DEV Community: Sandeep Valpasani

Kubernetes for beginners

Sandeep Valpasani — Sun, 14 Aug 2022 22:15:00 +0000

Before Jumping into Kubernetes, you need to have a good understanding in Docker. And you can checkout Here: Link

What is Kubernetes?

Kubernetes or K8S is an Open-Source Container Orchestration Tool which was originally developed by Google. It is useful for managing container applications in different deployment environments.

What are its uses?

It is useful for building microservice applications.
It is useful for managing n number of containers.

What are the benefits of K8S ?

It has high availability
It gives high performance
Flexibility for developing applications and its components with different stacks.
It is helpful for Backup/Restoring the data.

Kubernetes Components

Pod:

Its smallest unit of K8S
Its useful for building one applicaton
Each Pod has its own IP address

Service:

It has Permanent IP Address
Lifecycle of Service and Pod are not connected
It is useful in Load Balancing

Ingress:

Its useful for hiding the IP Adrress and replacing it with Domain

ConfigMap:

It is useful for storing external configuration of the application.
The text is stored in plain text format, so for storing credentials we have Secret, which is a component in K8S.

Secret:

It is used to store secret data.
The text is stored in base64 format.

Storage:

It can be used in pod and can store in local machine.
Also, outside of the K8S cluster.

Deployment:

It is a blueprint for creating pods.

StatefulSet:

It is useful for building stateful applications or databases.
Its difficult to deploy Applications with StatefulSet.

Kubernetes Architecture:

Node Processes:

Each node has multiple pods.
Each node must be installed with 3 processes.
It acts like worker node to the actual network.
3 processes are Kubelet, Kubeproxy, Container Runtime.
Kubelet interacts with both container and node
Kubelet starts the pod with a container inside.
Kubeproxy forwards the requests.

Master Processes:

There will be four processes running on every master node.

Install Fedora 35 Linux with Windows 11/10 (Dual Boot)

Sandeep Valpasani — Sun, 12 Dec 2021 16:14:17 +0000

Are you curious to work with the Linux Operating System inside your PC/Laptop? Then you're at the right place. This guide helps you in the hassle-free installation of Fedora Linux on your System.

Now, we are going to install Fedora Workstation v35 on our system.

What is Fedora?

Fedora Linux is a Linux distribution developed by the community-supported Fedora Project which is sponsored primarily by Red Hat, a subsidiary of IBM, with additional support from other companies.

If you want to know more about Linux and its distributions, check it out here.

Prerequisites

35GB+ free space in HDD/SSD
8/16GB Pen drive
Windows 11/10

Note: This guide is only for the system which has UEFI BIOS and the type of SSD/HDD is GPT and System Type is x64-based.

How to check the BIOS Mode of your system?

Click Start Button
Search msinfo32 (or) System Information in the search bar
Check BIOS Mode Property

If it's UEFI, you're good to go.

How to check the SSD/HDD Mode of your system?

Click Start Button
Search for cmd
Run cmd as administartor
Type diskpart and press enter.
Next, type list disk and press enter.

If you see * under GPT of Disk 0, you're ready for installation of Fedora Linux in your System.

Softwares Required

Fedora Workstation ISO

Rufus for making USB bootable. Click here to know more.

Now, it's time to create a bootable USB. So, format your USB beforehand.

Create a Bootable USB using Rufus

Open Rufus and plug your clean USB stick into your computer.
Rufus will automatically detect your USB. Click on Device and choose the USB you want to use from the drop-down menu.
Make sure the Boot Selection option is set to Disk or ISO image then click Select. Rufus will open a file explorer browser window, locate the ISO image which you downloaded named Fedora-Workstation-Live-x86_64-XX-X.X.iso to burn onto the USB, and select it.

Leave other options as default and click Start.
You’ll get a warning saying that any data on the USB will be destroyed (this is normal). Click OK and Rufus will start creating the ISO image on the USB.
Let it run in the background, jump to the next section.
Once Rufus has finished creating the ISO image on the USB, you can close it and your bootable USB is ready to go!

Make a new Unallocated Partition.

Press the Windows key + R on your keyboard to open the Run utility, or search for it in the Start menu.
Type diskmgmt.msc and press OK.
A menu will appear with a list of all your hard drives. Right-click on the drive you want to partition and select Shrink Volume.
You'll be asked how much you want the drive to shrink. The amount you enter will be the amount of space left for your new partition. The total size after shrink will be the space left in the original partition.
Enter a value and Click Shrink. (Note: If you want 50GB partition, the value is 50 x 1024 = 51200).
Now, you'll find a new Unallocated Partition under Disk 0.

Reboot your system into BIOS Mode.

