A Technical I.T./DevOps Blog
Problem scenario
You are using Ubuntu with a desktop GUI. You want to create a USB stick with an .iso file to install Linux on some hardware elsewhere. What should you do?
Solution
Remove USB sticks from your computer that will not get the ISO. Why? You may accidentally overwrite one of them.
From the GUI desktop go to the Menu and search for “USB.” You may find “USB Image Writer” or “Startup Disk Creator”.
…
Image via Pexels. Article brought to you by Techdeck.info.
A Budget-Friendly Resource Guide to Tech Investments for Solopreneurs
If you’re a small business owner or solopreneur, keeping overhead costs low is probably a priority. While it’s understandable to save where you can, one area you shouldn’t skimp on is technology. The right tech investments can help streamline your business operations, saving you time,
…
Continue reading “A Budget-Friendly Resource Guide to Tech Investments for Solopreneurs”
Question
In the context of I.T., what does RDM stand for?
Answer (disambiguation)
It can stand for one of the following:
Relational Data Model
Raw Disk Mapping.
(This answer was adapted from page 249 of PowerCLI Cookbook by Sellers.)
…
Problem scenario
You downloaded and installed Hadoop core. But you cannot find the core-site.xml file. What should you do?
Possible Solution #1
Run this: sudo find / -name core-site.xml
Possible Solution #2
Did you download the installation media with a file “-site” in its name?
Try again with a .tar.gz file without “-site” (and without “-src”) in its name:
https://dlcdn.apache.org/hadoop/core/stable/
(This is the for open source version and not a specific vendor’s implementation of Hadoop.)
…
Continue reading “Where Is the core-site.xml File in a Hadoop Installation?”
Problem scenario
You get a “Segmentation fault” or “Segmentation fault (core dumped)” error when you run any “hdfs” command. What should you do?
Solution
Root cause
There is probably an infinite loop/recursion problem. (Segmentation faults involve writing to the stack. Eventually the memory gets filled up.) There is some configuration problem with your Hadoop / hdfs installation.
…
Continue reading “How Do You Troubleshoot “Segmentation fault” Errors in Hadoop/HDFS?”
Question
In the context of databases, Is a B-tree the same as an index?
Answer
For many intents and purposes they are the same.
“B-Tree is a self-balancing search tree.” Taken from
https://www.geeksforgeeks.org/introduction-of-b-tree-2/.
“B-tree is a data structure that store data in its node in sorted order.” Taken from https://dzone.com/articles/database-btree-indexing-in-sqlite.
…
Continue reading “For Databases Is a B-Tree the Same as an Index?”
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.
…
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,
…
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.
…
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?”