A Technical I.T./DevOps Blog
Problem scenario
You want to implement a secure protocol for authentication. You want there to be a password and a second factor of authentication. Can an email (being in possession of an inbox) be a factor in MFA?
Answer
Maybe.
No, according to NIST:
https://pages.nist.gov/800-63-FAQ/
But many companies do use email as a factor in multi-factor authentication.
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Problem scenario
You go to hotels with mini-refrigerators. What appears to be a small fridge is actually a freezer from a pragmatic perspective. Your food (e.g., apples or fruit) get destroyed when they are frozen. You want a fridge, but everything seems to freeze your food. What should you do?
Solution
Turn the temperature down. If you open the fridge and do not see a thermostat,
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Continue reading “How Do You Get Hotel Refrigerators to Not Freeze Your Food?”
Problem scenario
You find out-of-memory (aka OOM) errors in Kubernetes. The node seems healthy. The pods keep restarting. What should you do?
Possible Solution #1
Are you using a burstable quality of service (aka QoS) with the pods? There may be a non-pod-specific reason and the burstable Pods are being starved of resources. The node may be getting requests for other pods with a superior quality of service.
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Continue reading “How Do You Troubleshoot OOM Errors with Restarting Pods in Kubernetes?”
Problem scenario
You want to see what dnf packages are available for installation.
The command “sudo dnf list available packages” does not work. How do you list the dnf packages that are available?
Solution
Run this command:
sudo dnf list …
Continue reading “How Do You List dnf Packages That Are Available?”
Problem Scenario
You run an HDFS command, but you get this message: “ERROR: Hadoop common not found”
What should you do?
Solution
As the hduser or user that runs hdfs, log in. Run “echo $HADOOP_HOME”
That directory should have a libexec directory with a file called hadoop-config.sh.
Run this: ls -lh $HADOOP_HOME/libexec
One way to create it is this: 1) find a hadoop-config.sh file (e.g.,
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Continue reading “How Do You Troubleshoot “ERROR: Hadoop common not found” when Running Hadoop?”
Question
In computing, what is the definition of a schema?
Answer / schema disambiguation
Outside of the I.T. realm, Merriam-Webster’s Dictionary (11th Edition, on page 1110) defines schema as “a diagrammatic presentation; broadly: a structured framework or plan: outline.” This definition must have influenced the appropriation of the word to refer to concepts in I.T..
For Kubernetes
“Schemas are the set of JSON files for various Kubernetes versions,
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Question
Some of the signers of the Declaration of Independence invented new musical instruments. Who were they and what did they invent?
Answer
Francis Hopkinson invented the Bellarmonic that involved steel bells (https://loc.gov/item/ihas.200035713). Ben Franklin invented the armonica (https://pubmed.ncbi.nlm.nih.gov/11855437/). To listen, click on this: https://www.youtube.com/watch?v=eEKlRUvk9zc
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Digital Upgrades to Keep Your Business From Falling Behind
Businesspop.net shares a post today intent on helping small businesses get ahead in the digital age.
As a small business owner, you have a lot on your plate. You have to keep your profits in the black, make sure that your customers are happy, and ensure your employees have the tools they need to be effective.
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Continue reading “Digital Upgrades to Keep Your Business from Falling behind”
Problem scenario
You run “sudo usermod -aG wheel jdoe” but you get “usermod: group ‘wheel’ does not exist.” What should you do?
Possible solution #1
Run this:
sudo usermod -aG admin jdoe
Some Linux distributions such as Ubuntu* use “admin” instead of “wheel”
You may want to read this for further information.
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Continue reading “How Do You Troubleshoot the Error Message “usermod: group ‘wheel’ does not exist””
Problem scenario
You modified the /etc/sudoers file. The changes do not seem to have taken effect. What should you do?
Solution
99% of the time you do not need to log out or log back in. You should not need to open another terminal. For the stanza that you added, did you append it to the bottom? The problem may be that the stanza you added was in the middle of the file.
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Continue reading “How Do You Troubleshoot /etc/sudoers Changes Not Working?”