Docker Online Training | Kubernetes Online Training

1. What is Docker and When to Use It What is Docker? So what is Docker for? • Docker is great for creating and sharing disc images with others thanks to the Docker index • Docker is an infrastructure manager (the current links concern Linux containers, but future links, in particular KVM, Hyper-V, Xen, etc.) • Docker is an excellent image distribution model for server models built with configuration managers * (like Chef, Puppet, SaltStack, etc.) • Docker uses btrfs (a copy-on-write file system) to keep track of file system differences that can be validated and collaborated with other users (like git) What is not Docker? Before talking about what Docker is, I will talk about what it is not. What is Docker's negation? What are his limits? What can't Docker do? • Docker is NOT Linux container technology (like LXC) • Docker is no longer limited to just LXC (theoretically can manage VMs in the future) • Docker is NOT a replacement for Configuration Manager (like Chef, Puppet, SaltStack, etc.) • Docker is NOT a PaaS • Docker is NOT good for establishing links between separate servers or virtual machines (for now, consult the ambassadors) • Docker is NOT good for isolating Linux containers from each other (shared kernel) When to use Docker? Docker is a basic tool, like git or java, that you should start integrating into your daily development and operations practices. Use Docker as your version control system for your entire operating system

2. Use Docker when you want to distribute / collaborate on the operating system of your application with a team Use Docker to run your code on your laptop in the same environment you have on your server (try the build tool) Use Docker each time your application has to go through several development phases (dev / test / qa / prod, try Drone or Shippable, both make Docker CI / CD) Use Docker with your Chef cookbooks and puppet manifests (remember, Docker doesn't manage setup) What are the alternatives to Docker? The Amazon AMI Marketplace is the closest thing to the Docker index you'll find. With AMIs, you can only run them on Amazon. With Docker, you can run images on any Linux server running Docker. The Warden Project is an LXC manager written for Cloud Foundry without any of Docker's social features like sharing images with others on the Docker Index How Docker is like Java Java's promise: write once. Run anywhere. Docker has the same promise. Except that instead of code, you can configure your servers exactly as you want (choose the operating system, adjust the configuration files, install the binaries, etc.) and you can be sure that your server model will work in exactly the same way on any host running a Docker server. For example, in Java, you write some code: class HelloWorldApp { public static void main(String[] args) { System.out.println("Hello World!"); } }

3. Then run javac HelloWorld.java. The resulting HelloWorld.class can be run on any machine with a JVM. In Docker, you write a Dockerfile: $ FROM ubuntu:13.10 $ ENV DEBIAN_FRONTEND noninteractive $ RUN apt-get update -qq -y && $ apt-get install curl -qq -y && $ apt-get clean $ RUN curl -sSL https://get.rvm.io | bash -s stable –ruby=2.1.1 Then run docker build -t my/ruby . and the resulting container, my/ruby can be run on any machine with a Docker server. The Docker server is like a JVM for systems. It lets you get around the leaky abstraction of Virtual Machines by giving you an abstraction that runs just above virtualization (or even bare metal). Conclusions These collaboration features (Docker Push and Docker Pull) are one of the most disruptive parts of Docker. The fact that any Docker image can run on any machine running Docker is incredible. But The Docker pull / push is the first time that developers and operational operators are able to collaborate easily and quickly to build an infrastructure together. Developers can focus on building great apps and the operational guys can focus on building perfect service containers. The application guys can share application containers with the operations guys and the operations guys can share the MySQL and PosgreSQL and Redis servers with the application guys. For More Information about Docker&Kubernetes ClickHere Ph No: +91-9989971070, E-Mail ID: online@visualpath.in