Deployment and orchestration

Table of contents

Containerization provides an opportunity to move and scale applications to clouds and data centers. Containers effectively guarantee that those applications run the same way anywhere, allowing you to quickly and easily take advantage of all these environments. Additionally, as you scale your applications up, you need some tooling to help automate the maintenance of those applications, enable the replacement of failed containers automatically, and manage the roll-out of updates and reconfigurations of those containers during their lifecycle.

Tools to manage, scale, and maintain containerized applications are called orchestrators. Two of the most popular orchestration tools are Kubernetes and Docker Swarm. Docker Desktop provides development environments for both of these orchestrators.

The advanced modules teach you how to:

  1. Set up and use a Kubernetes environment on your development machine
  2. Set up and use a Swarm environment on your development machine

Turn on Kubernetes

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

Mac

  1. From the Docker Dashboard, navigate to Settings, and select the Kubernetes tab.

  2. Select the checkbox labeled Enable Kubernetes, and select Apply & