Get Started, Part 1: Orientation and setup

Estimated reading time: 11 minutes

Welcome! We are excited that you want to learn Docker. The Docker Get Started Tutorial teaches you how to:

  1. Set up your Docker environment (on this page)
  2. Build an image and run it as one container
  3. Set up and use a Kubernetes environment on your development machine
  4. Set up and use a Swarm environment on your development machine
  5. Share your containerized applications on Docker Hub

Docker concepts

Docker is a platform for developers and sysadmins to build, share, and run applications with containers. The use of containers to deploy applications is called containerization. Containers are not new, but their use for easily deploying applications is.

Containerization is increasingly popular because containers are:

  • Flexible: Even the most complex applications can be containerized.
  • Lightweight: Containers leverage and share the host kernel, making them much more efficient in terms of system resources than virtual machines.
  • Portable: You can build locally, deploy to the cloud, and run anywhere.
  • Loosely coupled: Containers are highly self sufficient and encapsulated, allowing you to replace or upgrade one without disrupting others.
  • Scalable: You can increase and automatically distribute container replicas across a datacenter.
  • Secure: Containers apply aggressive constraints and isolations to processes without any configuration required on the part of the user.

Containers are portable

Images and containers

Fundamentally, a container is nothing but a running process, with some added encapsulation features applied to it in order to keep it isolated from the host and from other containers. One of the most important aspects of container isolation is that each container interacts with its own, private filesystem; this filesystem is provided by a Docker image. An image includes everything needed to run an application -- the code or binary, runtimes, dependencies, and any other filesystem objects required.

Containers and virtual machines

A container runs natively on Linux and shares the kernel of the host machine with other containers. It runs a discrete process, taking no more memory than any other executable, making it lightweight.

By contrast, a virtual machine (VM) runs a full-blown “guest” operating system with virtual access to host resources through a hypervisor. In general, VMs incur a lot of overhead beyond what is being consumed by your application logic.

Container stack example Virtual machine stack example

Install Docker Desktop

The best way to get started developing containerized applications is with Docker Desktop, for OSX or Windows. Docker Desktop will allow you to easily set up Kubernetes or Swarm on your local development machine, so you can use all the features of the orchestrator you’re developing applications for right away, no cluster required. Follow the installation instructions appropriate for your operating system:

Enable Kubernetes

Docker Desktop will set up Kubernetes for you quickly and easily. Follow the setup and validation instructions appropriate for your operating system:

OSX

  1. After installing Docker Desktop, you should see a Docker icon in your menu bar. Click on it, and navigate Preferences... -> Kubernetes.

  2. Check the checkbox labeled Enable Kubernetes, and click Apply. Docker Desktop will automatically set up Kubernetes for you. You’ll know everything has completed successfully once you can click on the Docker icon in the menu bar, and see a green light beside ‘Kubernetes is Running’.

  3. In order to confirm that Kubernetes is up and running, create a text file called pod.yaml with the following content:

     apiVersion: v1
     kind: Pod
     metadata:
       name: demo
     spec:
       containers:
       - name: testpod
         image: alpine:3.5
         command: ["ping", "8.8.8.8"]
    

    This describes a pod with a single container, isolating a simple ping to 8.8.8.8.

  4. In a terminal, navigate to where you created pod.yaml and create your pod:

     kubectl apply -f pod.yaml
    
  5. Check that your pod is up and running:

     kubectl get pods
    

    You should see something like:

     NAME      READY     STATUS    RESTARTS   AGE
     demo      1/1       Running   0          4s
    
  6. Check that you get the logs you’d expect for a ping process:

     kubectl logs demo
    

    You should see the output of a healthy ping process:

     PING 8.8.8.8 (8.8.8.8): 56 data bytes
     64 bytes from 8.8.8.8: seq=0 ttl=37 time=21.393 ms
     64 bytes from 8.8.8.8: seq=1 ttl=37 time=15.320 ms
     64 bytes from 8.8.8.8: seq=2 ttl=37 time=11.111 ms
     ...
    
  7. Finally, tear down your test pod:

     kubectl delete -f pod.yaml
    

Windows

  1. After installing Docker Desktop, you should see a Docker icon in your system tray. Right-click on it, and navigate Settings -> Kubernetes.

  2. Check the checkbox labeled Enable Kubernetes, and click Apply. Docker Desktop will automatically set up Kubernetes for you. Note this can take a significant amount of time (20 minutes). You’ll know everything has completed successfully once you can right-click on the Docker icon in the menu bar, click Settings, and see a green light beside ‘Kubernetes is running’.

