A Technical I.T./DevOps Blog
Problem scenario
You have an existing GitLab set up on a Linux server. You have access to the back-end. You want to find the port number to connect to. How do you do this?
Solution
First find the external IP address (e.g., curl icanhazip)
Second, install nmap (e.g., sudo yum -y install nmap or sudo apt-get -y install nmap).
Three run this command (but replace x.x.x.x with the IP address found in the first step above):
nmap -Pn x.x.x.x | grep open
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This is a quiz about containers, Docker, and Kubernetes — but mostly about Kubernetes. You can test yourself before a job interview. You may also want to see this list of Kubernetes books.
1. cgroups govern which of the following resources (choose all that apply)?
a. CPU
b. Namespaces
c. Memory
d. Disk I/O rates
2. What does the Docker cache do?
a.
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This is a quiz about containers, Docker, and Kubernetes — but mostly about Kubernetes. You can test yourself before a job interview. You may also want to see this list of Kubernetes books.
1. cgroups govern which of the following resources (choose all that apply)?
a. CPU
b. Namespaces
c. Memory
d. Disk I/O rates
Answer: A, C, and D. Source: Page 157 of Docker Up &
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Question
How do you prepare for a job interview as a software engineer?
Answer
You may want to go to these pages:
Buy books on technical aspects of coding or one that is geared toward technical questions that may be asked. Here are some options:
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Continue reading “How Do You Prepare for a Job Interview as a Software Engineer?”
Problem scenario
You want to write a Python program that will accept a list of integers interactively. You want the program to find and print out the largest number and the smallest number of the list entered. You do not want to use the max() or min() functions (which work in Python 3 without importing any library).
What do you do?
Solution
def extremefinder(mainlist):
a = len(mainlist) – 1
b = len(mainlist)
maxnum = 0
minnum = 0
for x in mainlist:
low = 0
high = 0
for y in mainlist:
if (x y):
low = low + 1
if (low == a): # This never evaluates if x == y. …
Continue reading “How Do You Find the Largest and Smallest Numbers in a Python List in O(N^2) Time?”
Updated on 2/1/22
Tuning relational databases and related processes can be somewhat simple or very complex. OLTP databases have many processes governing the usage of resources. Optimizing these and keeping locks granular and efficient in accord with business requirements is key to having high performance and reliability.
Studying the business requirements carefully can allow you to redesign the database and the SQL queries to make things happen more efficiently.
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Continue reading “Many Ways to Optimize an OLTP Database Running PostgreSQL”
Problem scenario
You want to install pip on a RedHat Enterprise Linux server in AWS. What do you do?
Solution
Prerequisites
This assumes that Python has been installed. If it has not, run this command:
sudo yum -y install python3
Procedures
You may want to try these two commands first:
sudo find / -name pip
sudo find / -name pip3
If the above did not help you,
…
Continue reading “How Do You Install pip on a RHEL Server in AWS?”
Question
Pages are sizes of a database table read from disk and placed into memory (either virtual memory or into RAM). Is a page always 8 KB in a SQL database?
Answer
No. But they are often 8 KB in size.
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Question
What is a difference between a readinessprobe and a livenessprobe besides how the corresponding fields are used in defining a Pod using YAML?
Answer
At most a failed liveness probe will result in the restarting of a container. At most a failed readiness probe will result in the removing a pod from the endpoint of a service (page 150 of Kubernetes in Action).
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Problem scenario
You are used to AWS Security Groups. You created a firewall rule in GCP. You cannot seem to reach the GCP server. What is wrong?
Possible Solution
Does the GCP firewall rule use the same shorthand notation like this?
x.x.x.x/32
Inbound rules in AWS Security Groups use the /32 to allow an IP address to connect to an EC-2 instance or service.
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Continue reading “How Do You Open a Port to Connect to a GCP server?”