A Technical I.T./DevOps Blog
Problem scenario
Use PDF Architect or Adobe Acrobat you open a PDF but you see “Please wait… If this message is not eventually replaced by the proper contents of the document, your PDF viewer may not be able to display this type of document.” You know the PDF is good. You may or may not be prompted to enter a password to view the PDF. You don’t think that the PDF viewer should be prompting you for a password.
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Question
With a newer version of Jenkins, you want to know what a multi-branch job is. What is a multi-branch Jenkins job?
Answer
In Jenkins, a project is a job; the term job has been deprecated however (according to the Jenkins’ website). To see the difference between a Jenkins pipeline and a Jenkins project, see this posting: What Is the Difference between a Jenkins Project and a Jenkins Pipeline?
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Problem scenario
You have an Nginx server that you want to be a traffic distributor to Apache web servers. What has to be done to configure Nginx’s HTTP load balancing function to relay inbound connection requests to Apache web servers?
Solution
Nothing special has to be done for the web servers. Nginx can be a reverse proxy to either Nginx web servers or Apache web servers. The “upstream backend {}” block in the file /etc/nginx/conf.d/default.conf in Nginx’s distributor instance merely has to have stanzas like these:
upstream backend {
server apache.web.server.com;
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Continue reading “How Can Nginx Be an HTTP Load Balancer for Apache Web Servers?”
Problem scenario
You run a command like this:
aws s3api create-bucket –bucket coolnameforbucket
But you get this error:
“An error occurred (IllegalLocationConstraintException) when calling the CreateBucket operation: The unspecified location constraint is incompatible for the region specific endpoint this request was sent to.”
How do you create a bucket with the aws s3api command?
Possible Solution #1
Run a command such as this,
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Problem scenario
You want to use a Data Analytics or a Big Data tool that publishes messages and subscribes to listening to messages being published. You know GCP has a Pub/Sub tool. You know it supports synchronous and asynchronous messaging. How do you use it with Python?
Solution
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Continue reading “How Do You Use Google’s Cloud Pub/Sub with Python?”
Problem scenario
You want to install RabbitMQ on any distribution of Linux using the same script. How do you write such a script?
Solution
1.a. If you are using SUSE or a Red Hat deriviative of Linux (e.g., CentOS/RHEL/Fedora), go to step #2.
1.b. If you are using Debian or Ubuntu Linux, read the following. There may be manual steps (often three steps with Ubuntu 18.04 in AWS).
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Continue reading “How Do You Install RabbitMQ Server on Any Distribution of Linux?”
Problem scenario
You wrote a Python program on a Linux machine, and it works by interactively prompting a user for input. You want it to work for HackerRank, but you are not sure how standard input works in their platform. You use this line of code in your program: ‘input(“Enter your input here: “)’ to ask the user for input. This does not work in HackerRank.
You tried rewriting your program to accept parameters when you run it like this:
python foobar.py blue
In foobar.py you have “sys.argv[1]” to accept the “blue” argument.
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Continue reading “How Is Input Passed into the Python Program in HackerRank.com?”
Problem scenario
You have a URL that works with a curl command (with the -X POST option). You need to get wget to do a POST like curl. You are having trouble getting wget to work. wget returns 403 forbidden errors, but the destination address is the same. It seems as though the source server is different and potentially causing the problem (e.g, by virtue of its IP address). You do not think,
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Continue reading “How Do You Get wget to Work when curl Commands Are Successful?”
Problem scenario
You are trying to fix a Kubernetes problem. You read that you need to check the context to solve your problem. How do you determine what context you are using?
Solution
Run this command:
kubectl config current-context
Or try this command:
kubectl config get-contexts
Another command that may be interesting is this one:
kubectl config view | grep -i context
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Continue reading “How Do You Find What Context Your Kubernetes Configuration Is Using?”
Problem scenario
You run this command:
kubectl get cluster-info
You receive this error message:
“Unable to connect to the server: dial tcp: lookup ABCDEFGHIJKLMNOPQRSTUVWXYZ123456789.yl4.FQDN.com on 172.55.44.33: no such host”
Solution
Possible solution #1
Ask yourself these three questions:
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