A Technical I.T./DevOps Blog
Problem scenario
You wrote a Dockerfile. You are using it to try to create a Docker image. When you run the “docker build” command you get some error messages. The errors include one or more of the following:
1) A MarkupSafe fatal error related to Python.h.
2) A C extension not being compiled.
3) An invalid syntax error related to async (e.g., “Jinja2/jinja2/asyncfilters.py”).
You need to base the image off Ubuntu.
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Problem scenario
You use del and pop to remove items from lists. You noticed that pop is slower than del. Why is this the case?
Solution
There are two reasons. One, pop returns the value that is removed. Two, pop acts as a function call as opposed to a primitive action. Whereas the del invokes a primitive action (a non-recursive function call),
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Continue reading “When Manipulating Lists in Python, Why is pop Slower than del?”
Problem scenario
You want to use the MVC model without Microsoft technologies. You want to try out the Spring framework to leverage its inverse-of-control. How do you quickly deploy the Spring framework?
Solution
Prerequisites
i. This assumes that you have installed Git. If you need to install it, try this command:
sudo yum -y install git
ii.
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Continue reading “How Do You Deploy Spring Framework in RHEL?”
Problem scenario
You recently migrated to WordPress. There are small windows of text on the left or right side of your blog. They are not posts. You do not know how to modify them. What should you do to modify them or add advertisement banners to your website?
Solution
These sidebar text rectangles are called “Footers” in WordPress. To modify them, delete them,
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Continue reading “How Do You Get to the Small Windows (aka Widgets) in WordPress?”
Problem scenario
You have C++ installed. You want to know what version it is. What do you do?
Solution
Possible solution #1
Run this command: /usr/bin/cpp -v
Look for the word “version”. Use CTRL-c to exit out.
Possible solution #2
Run these two commands:
. /opt/intel/bin/iccvars.sh intel64
icc -v
(Taken from https://superuser.com/questions/465949/how-to-know-what-version-of-c-compiler-is-installed-on-linux-server)
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Continue reading “How Do You Find what Version of C++ Is Installed?”
Problem scenario
You want to see if the immutable flag is set on a file. What do you do?
Solution
Run this command: sudo apt -y install e2fsprogs
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Problem scenario
You get “command not found” when you try to run “chattr”. What should you do?
Solution
Run this command: sudo apt -y install e2fsprogs
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Question
Ping is a common diagnostic tool in networking technology. It is essentially an echo request to confirm an IP address is up and accessible. Where does the term ping come from?
Answer
The acronym for “packet inter-network groper” seems like it is a backronym for the trademarked table tennis game which involves a lightweight ball being returned in the opposite direction that it was sent.
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Problem scenario
How do you find files on a Linux server that consume more than one gigabyte of space?
Solution
Run this command: sudo find / -size +1G -type f -print
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Continue reading “How Do You Find Files on a Linux Disk That Are larger than One Gigabyte?”
Problem scenario
Docker Hub is a public registry for containers. Does OpenShift support something like this? You know they have the OpenShift Container Registry — but this is private to a given OpenShift instance. Red Hat owns OpenShift. Is there a public registry supported by Red Hat?
Answer
Yes. It is called Quay.io. If you want a brief overview of it,
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Continue reading “Is there a Docker Hub equivalent for OpenShift?”