A Technical I.T./DevOps Blog
Question
You have seen “MSK” in an article on the public cloud. Does the “K” stand for “Key”? What does MSK stand for?
Answer
MSK stands for “Managed Streaming for Kafka”. It is an Amazon product.
“Amazon Managed Streaming for Apache Kafka (Amazon MSK) is a fully managed service that enables you to build and run applications that use Apache Kafka to process streaming data.
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Problem scenario
You are using an Android phone. When you get new voicemails, there is no indication. What should you do?
Possible solution
Go to the settings in your phone (possibly through a sprocket/gear symbol). Go to Apps -Voicemail. Click on “Force stop” in the lower right hand corner. Allow it to stop. Then click “Open.” This may work.
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Continue reading “How Do You Get the Voicemail Indicator Icon to Work on an Android Phone?”
Problem scenario
You support an existing application and its servers. It is experiencing slowness as the users are complaining about its performance. What are some potential root causes of this slowness?
Possible Solutions
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Continue reading “What Can Cause an Application to Run Slowly?”
Question
You have heard about VPCs and subnets. What are the differences between these two?
Answer
A subnet is a subdivision of a network. Internal to an enterprise network, you may divide the network into different addresses with gateways, routers, bridges and subnet masks. The subnet mask (in CIDR (classless inter-domain routing) notation may be /28, /24, /10 etc.
A VPC ordinarily has its own NACLs and firewalls associated with it;
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Continue reading “What Is The Difference between a VPC and a Subnet?”
Problem scenario
You want to avoid importing any modules in Python. You want to have a way to test if a string is a palindrome is four lines of code. What do you do?
Solution
def is_palindrome_pythonic(s):
return all(a == b for a, b, in zip(
map(str.lower, filter(str.isalnum, s)),
map(str.lower, filter(str.isalnum, reversed(s)))))
# The above four lines of code were taken from page 78 of Elements of Programming Interviews in Python. …
Question
What are guardrails in the I.T. industry?
Answer
A measure, technology or authentication policy in place to prevent problems in an enterprise network or with a application. With guardrails, a server or web application is protected from hackers or accidental misuse. It is a common metaphor based on highway guardrails. To learn more, see this posting:
https://devops.com/building-great-cloud-security-guardrails/
There is a specific product called GUARDRAILS that detects,
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Problem scenario
You want to use Python to get data from BTC transactions. You do not want to use “import requests”. What do you do?
Solution
Prerequisite
This assumes you have installed the Bitcoin pypi package: pip install bitcoin
If you need assistance installing pip, see this posting for Ubuntu or this posting for a Red Hat derivative.
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Continue reading “How Do You Use Python to Retrieve Information about Bitcoin Transactions?”
Problem scenario
You want to use the AWS PaaS offering for exposing an API and having it be able to scale and handle lots of users easily. How do you use Amazon API Gateway?
Solution
Overview: This is a proof-of-concept. You could use different API types (e.g., web socket APIs for persistent applications like a chat window).
Prerequisite
This assumes you have a working Lambda function configured and you know its name.
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Problem scenario
You are using nmap. You try the exact same command with sudo and without sudo. Why are these commands providing different results?
Here are examples of running the exact same command, once with “sudo” and once without:
jdoe@ciserver:~$ sudo nmap -p 9090 192.168.2.25
Starting Nmap 7.80 ( https://nmap.org ) at 2022-01-05 09:56 EST
Nmap scan report for 192.168.2.25
Host is up (0.00056s latency).
PORT STATE SERVICE
9090/tcp closed zeus-admin
MAC Address: 08:00:27:32:27:2C (Oracle VirtualBox virtual NIC)
Nmap done: 1 IP address (1 host up) scanned in 0.25 seconds
jdoe@ciserver:~$ nmap -p 9090 192.168.2.25
Starting Nmap 7.80 ( https://nmap.org ) at 2022-01-05 09:56 EST
Note: Host seems down. …
Continue reading “How Do You Troubleshoot Discrepant nmap Results Based on The sudo Command?”