A Technical I.T./DevOps Blog
Problem scenario
For a boto3 program, you want to find the AWS namespaces. What do you do to list the namespaces that are part of your AWS accounts?
Solution
Prerequisites
You must have the AWS CLI installed. If you need assistance with this, see this posting.
This also assumes that the Linux user has the policy for servicediscovery:ListNamespaces.
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Problem scenario
You have a Red Hat derivative of Linux. You want to install Flask. What should you do?
Solution
Prerequisites
Install pip. If you need assistance, see this posting.
Procedures
Run this command: sudo pip3 install flask
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Continue reading “How Do You Install Flask on a CentOS/RHEL/Fedora Server?”
Problem scenario
The security team for your enterprise will not permit Python 2 to be installed. (You do not want to install a new minimal Python package either.) How do you fix the problem of env: ‘python’: No such file or directory when you run a make command?
Solution
The command “python” (not python3), will work after you run this script. Run this script as sudo (e.g.,
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Problem scenario
You installed CraftCMS. But there is no port activity on port 80. You want to go to the front-end now. You cannot get to it via a web browser. What do you do?
Solution
Is there a firewall or public cloud security group (e.g., an Azure Network Security Group) blocking traffic to the public IP address over port 80? GCP’s firewall could block HTTP traffic such that nmap commands would not show activity over port 80.
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Problem scenario
You want to set up Rundeck to see what it is like. How do you do this on a Debian distribution of Linux (e.g., Ubuntu, Kali Linux, or Linux Mint)?
Solution
Prerequisite
Java must be installed. Use this posting if you need help with that. We recommend a 4 CPU server with at least 8 GB of RAM.
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ABRIDGED VERSION (To see the unabridged version, see this posting.)
Problem scenario
A Puppet manifest is not working, but there are no obvious error messages. When running the puppet agent command, you use the -d flag for debugging. In your manifest, you use logoutput => true stanza. But still, you cannot figure out why your manifest is not working.
You tried this command: puppet parser validate nameOfManifest.pp
The above command had no output.
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Problem scenario
You are not sure if environmental specific values should be placed into version control. What should do you?
Solution
Some people think that everything should go into version control. But others disagree. Here are examples of each philosophy:
“You need to get everything in version control. Everything. Not just the code, but everything required to build the environment.” (This was taken from page 297 of The Phoenix Project.) This is very clear in how it disagrees with the twelve-factor app principles.
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Continue reading “Should Environmental Data Be Placed Into Version Control?”
Question
What is the difference between unit testing and functional testing in the context of professionals using one over the other?
Answer
A user wants to verify that the software behavior is correct from a black-box perspective; this more closely describes functional testing. A programmer is more concerned about the theoretical aspects of the code and its inner workings; this more closely describes unit testing.
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Continue reading “What Is The Difference between Unit Testing and Functional Testing?”
Problem scenario
You want to use the reserved word “next” to parse through an iterable. What do you do?
Solution
Run this six-line program as an illustration:
contint = [ 15, 50, -100, ‘foobar’]
var1=iter(contint)
print(next(var1))
print(next(var1))
print(next(var1))
print(next(var1)) …
Continue reading “How Do You Use the “next” Function to Iterate Through an Iterable in Python?”
Problem scenario
You want to set up Apache Kafka with a single broker just to test out. How do you do this on any distribution of Linux?
Prerequisite
You must install Zookeeper. If you need assistance, see this posting.
You may want to install screen because this solution will rely on it; you could open duplicate terminals instead of using the screen command.
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Continue reading “How Do You Set Up Apache Kafka on Any Distribution of Linux?”