Docker in a glimpse

Docker is a great tool for building micro-services, allowing you to create cloud-based applications and systems.
It is a container management service which is based on the concept of Develop, Ship and Run anywhere. To develop apps and ship them into containers which can be deployed on any platform.

With the initial release of Docker technology in March 2013, there was an embarkment of new technical term - Containerization. It has started revolutionizing the old concept of virtualization, where we need to build a complete Guest OS on top of a host OS to run an application.

Virtual machines are resource-intensive as they consumes a lot of resources (compute, memory,etc) in runtime whereas containers are lightweight and boots up in seconds.

Virtualization vs Containerization

Architecture of Docker

The basic architecture of Docker is a Client-Server architecture and consists of 3 major parts:

1. Docker Host - Docker Host runs the Docker Daemon. Docker Daemon listens for Docker requests. Docker requests could be ‘docker run’, ‘docker build’, anything.
It manages docker objects such as images, containers, networks, and volumes.

2. Docker Client - Docker Client is used to trigger Docker commands. It sends the Docker commands through a CLI to the Docker Daemon. It can communicate with more than one daemon.

3. Registry - The Registry is a stateless, highly scalable server-side application that stores and lets you distribute Docker images. You can create your own image and upload it to Docker Hub or any other specified registry.
When we run the command docker pull or docker run, the required images are pulled from your configured registry.

What are containers?

A container is a special type of process that is isolated from other processes. Containers are assigned resources that no other process can access, and they cannot access any resources that are not explicitly assigned to them.

The technology behind the containers!!

Docker containers are evolved from LXC (Linux Containers)
LXC is the well-known and heavily tested low-level Linux container runtime. It is in active development since 2008 and has implemented various well-known containerization features inside the Linux kernel.
The goal of LXC is to create an environment as close as possible to a standard Linux installation but without the need for a separate kernel. To read more about LXC here.

Docker Daemon/Engine is evolved from LXD (LXD daemon)
LXD is a next generation system container manager. It offers a completely fresh and intuitive user experience with a single command line tool to manage your containers. Containers can be managed over the network in a transparent way through a REST API.

Features of Containers:

• Complete isolation - Two containerized processes can run side-by-side on the same computer, but they can’t interfere with each other. They can’t access each other’s data unless explicitly configured to do so.
• Shared physical infrastructure - We don't need separate hardware for running different applications. All can share the same hardware. Shared hardware means lower costs.
• More Secure - Since there is sharing of hardware only but the processes and data being isolated so it becomes very secure.
• Faster scaling of applications - The creation and destroying time for containers is negligible. Even there is no need to purchase the physical infrastructure for scaling up of an application like it used to happen many years ago.

The future of Docker

As the technology shifted from mainframes to PC, Baremetal to Virtualization, Datacenters to Cloud. Now is the time for moving from host to containers (going serverless).

As per the trend analysis, By 2020, more than 50% of the global organizations will be running containers in production.

After going through many articles, I can infer that trend in technology has inclined more towards Kubernetes after DockerCon 2017 as the Swarm (Docker's inhouse container orchestration tool) started seeing a tough competition.

Though the simplicity of the Docker Swarm as the container orchestrator that has taken Docker to this level.

We haven't seen any recent development in Docker Swarm repository from quite a long time. (https://github.com/docker/swarm/wiki)

Even Docker itself has adopted Kubernetes as a container orchestrator.

Is this an indication that the Docker Swarm will be soon out of the picture as more and more industries start adopting Kubernetes in their architecture.

Needless to say that the docker has survived till now and will keep running as an organization, regardless of the speculations that some big organizations will acquire it. There are a lot of new upcoming features and development still going on.

Incorporating cgroups v2 will give Docker better resource isolation and management capabilities.

Adopting P2P model for image delivery and distribute images using something like BitTorrent sync.

Referenced Articles:

https://lwn.net/Articles/788282/

https://www.servethehome.com/kubernetes-wins-docker-acquiesces-adopts-kubernetes/

https://technodrone.blogspot.com/2019/02/goodbye-docker-and-thanks-for-all-fish.html

https://dzone.com/articles/docker-is-dead

https://www.bretfisher.com/the-future-of-docker-swarm/

See you in the upcoming tutorials for taking a deeper dive into Docker.

