusuf Aytas and Dotan Nahum
Production-Ready Microservices: Building Standardized Systems Across an Engineering Organization by Susan J. Fowler
RabbitMQ Cookbook by Sigismondo Boschi and Gabriele Santomaggio
RabbitMQ Essentials by David Dossot
RabbitMQ in Action: Distributed Messaging for Everyone by Alvaro Videla
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Problem scenario
You try to run a compiled Java program. You see the .class file as a result of your compilation. But when you run java ContInt.class, you get this error:
“Error: Could not find or load main class ContInt.class”
How do you run the bytecode (to have your Java program execute after compilation)?
Solution
Omit the “.class” when you run the “java” command.
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Continue reading “How Do You Run (Execute) a Java Program That Compiled Successfully?”
Problem scenario
One of the following applies:
1. You want to install Ansible on an AWS instance of RHEL.
2. You want to install Ansible on a GCP server running RHEL.
How do you do either of these things?
Solution
These directions should work for other RedHat distributions of Linux (e.g., Fedora or CentOS) that are not AWS servers as long as the server has 2 GB of RAM.
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Continue reading “How Do You Install Ansible on an AWS Instance of RedHat Enterprise Linux?”
Problem scenario
You want to install Apache web server on a CentOS, Red Hat Enterprise Linux or Fedora server. What do you do to install it and have the service start running?
Solution
Run these commands:
sudo yum -y update
sudo yum -y install httpd
sudo service httpd start
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Continue reading “How Do You Install Apache Web Server with CentOS/RHEL/Fedora?”
Problem scenario
You have Apache web server installed on Ubuntu. You cannot find httpd.conf. What do you do?
Solution
With Apache2 there is no httpd.conf file. This directory /etc/apache2/ has files like apache2.conf which is related.
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