If you want a great Kubernetes quiz, see this link.
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Problem scenario
You installed Nginx in a Docker container on a RedHat Linux server. You go to this container with a web browser and see the default screen. Where is the default file (on the back-end) that users see from the front-end by default that says “Welcome to nginx!”?
Solution
This is the name and location of the file (assuming the Docker container was created via the public repository):
/usr/share/nginx/html/index.html
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Continue reading “Where Is The “Welcome to Nginx!” Page Stored in a Docker Container?”
Problem scenario
You have a Kubernetes cluster in AWS. You have the AWS CLI installed. How do you find the URL for the Kubernetes cluster?
Solution
1. Run this command: aws eks list-clusters
2. Run this command: aws eks describe-cluster foobar # where “foobar” was name determined in above command
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Problem scenario
You want to manage your Amazon Kubernetes (i.e., EKS) cluster. You have installed the AWS CLI version on a Linux server, and you want to use the update-config or update-kubeconfig command.
But when you try you see messages like “error argument command: Invalid choice…” or “update-config: command not found”. You could not readily find an example. What should you do?
Solution
Background
The command is update-kubeconfig,
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Continue reading “How Do You Use the aws update-kubeconfig Command?”
Problem scenario
You have some Pods in Kubernetes that you want deleted. What should you do?
Solution
1. Find the names. You can run this to find out: kubectl get pods
2. Run this command, but replace “foobar” with the name of the pod you want deleted: kubectl delete pods foobar
3. That should be it. Run kubectl get pods to verify deletion was successful.
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Problem scenario
You run kubectl get pods and you find many or all are not ready. What should you do?
Solution
Run this command: kubectl describe pods
The resulting output should help you.
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Continue reading “How Do You Troubleshoot Kubernetes when Pods Are Not Ready?”
Problem scenario
You have configured a Docker container with a web service (e.g., Apache web server or Nginx). You configured the listening, external port to be 80 or a different port number. You find the web server (either Apache or Nginx) is not working from a web browser. How do you find what is wrong?
Solution
#1 Use nmap to test the port and IP address.
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One or both of the following scenarios applies.
Problem scenario #1
Try to install kubectl, but you get an error message about it being installed.
Problem scenario #2
You run “man kubectl” but you see no man page. You still think kubectl is installed.
What should you do?
Solution
Run this command: kubectl version
The results should give you some clues as to what is wrong.
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Continue reading “How Do You Know if kubectl Is Installed on Your Linux Server?”
Question
What is a container breakout?
Answer
A container breakout is an the act of a user or process in a container gaining access to its underlying host server. Containerization is the isolation of processes and/or disk space on a server. A container is isolated from the host server via cgroups and namespaces. Bypassing the cgroup(s) and namespace(s) through intentional acts can be desirable for legitimate systems engineers.
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Problem scenario
You run this command: sudo kubeadm init
You get this problem: “[ERROR KubeletVersion]: couldn’t get kubelet version: executable file not found in $PATH”
What should you do?
Solution
Install kubelet. See this posting you need assistance. (If it is a Red Hat distribution of Linux, you can try How Do You Install kubectl,
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