Does Chef Use a DSL?

Question
You are not sure if Chef uses pure Ruby or a DSL based on Ruby or Erlang. Does Chef use a Domain Specific Language?

Answer
It uses a Ruby-based domain specific language. The sources are as follows:

https://docs-archive.chef.io/release/12-0/dsl_recipe.html
https://cloudacademy.com/course/getting-started-chef/the-recipe-dsl/

What States Have Double Taxation on Income for Remote Workers?

Problem scenario
"People who work in a state they do not live in may be subject to income tax withholding for both states." (This quote was taken from https://www.shrm.org/resourcesandtools/legal-and-compliance/employment-law/pages/hybrid-work-legal-challenges.aspx.)

You read that some states make the remote employee pay income tax in addition to other taxes where the employer is located. What states are these?

Answer
Arkansas, Connecticut, Delaware, Massachusetts, Nebraska, New York, and Pennsylvania. Sometimes another state (the state your employer is in) will give you a credit if you live in one of these states.

The source this answer is
https://www.adp.com/spark/articles/2022/11/remote-and-hybrid-workers-state-tax-incentives-and-compliance-challenges.aspx

How Do You Troubleshoot the Error “req: Use -help for summary”?

Problem scenario
You run a command like this:

sudo openssl req -newkey rsa:2048 -nodes -keyout contint.key -x509 -days 9999 contint.crt

You get this as the output: "req: Use -help for summary."

What should you do?

Possible Solution #1
Use the "-out" flag between "9999" and "contint.crt".

Possible Solution #2
Do you have an extra "-new" flag in your command? There may be an extraneous flag that should not be there.

Possible Solution #3
Can you simplify the command? Complex commands with potential escape characters could create confusion. To isolate the problem, start with a simple version of what you are trying to run. Then start using arguments of a greater complexity on that working command.

Possible Solution #4
See this serverfault.com posting.

How Do You Troubleshoot “jdoe is not authorized to run that command as root”?

Problem scenario
You failed to use visudo on a Red Hat or Debian distribution of Linux. You try to elevate your user to sudo and run a command but you get: "jdoe is not authorized to run that command as root."

You forgot the root password. You cannot boot into rescue/recovery mode. How do you correct the /etc/sudoers file?

Solution
Run "pkexec" without quotes. If the user has sudoer privileges, it should work to gain access as root.

What Is The Space Complexity when There Are Two Variables in a Program?

Question
You have a program with two (or three) variables, but no other data structures. What is the space complexity?

Answer
O(1). An algorithm, as long as the number of variables is fixed, can have 1,000 variables and be said to have O(1) space complexity. The source is here:

https://stackoverflow.com/questions/43260889/what-is-o1-space-complexity

How Do You Get a USB-to-Ethernet Cable to Work with Linux?

Problem
You connect a USB convertor (for a wired ethernet cable) to your Linux laptop. It isn't working as a plug-and-play device. What could be wrong?

Solution
1. In the GUI on the Linux desktop, go to "Settings" or "Control Settings". 2. Then go to "Network".
3. Click a plus sign "+" (to add a new profile).
4. On the Identity tab, of the pop-up, there should be one or two MAC addresses in the drop down option.
5. Choose one and click "Add." Give it a few minutes.
6. If step #5 doesn't work, try again, but try a new "MAC Address" in the drop down. Give it a few minutes and see if the network is showing up.

How Do You Troubleshoot “…quota: Cannot open quotafile //aquota.user: Permission denied”?

Problem scenario
You run a quota command. But you get "quota: Cannot open quotafile…" //aquota.group or //aquota.user … "Permission denied."

What should you do?

Possible Solution #1
Maybe you do not have permissions. Can you run it with "sudo "?

If you run it with sudo and just see the quota governing the root user, then try running a command like this:

sudo quota -u jdoe
# Replace "jdoe" with the non-root user

You may want to find the relevant files with commands like this: 

sudo find / -name aquota.group
sudo find / -name aquota.user

Possible Solution #2
This assumes you have the chattr utility installed; if you need assistance, see How Do You Install chattr on Ubuntu?

Change the immutable bit with this:

cd /path/to/aquota.user # change directories to the one with the file
sudo chattr -ia aquota.user

This was adapted from https://www.thecpaneladmin.com/aquota-user-permission-denied/.

Possible solution #3
You could try running a quotacheck command (e.g., sudo quotacheck -vug). This solution was adapted from https://sourceforge.net/p/linuxquota/bugs/94/.
This command can clear the immutable bit. If you want to read about the immutable bit, see What Is the Immutable Bit vs the Sticky Bit?

How Do You Fix Apache Kafka when It Hangs?

Problem scenario
You try to start the Apache Kafka service. You get this:

[2021-07-25 12:15:36,687] INFO [Group Metadata Manager on Broker 1]: Finished loading offsets from [__consumer_offsets,24] in 123456789 milliseconds.

GroupMetadataManager…Finished loading offsets and group metadata from __consumer_offsets…seconds spent in the scheduler. (kafka.coordinator.group.GroupMetadataManager)

It just hangs and will not progress. What do you do?

Solution
Whenever a command hangs that is supposed to start a service, there could be one, ignorable errors. The problem could be obviated by a service that runs the command in the background. How did you start the Kafka service? Did you use the flag "-daemon"?

Try this:

kafka-server-start.sh -daemon /root/kafka/config/server.properties

Taken from http://tecmint.com/install-apache-kafka-in-centos-rhel/

Why Are Ubuntu Versions (the Corresponding Integer Number Values) Usually Even?

Problem scenario
You are curious why the odd versions of Ubuntu get so little attention. Why is this?

Answer
Even versions get long term support. If you are uncertain which version of Ubuntu to install, we recommend the highest even number release. As of February 2022, this is Ubuntu 22.x.

See this for more information: https://ubuntu.com/about/release-cycle

Be advised that odd versions will have an end of life that is sooner than the end of life for the previous even version. If your server will last more than one year it is important to use an even version (in most situations).