A Technical I.T./DevOps Blog
Problem scenario
You have a Windows laptop with a DVD player. You want to boot to a Linux hard drive from time-to-time. But you do not want to dual boot the same hard drive (where one hard drive supports two different bootable OSes). What should you do?
Solution
You should purchase a hard drive adapter (aka a caddy) made to interface with the internal DVD player connection.
…
Continue reading “How Do You Make Your Laptop Have Two Different OSes?”
Problem scenario
In logs in Azure DevOps or in Linux, you see “ENOENT” frequently. What does ENOENT mean?
Answer
It is a portmanteau of “Error No Entry”. Some directories are not accessible because of permissions issues or because they do not exist. Taken from https://newbedev.com/why-does-enoent-mean-no-such-file-or-directory.
…
Problem scenario
You want Google maps to rotate rectangularly when you use your Android device as a GPS in your car. You want to view the map so the width of the screen and height change 90 degrees based on the way you hold the phone (so it responds to gravity). How do you get the screen to adjust to have a layout that is appropriate for holding the smart phone sideways?
…
Continue reading “How Do You Change the Orientation of Google Maps?”
FDR proclaimed that December 7th would be a day that would live in infamy. Pearl Harbor was attacked in 1941. 80 years later to the day AWS had a major outage (for the us-east-1 region): https://www.theverge.com/2021/12/7/22822332/amazon-server-aws-down-disney-plus-ring-outage
It is an interesting coincidence.
Many people think that the us-east-1 region is the least reliable of Amazon’s regional offerings. Amazon said their “Support Contact Center also relies on the internal AWS network,
…
Question
You want definitions of some I.T. terms. In the context of application/system design, what are reliability, scalability and maintainability?
Answer
Reliability: Dependability or suitable for production; the property of performing consistently over time; worthy of being trusted at all times due to fault tolerance. A system that can perform despite hardware failures or regional data center failures is said to have reliability.
…
Continue reading “What Are Reliability, Scalability and Maintainability?”
Question
What is cyclomatic complexity or McCabe’s complexity?
Answer
It refers to the number of times a line of source code is entered in its execution.
Number of executionsLevel of complexity1 to 10 Not complex11 to 20Moderately complex21 to 50Really complexMore than 50Too complex
It is advisable to endeavor to keep the cyclomatic complexity as low as possible (according to this external site);
…
Question
How do you do a code review?
Answer
Look for consistency in style (adherence to a style guide), functionality, and ensure unit tests and end-to-end tests were performed. Keep an eye out for security issues or maintainability issues. Deploying the code should be straightforward or well documented.
Page 307 of Terraform: Up & Running, 2nd Edition by Yevgeniy Brikman (O’Reilly),
…
Problem scenario
You do not think that Apache web server does virtualization (like a hypervisor). But you see the term Virtual Host when you read about Apache web server configurations. What is a VirtualHost in the context of Apache web server?
Solution
“Apache Virtual Hosts A.K.A Virtual Host(Vhost) are used to run more than one web site(domain) using a single IP address.
…
Continue reading “What is a VirtualHost in Apache Web Server?”
Problem scenario
You want to list the elastic load balancers in your AWS account. How do you view the ELBs?
Solution
Run this command:
aws elbv2 describe-load-balancers …
Continue reading “What is the AWS CLI Command to List Load Balancers?”
Problem scenario
A Linux user creates a file in a directory and no other manual commands are run. The file is associated with a group that is not the group of the user. What could be the reason?
Answer
The directory had a command like this run:
sudo chgrp group2 /path/to/directory
Then the set GID bit was configured. The chmod 2755 /path/to/directory command would set the GID bit because of the “2” in the numeric notation.
…