A Technical I.T./DevOps Blog
Problem scenario
You are using AKS (Azure Kubernetes Service). You have a cluster that you want to have more nodes. (Please do not confuse nodes with pods; see this posting if you are not sure about the difference.) What should you do?
Solution
You need to know the name of the cluster and the resource group it is in.
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Continue reading “How Do You Scale Out the Nodes of an AKS Cluster?”
Question
You have noticed that Docker and Jenkins are regularly used together. Why is this?
Answer
1. The docker build command produces one artifact. Jenkins lends itself to well-defined tasks.
2. The logic and dependencies of the build can usually be completely contained in the Dockerfile (page 20 of Docker Up and Running). Simple lines of text can standardize many aspects of a given build (e.g.,
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Question
What is cargo cult systems engineering?
Answer
Cargo cult systems engineering: vestige stanzas are included in a given configuration file for no functional benefit. Such irrelevant, or environment-inappropriate, stanzas exist either because the systems engineer was not given sufficient time to analyze every line of configuration or because the systems engineer failed to understand why the lines were included in the template (or working system) he/she copied from.
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Problem scenario
You want to use an Azure pipeline. You want it to perform a build. What should you do?
Solution
Prerequisites
i. You must have a supported code versioning system with certain files. As of 10/7/19 the options are Azure Repos Git, Bitbucket Cloud, GitHub, GitHub Enterprise Server, other Git repositories or Subversion. If you follow steps 1 through 4 of How Do You Build a Java Program with Maven?
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Continue reading “How Do You Create a Build Pipeline in Azure?”
Problem scenario
You want a program to test if two words are anagramous with each other. You want the test to be case insensitive. How do you write a program that will interactively prompt the user for two different words and test if they are anagrams?
Solution
Use this Python 3 program (and it will interactively prompt you to enter two words):
word1 = input(“Enter one word: “).lower()
word2 = input(“Enter a second word: “).lower()
wL1 = list(word1)
wL2 = list(word2)
wL1.sort()
wL2.sort()
if (wL1 == wL2):
print(“The two programs are anagrams!”)
else:
print(“The two words are NOT anagrams!”)
It will not work with Python 2.
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Continue reading “How Do You Write a Python Program to Test If Two Words Are Anagrams?”
Problem scenario
You want to use Maven to build a Java program from source code. The code is in at least two different .java files. How do you run Maven to compile a .java file?
Solution
Prerequisites
This assumes that you have installed Maven. If you need assistance, see this posting.
Procedures
1.
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Continue reading “How Do You Build a Java Program with Maven?”
Problem scenario
You want to use Git in an Azure Repository. What do you do?
Prerequisites
You have a Linux VM with Git installed.
Procedures
1. Log into Azure.
2. Go to https://dev.azure.com/
3. Click on “New Project”
4. Enter a project name. For your first project, you should probably have “Project visibility” set to “Private.”
5.
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Problem scenario
You want to deploy the Spring framework with Docker. How do you do this?
Solution
Warning: The last step in this is not a security “recommended practice.” Only follow these directions (with sudo docker run…), if the server is not that important or you are in a very secure network. One published book says you can use “sudo docker …” as long as the server is not in production (page 43 of Docker Up and Running).
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Continue reading “How Do You Install Spring Framework with Docker?”
Problem scenario
You have a multi-node Hadoop cluster running Hadoop version 3. You run this command: hdfs dfsadmin -report
You receive an error that includes this message: “failed on connection exception: java.net.ConnectException: Connection refused; “
What should you do?
Potential Solution
Run these three commands:
bash /usr/local/hadoop/sbin/stop-dfs.sh
hdfs namenode -format
bash /usr/local/hadoop/sbin/start-dfs.sh
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Question
What is a Secret in Kubernetes?
Answer
It is a ConfigMap with sensitive data that is encoded in Base64 text. What is a ConfigMap? It is a .yaml with a special format. There is always a “data:” section that is part of the YAML definition of a ConfigMap. The key-value pairs in the “data” section will have keys that appear in regular text;
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