To boot into BIOS, Press the below keys before OEM Logo (Brand Logo) appears. the key may be ESC, Del, F1, F2, F10, F12. If still, it's not booting into BIOS, Check the below step.
Google your system model with BIOS mode at the end. You'll find the solution.
After booting into BIOS, disable Secure Boot and Change the Boot Drive priority to USB.
Save the Changes and Reboot.

Boot into Fedora

If all steps have been performed correctly, you will see the below image.

Select Test this media & start Fedora Workstation-Live XX
Wait for some time, you'll see a window with two options.
Click Install to Hard Drive. Again, wait for < 1 min.
You will land on the below Window.

Click on the Keyboard option, Select your Keyboard Language and Click Continue.
Similarly, Click on the Date & Time option, Select your Time Zone and Click Done.

Installation

Now, Click Installation Destination.

Select your disk, Choose Custom under Storage Configuration and Click on Done.

Now, you'll be in the below window and also verify that the Available Space is your Unallocated Partition Space.

Click on the + icon, a popup appears, Choose /boot/efi Under Mounting Point which is System's EFI partition. Enter 1024MiB in Desired capacity. Click on Add mount Point.

Similarly, Click on the + icon again, In popup, Choose / Under Mounting Point which is called Root Partition. Subtract 5GiB from Available Space and Enter remaining space in Desired capacity (Ex: 50 GiB). Click on Add mount Point. And Verify it's Device Type which is Btrfs.

Similarly, Click on the + icon again, In Pop up, Choose swap Under Mounting Point, which is swap memory. Enter the remaining space in Desired capacity (Ex: 5 GiB). Click on Add mount Point.

Finally, you'll see all the partitions created.

Now, click on Done. Verify the Summary of Changes. And click on Accept Changes.

You'll see the below window. Now, click on Begin Installation.

Relax for 10-15 mins.

Click on Finish Installation.

The system will restart automatically and you'll see the GRUB Bootloader, Select Fedora, and Press Enter.

Enter your details and you'll be finally booted into Fedora Linux.

Thanks for following the guide. Hope this helps you in some way :)

AutoPort - Low Code Portfolio Generator

Sandeep Valpasani — Wed, 08 Dec 2021 23:58:59 +0000

My Workflow

AutoPort is a Project for making Portfolio using GitHub Actions. It uses Toha Theme provided by Hugo combined with the power of Github Actions. Thus, making the portfolio application without coding and also without setting up the project on the local system.

Submission Category:

Wacky Wildcards

Yaml File or Link to Code

sandeep-v1404 / autoport

AutoPort 🤖

A Project for making Portfolio using GitHub Actions

It uses Toha Theme provided by Hugo combined with the power of Github Actions.

Sections 📸

Home Page
About
Skills
Experiences
Projects
etc.,

How to use?

Click on Use Template Button. It will create a fork.

Add a new name to the repository and choose private/public. Wait for 2/3 mins.

Click on Settings and scroll down to GitHub Pages and choose gh-pages branch.

Click on Save and Wait for 2/3 mins and refresh the page.

Navigate to the link and you can see the portfoliio.

Click on Issues Tab -> New Issue (Located at Right Side) -> You will see the below page.

Click on Get Started Button in About section.

Modify the content according to your profile and click on Submit Issue

Update the config.yaml file located in root of the repository according to your URL in 1st Line…

View on GitHub

Additional Resources / Info

Hugo: It's The world’s fastest framework for building websites.

Toha Theme: A theme works with Hugo Framework.

Checkout the provided themes here.

I'm thankful to GitHub and DEV platform for the 2021 GitHub Actions Hackathon where I got motivation and resources to work with GitHub Actions.

Docker for beginners

Sandeep Valpasani — Fri, 27 Aug 2021 19:46:27 +0000

We will go through the commands after the basic understanding of Docker.

What is Docker ?

Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers.

What is a container ?

It's used to package application with required dependencies and configuration which the app uses.
It can be easily shared between the team.
It increases efficiency in development and deployment.
Technically, Container is made using Layers of Small Sized Linux Alpine Images with Application Image at top.

Where containers are stored ?

Containers are stored in the form of Images. These Images can be uploaded in

1) Container Repository
2) Private Repo
3) Docker Hub (Public)

Why container ?

In Development

Before Containers	After Containers
Different versions or installation of Applications in each Operating System	A Isolated OS layer with Packaged Applications
Mismatched Configuration	Predefined Configuration
Installation after tedious setup	Installation with one command

In Deployment

Before Containers	After Containers
Environmental Configuration on the servers	Predefined Configuration
Dependencies Version Conflicts	All dependencies are predefined

What is Docker Image and Docker Container ?

Docker Image is the Actual Package.
Docker Container is the running environment of Image which is pulled to local system and is used to start the application.