  3. In order to confirm that Kubernetes is up and running, create a text file called pod.yaml with the following content:

     apiVersion: v1
     kind: Pod
     metadata:
       name: demo
     spec:
       containers:
       - name: testpod
         image: alpine:3.5
         command: ["ping", "8.8.8.8"]
    

    This describes a pod with a single container, isolating a simple ping to 8.8.8.8.

  4. In powershell, navigate to where you created pod.yaml and create your pod:

     kubectl apply -f pod.yaml
    
  5. Check that your pod is up and running:

     kubectl get pods
    

    You should see something like:

     NAME      READY     STATUS    RESTARTS   AGE
     demo      1/1       Running   0          4s
    
  6. Check that you get the logs you’d expect for a ping process:

     kubectl logs demo
    

    You should see the output of a healthy ping process:

     PING 8.8.8.8 (8.8.8.8): 56 data bytes
     64 bytes from 8.8.8.8: seq=0 ttl=37 time=21.393 ms
     64 bytes from 8.8.8.8: seq=1 ttl=37 time=15.320 ms
     64 bytes from 8.8.8.8: seq=2 ttl=37 time=11.111 ms
     ...
    
  7. Finally, tear down your test pod:

     kubectl delete -f pod.yaml
    

Enable Docker Swarm

Docker Desktop runs primarily on Docker Engine, which has everything you need to run a Swarm built in. Follow the setup and validation instructions appropriate for your operating system:

OSX

  1. Open a terminal, and initialize Docker Swarm mode:

     docker swarm init
    

    If all goes well, you should see a message similar to the following:

     Swarm initialized: current node (tjjggogqpnpj2phbfbz8jd5oq) is now a manager.    
    
     To add a worker to this swarm, run the following command:    
    
         docker swarm join --token SWMTKN-1-3e0hh0jd5t4yjg209f4g5qpowbsczfahv2dea9a1ay2l8787cf-2h4ly330d0j917ocvzw30j5x9 192.168.65.3:2377    
    
     To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
    
  2. Run a simple Docker service that uses an alpine-based filesystem, and isolates a ping to 8.8.8.8:

     docker service create --name demo alpine:3.5 ping 8.8.8.8
    
  3. Check that your service created one running container:

     docker service ps demo
    

    You should see something like:

     ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
     463j2s3y4b5o        demo.1              alpine:3.5          docker-desktop      Running             Running 8 seconds ago 
    
  4. Check that you get the logs you’d expect for a ping process:

     docker service logs demo
    

    You should see the output of a healthy ping process:

     demo.1.463j2s3y4b5o@docker-desktop    | PING 8.8.8.8 (8.8.8.8): 56 data bytes
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=0 ttl=37 time=13.005 ms
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=1 ttl=37 time=13.847 ms
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=2 ttl=37 time=41.296 ms
     ...
    
  5. Finally, tear down your test service:

     docker service rm demo
    

Windows

  1. Open a powershell, and initialize Docker Swarm mode:

     docker swarm init
    

    If all goes well, you should see a message similar to the following:

     Swarm initialized: current node (tjjggogqpnpj2phbfbz8jd5oq) is now a manager.    
    
     To add a worker to this swarm, run the following command:    
    
         docker swarm join --token SWMTKN-1-3e0hh0jd5t4yjg209f4g5qpowbsczfahv2dea9a1ay2l8787cf-2h4ly330d0j917ocvzw30j5x9 192.168.65.3:2377    
    
     To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.
    
  2. Run a simple Docker service that uses an alpine-based filesystem, and isolates a ping to 8.8.8.8:

     docker service create --name demo alpine:3.5 ping 8.8.8.8
    
  3. Check that your service created one running container:

     docker service ps demo
    

    You should see something like:

     ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
     463j2s3y4b5o        demo.1              alpine:3.5          docker-desktop      Running             Running 8 seconds ago 
    
  4. Check that you get the logs you’d expect for a ping process:

     docker service logs demo
    

    You should see the output of a healthy ping process:

     demo.1.463j2s3y4b5o@docker-desktop    | PING 8.8.8.8 (8.8.8.8): 56 data bytes
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=0 ttl=37 time=13.005 ms
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=1 ttl=37 time=13.847 ms
     demo.1.463j2s3y4b5o@docker-desktop    | 64 bytes from 8.8.8.8: seq=2 ttl=37 time=41.296 ms
     ...
    
  5. Finally, tear down your test service:

     docker service rm demo
    

Conclusion

At this point, you’ve installed Docker Desktop on your development machine, and confirmed that you can run simple containerized workloads in Kuberentes and Swarm. In the next section, we’ll start developing our first containerized application.

On to Part 2 >>

CLI References

Further documentation for all CLI commands used in this article are available here:

get started, setup, orientation, quickstart, intro, concepts, containers, docker desktop