ESP8266 IOT sensing with Blynk

Basically the internet of things, or IoT, is a system of interrelated computing devices, mechanical and digital machines, objects, animals or people that are provided with unique identifiers (UIDs) and the ability to transfer data over a network without requiring human-to-human or human-to-computer interaction.

Evolution of IOT

The internet of things is also a natural extension of SCADA (supervisory control and data acquisition), a category of software application program for process control, the gathering of data in real time from remote locations to control equipment and conditions.

SCADA systems include hardware and software components. The hardware gathers and feeds data into a computer that has SCADA software installed, where it is then processed and presented it in a timely manner. The evolution of SCADA is such that late-generation SCADA systems developed into first-generation IoT systems.

Designing of our first IOT system

Here we are using ESP8266 Nodemcu module which collects the realtime data from the temperature/humidity sensor (DHT-22) and the soil moisture sensor once every second.

I have created this arduino code where we are collecting this sensor data and sending it over to Blynk hosted API with the help of Blynk libraries.

1. Download the latest library Blynk_Release_vXX.zip file from the GitHub page and extract the zip file to the Library location of Arduino software.
2. Download Blynk App on Android or iOS device and follow these steps for getting started.
3. Download the code from my github repository.

git clone https://github.com/saurabh221089/esp8266_iot_blynk.git

Generate your auth token from app and update it in the code.

char auth[] = "53e4da8793764b6197fc44a673ce4e21";

Change you SSID and Password in the code and flash this code on your ESP module.

char ssid[] = "wifi4u";  //Enter your WIFI Name
char pass[] = "abcd1234";  //Enter your WIFI Password

In the created project on the app, assign the Virtual Pins to the Variables in the program to PULL the data from the API and show it on the app dashboard. 

Blynk.virtualWrite(V5, h);  //V5 is for Humidity
Blynk.virtualWrite(V6, t);  //V6 is for Temperature
Blynk.virtualWrite(V7, m);  //V7 is for Soil Moisture

Flash this code on your NodeMCU module and run the app on the same time to start monitoring.

If you just want to build a static weather monitoring module without any networking involved. You can create a weather monitoring station with ESP8266 and an OLED display.

All the best my friends for your exploration into IOT world. Happy IOTing!!

ESP8266 weather monitor

This tutorial will help you setup your own Weather Monitor with Nodemcu development board on which ESP8266 module is sitting as a microcontroller.

We are going to build a Weather monitor that will show all the vital stats for my home plantation.
Temperature (C), Humidity, Heat Index and Soil moisture percentage. This has helped me to maintain the perfect levels for apt growth of indoor plants.

What is an ESP8266?

The ESP8266 is a System on a Chip (SoC), manufactured by the Chinese company Espressif. It consists of a Tensilica L106 32-bit micro controller unit (MCU) and a Wi-Fi transceiver. It has 11 GPIO pins* (General Purpose Input/Output pins), and an analog input as well. This means that you can program it like any normal Arduino or other microcontroller.

And on top of that, you get Wi-Fi communication, so you can use it to connect to your Wi-Fi network, connect to the Internet, host a web server with real webpages, let your smartphone connect to it, etc. The possibilities are endless! It's no wonder that this chip has become the most popular IOT device available in the market today.

Pre-Requirements

1. Arduino software to upload the .ino sketch on the nodemcu

2. To program the ESP8266, you'll need a plugin for the Arduino IDE, it can be downloaded from GitHub manually, but it is easier to just add the URL in the Arduino IDE:

1. Open the Arduino IDE.
2. Go to File > Preferences.
3. Paste the URL http://arduino.esp8266.com/stable/package_esp8266com_index.json into the Additional Board Manager URLs field.(You can add multiple URLs, separating them with commas.)
4. Go to Tools > Board > Board Manager and search for 'esp8266'. Select the newest version, and click install. (As of Sep 1st 2019, the latest stable version is 2.5.0.)

Components Required

• NodeMCU (ESP8266 development board)
• OLED 128x64 screen
• DHT-22 temperature/humdity sensor
• Capacitive Soil Moisture sensor
• Few jumper cables to connect the components and a breadboard.

Github Repo to clone this project and code

$ git clone https://github.com/saurabh221089/esp8266_weather_monitor.git

Schematic diagram of the complete circuit

If you want to monitor the weather on your Android device when you are outside your home and want to leverage the full potential of ESP8266 module. You can create an IOT enabled weather monitoring station with ESP8266, DHT-22 sensor and Blynk library and monitor the weather from anywhere around the world.