A Technical I.T./DevOps Blog
Question
In the context of computers, what is telemetry?
Answer
Telemetry in I.T. is the logged system data transmitted from other servers.
A more detailed definition of telemetry is the utilization of a centralized system to automatically ingest log data from other sources to enable one or more of the following: redundant storage of critical log data, monitoring, data visualization, anomaly detection,
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Question
You have read about high/low level or higher-level (or lower-level) resources and constructs in the context of Kubernetes. What does this designation mean?
Answer
From a high level to a low level we may see a data center, filled with racks, which hold physical servers. Similarly from a high level to a low level we may see Kubernetes nodes supporting pods that have individual Docker containers.
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Problem scenario
You are using Python 2.7.12 on Ubuntu 16. You want to upgrade to Python 3.x You are having problems. You tried several things as follows:
sudo apt-get -y install python 3.7
But you see this:
python is already the newest version (2.7.12-1~16.04).
python set to manually installed.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
…
Continue reading “How Do You Upgrade to Python 3.x on Ubuntu 16?”
Problem scenario
You ran a Hadoop command but you receive this error:
Error: Could not create the Java Virtual Machine.
Error: A fatal exception has occurred. Program will exit.
What do you do?
Solution
Run hadoop help. This error can happen when you have an incorrect flag.
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Continue reading “How Do You Troubleshoot “Error: Could Not Create the Java Virtual Machine”?”
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Problem scenario
You are used to using “input” with Python 3 to prompt the user for a value. How do you pass input when you execute a Python program?
Solution
1. Use import sys
2. Use sys.argv[1] to refer to the first argument passed when you run your program like this:
python3 goodprog.py foo
The program will see “sys.argv[1]” as the string “foo”.
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Problem scenario
You run this command ng –version, but you receive a blank screen at the terminal like this:
—–Mg: scratch (fundamental)—-All——————
What do you do?
Solution
1. Use “ctrl-z” to exit out.
2. Run these commands:
sudo apt remove ng-common
sudo npm uninstall -g @angular/cli
sudo npm install -g @angular/cli
3.
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Continue reading “How Do You Troubleshoot the ng Error “—–Mg: scratch (fundamental)—-All——————“?”
Problem scenario
You have a virtual server running Ubuntu 18.x in Azure. It has Python 2.x. How do you upgrade to Python 3.x?
Solution
1. Run these two commands:
sudo apt -y update
sudo apt -y install python 3.7
2. Find where the binary python3.7 is by running this: sudo find / -name python3.7
Make a mental note of the result.
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Continue reading “How Do You Upgrade Python 2.x to Python 3.7 in Debian or Ubuntu Linux?”
Problem scenario
You want to write a Tic-Tac-Toe program in Ruby. What should you do?
Solution
# Tic-tac-toe game in Ruby. Written by continualintegration.com.
# We know Ruby is object-oriented. Ideally we will re-write this to encapsulate all logic in objects.
puts “This is a two player game of tictactoe. One person can pretend to be the other player.”
puts “Both players should share a keyboard and monitor.”
puts “The legend for squares in the grid is as follows: ”
puts ” ”
puts “***************************************************************”
puts “ltc is left-top-corner, …
Continue reading “How Do You Write a Tic-Tac-Toe Program in Ruby?”
Question
A Kubernetes cluster will have a pod running on a node. The ReplicationController will create a copy (or copies) of a pod to ensure it is available. What is a service in the context of a Kubernetes cluster?
Answer
“A Service in Kubernetes is an abstraction which defines a logical set of Pods and a policy by which to access them.” This quote was taken from https://kubernetes.io/docs/tutorials/kubernetes-basics/expose/expose-intro/
A service is a networking service with a static IP address that connects requests to pods in the Kubernetes cluster (page 48 of Kubernetes in Action by Luksa).
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