Docker vs Virtual Machine

To understand how docker works on OS level, lets understand how OS is made.

Operating System has 3 layers:


Application Layer
Kernel Layer
Hardware Layer

In operating System, Application runs on Kernel Layer.

Docker	Virtual Machine
It virtualizes the Application Layer	It virtualizes the Kernel Layer
Docker Image contains the Application Layer	It has both Kernel and Application Layer
It uses host machine's Kernel	It uses it's own Kernel
Smaller in Size	Larger in Size
It starts and runs much faster	Its slower.

Docker Installation :

Docker Basic Commands:

docker pull hello-world

It pulls latest Image of hello-world to local system.

docker pull hello-world:<VERSION>

It pulls specific version Image of hello-world to local system.

docker images

It shows all the images in local system.

docker ps

It lists all the running containers in local system.

docker run hello-world

It checks if image is present,if not present it pulls the image and then runs that image.

docker run -d hello-world

It checks if image is present,if not present it pulls the image and then creates a new container and runs in detached mode and returns ID of that container.

docker stop <ID>

It stops the container with given container ID.

docker start <ID>

It starts the container with given container ID.

docker ps -a

It lists the running and stopped containers.

docker rm <ID>/<NAME> -f

It removes the container with given container ID or name.

docker rm <ID>/<NAME> -fv

It removes the container and the volume associated with it.

docker volume ls

It lists all the volumes and the volume associated with it.

docker rmi $(docker images --filter "dangling=true" -q --no-trunc)

It removes all the volumes which are not in use by the containers.

Port Binding while using two version's of Same Application

As we know, Specific application has a default port in Containers. If we want to use two versions of same application and if both versions run on same port then it is not possible to use the specific one. Then we need to bind the port of container in order to use that Application on the port which is not being used on the local system.

docker run -p<PORT>:<C_PORT> <IMAGE_NAME> (or) <CONTAINER_ID>

where

PORT= System's port on which application should run
C_PORT= Default Container's port on which it runs

docker logs <CONTAINER_ID> (or) <CONTAINER_NAME>

It shows the logs of the container.

docker run -d -p <PORT>:<C_PORT> ---name <C_NAME_BY_USER> <IMAGE>

where

C_NAME_BY_USER = container name given by user
This command changes the name of the container.

docker exec -it <CONTAINER_NAME> /bin/bash

It gives access to the terminal in the container.

docker network create <NETWORK_NAME>

This command creates a new network

docker network ls

Lists all the networks

docker network inspect <NETWORK_NAME>

Gives more information about the container.

Dockerfile

This is how a basic docker file looks like

FROM node:16
WORKDIR /app
COPY package.json .
RUN npm install
COPY . ./
ENV PORT 3000
EXPOSE ${PORT}
CMD ["npm","run","dev"]

Environment Variables

They can be specified in both Dockerfile and command too.

docker run -p 3000:3000 -e PORT=3000 -d --name node-app node-app-image

where -e is option for ENV and also --env can be used.

Persistance in Docker

When a file is changed in the local system, by default it is not updated in the container. We need to make it persistant so that whenever a change is done, it should get updated in the container. This can be achieved by volumes in docker.

docker run -v "$(pwd):/app" -p 3000:3000 -d --name node-app node-app-image

where

$(pwd)= present working directory
/app = working directory in container

Check this out to find why we need to specify "$(pwd):/app" in the command.

Security Practices

After making the docker persistance using above instructions, if you try to add any file using terminal of the container, it will create the file in the container as well as in the local system since it has been synced with volumes. This is not a good practice.To prevent this, we can add :ro in the -v option which means read only. So, it makes container read only, and creating files is impossible.

docker run -v "$(pwd):/app:ro" -v /app/node_modules -p 3000:3000 -d --name node-app node-app-image

Docker Compose

This is how a simple docker-compose.yaml looks like

version: "3"
services:
  node-app:
    build: .
    ports:
      - "3000:3000"
    volumes:
      - ./:/app
      - /app/node_modules
    environment:
      - PORT=3000
    # env_file:
    #   - ./.env

This file can be used to spin up an image and for automatically building the container too.

docker-compose up -d

This command is used to build image and container using docker-compose.yaml file and in detached mode.

docker-compose -f docker-compose.yml -f docker-compose.dev.yml up -d --build

This command is used to build image and container using custom docker-compose.yaml files and in detached mode.

Docker Networks

To make containers talk with each other, we need to use docker networks. By default, we can use IMAGE_NAME in place of IP_ADDRESS which acts as a DNS for the container we want to connect with.


mongoose
    .connect("mongodb://<user>:<password>@mongo:27017/?authSource=admin")
    .then(() => console.log("Successfully connected to DB"))
    .catch((e) => console.error(e));