A Technical I.T./DevOps Blog
Problem scenario
You know how to use Docker containers. You know how to use Docker images if they are already built. Now you want to use a Dockerfile to understand how to build images. How do you use Dockerfile and how do you create your own image?
Solution
Prerequisites
This assumes you have installed Docker on your Linux server. If you have not,
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Continue reading “How Do You Create a Dockerfile and Build a Docker Image?”
Problem scenario
You have two configuration management servers: one is an Ansible control server and another is a Salt Master server. You want Ansible to deploy Salt Minion to the managed nodes. You want the managed nodes of Ansible to receive configurations from the Salt Master server. This way one team can use SaltStack and another team can use Ansible. How do you do this?
Solution
Prerequisites
This assumes you have deployed Salt Master and Ansible.
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Continue reading “How Do You Leverage Ansible to Deploy Salt Minion to an Ansible Managed Node?”
Problem scenario
You want Ansible to create directories on managed nodes. How do you write a playbook to do this?
Solution
Prerequisites
This assumes that you have installed and configured Ansible. If you do not know how to deploy Ansible, see this posting if you are using a Red Hat derivative. If you are using Linux SUSE,
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Continue reading “How Do You Get Ansible Playbooks to Create Directories on Managed Nodes?”
Problem scenario
You want to find out how much disk space you will consume before you install a given yum or RPM package. You want to list available packages and their size based on a near match of a name. What is the Linux (e.g., yum) command to find size of the package before you actually install it?
Solution
Prerequisites
This assumes that you have installed yum-utils.
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Continue reading “How Do You Find the Size of an RPM Package before You Install It?”
Problem scenario
You have Linux servers of different distributions (including Debian/Ubuntu, Red Hat derivatives such as CentOS, RHEL, or Fedora, and Linux SUSE). You want to install npm and Node.js on them. What do you do?
Solution
Prerequisites
i. You need a server with at least 1 GB of RAM. To add virtual memory, see this posting.
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Continue reading “How Do You Install npm and Node.Js on Any Distribution of Linux?”
Problem scenario
You run a PowerShell command with a user who is not a local administrator on the server. You get the error “Cannot connect to CIM server: Access is denied”. How do you circumvent this error?
Possible solution #1
Make the user a local administrator. Then try again.
Possible solution #2
Use JEA to allow the user to run the command.
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Problem scenario
You run a PowerShell command. You get “Cannot find Get-Command” even though the command you entered was not Get-Command. How do you solve this error?
Possible Solution #1
As an Admininstrator of the server, go to Server Manager -Tools -Computer Management. In this Window (or MMC) go to System Tools -Local Users and Groups -Users. Double click on the User that received the error.
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Continue reading “How Do You Troubleshoot the Powershell Error “Cannot find Get-Command”?”
Problem scenario
You are familiar with functions in programming languages (e.g., Python or SQL). You like how you can create a modular program with a function. Functions can allow you to reuse code and do data processing in a way that is readable. Logic can be created rapidly when you know how to use a function. How do you write a function in the C?
Solution
Prerequisites
Install the C compiler.
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Continue reading “How Do You Create a Function in the C Programming Language?”
Problem scenario
You try to compile a program with “gcc nameofprog.cc”. You get this output: “foobar.cc.:55:error: expected ‘;’ before string constant”
What do you do to compile your program?
Solution
Go to line 55 of foobar.cc. If there is a printf command, be sure that the thing to be printed is surrounded by parentheses. Here is an example of a line that will cause the problem:
printf “This is a test”;
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Problem scenario
You try connect via your wireless router to a WiFi network (e.g., at a restaurant, hotel, or public library). You open a web browser because you were told you would be prompted with a splash screen. On this page you would agree to the terms of service and/or enter a password. You are not seeing this web page. You try different URLs (e.g., www.yahoo.com, www.google.com). You are never prompted for a username or password.
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