Kubernetes - Section 0: Resources 🗃️

Description 👀

Resources for the Kubernetes Zero to Pro Guide. Has images, pdfs, and links to other resources.

📁 pdfs

• 📖 kubernetes up and running

  🔗 links

• minikube install
• 🎓 certified kubernetes application developer test
• 💪 exercises for CKAD
• 🙇🏻‍♀️ study materials for CKAD
• 🤔 kubernetes concepts
• 📓 candidate handbook
• 💡 exam tips

Helpful Content 📌

This is a collection of helpful content for the Kubernetes Zero to Pro Guide. It is not a part of Kubernetes, but it is helpful for learning Kubernetes.

YAML

YAML is a human-readable data serialization language. It is commonly used for configuration files and in applications where data is being stored or transmitted. YAML is stored in key value pairs and can be used to serialize data structures such as maps, sequences, and scalars.

YAML Syntax

• YAML is case sensitive
• Comments are created using the # symbol

Examples 🧩

• key value pairs

  Fruit: Apple
  Vegetable: Carrot
  Liquid: Water
  Meat: Chicken
  

• arrays / lists

  Fruits:
    - Orange
    - Apple
    - Banana
  
  Vegetables:
    - Carrot 
    - Cauliflower
    - Tomato
  

• dictionary / map

  Banana:
      Calories: 105
      Fat: 0.4g
      Carbs: 27g
  
  Grapes:
      Calories: 62
      Fat: 0.3g
      Carbs: 16g
  

• key value / dictionary / lists

  Fruits:
    - Banana:
        Calories: 105
        Fat: 0.4g
        Carbs: 27g
  
    - Grapes:
        Calories: 62
        Fat: 0.3g
        Carbs: 16g
  

Notice the alignment, this is important in yaml.

• You can either set a value or a list/dictionary/map but not both

• Dictionaries are an unordered collection while lists are ordered

Docker 🐳

Docker is a containerization platform that allows you to package and run an application in a loosely isolated environment called a container. Docker is a client-server application with the Docker daemon running on the host and the Docker client from the command line or from a program.

How To Create Your Own Image?

• Dockerfile - a text document that contains all the commands a user could call on the command line to assemble an image

  Very Basic Outline:

  1. pick an os. i.e. ubuntu
  2. update apt repo
  3. install dependencies using apt
  4. install dependencies using pip
  5. copy source code into container directory /app, /src, /opt etc.
  6. run the web server, or application

  
  

    # sample Dockerfile for steps outlined above
    FROM Ubuntu
    RUN apt-get update
    RUN apt-get install python
    RUN pip install flask
    RUN pip install flask-mysql
    COPY . /opt/source-code
    ENTRYPOINT FLASK_APP=/opt/source-code/app.py flask run
  

  • all Dockerfiles must start with FROM

• build the image using the docker build command.

  docker build Dockerfile -t <image-name> 
  

  • -t - tag the image

• view image operating system

  docker image inspect <image-name>
  

  or

  docker run <image-name>  cat /etc/os-release
  

Helm

Kubernetes does not care about you application as a whole, it cares about the individual components. Helm is a package manager for Kubernetes that allows you to package up your application as a whole and deploy it to Kubernetes.

Basic Commands 📝

• install application using helm install

  helm install <application-name> <chart-name>
  

• uninstall application using helm uninstall

  helm uninstall <application-name>
  

• view application using helm list

  helm list
  

• view application details using helm status

  helm status <application-name>
  

• upgrade application using helm upgrade

  helm upgrade <application-name> <chart-name>
  

• rollback application using helm rollback

  helm rollback <application-name> <revision-number>
  

Nano 📝

Nano is a text editor that is installed by default on most Linux distributions. It is a simple text editor that is easy to use and has a lot of features. During the CKAD exam, you will be asked to edit a file using Nano or Vim.

• 🗎 nano documentation

Initial Setup 🛠️

• nano config file, ~/.nanorc

    set tabsize 2
    set tabstospaces
  

  • tabsize - sets the number of spaces that a tab will be replaced with

  • tabstospaces - replaces tabs with spaces

  • if ~/.nanorc does not exist, create it

      touch ~/.nanorc
    

Keyboard Shortcuts ⌨️

• editing
  • Ctrl+K Cut current line into cutbuffer
  • Alt+6 Copy current line into cutbuffer
  • Ctrl+U Paste contents of cutbuffer
  • Alt+T Cut until end of buffer
  • Ctrl+] Complete current word
  • Alt+3 Comment/uncomment line/region
  • Alt+U Undo last action
  • Alt+E Redo last undone action
• search and replace
  • Ctrl+Q Start backward search
  • Ctrl+W Start forward search
  • Alt+Q Find next occurrence backward
  • Alt+W Find next occurrence forward
  • Alt+R Start a replacing session
• deletion
  • Ctrl+H Delete character before cursor
  • Ctrl+D Delete character under cursor
  • Alt+Bsp Delete word to the left
  • Ctrl+Del Delete word to the right
  • Alt+Del Delete current line
• moving around
  • Ctrl+B One character backward
  • Ctrl+F One character forward
  • Ctrl+←One word backward
  • Ctrl+→One word forward
  • Ctrl+A To start of line
  • Ctrl+E To end of line
  • Ctrl+P One line up
  • Ctrl+N One line down
  • Ctrl+↑To previous block
  • Ctrl+↓To next block
  • Ctrl+Y One page up
  • Ctrl+V One page down
  • Alt+\ To top of buffer
  • Alt+/To end of buffer

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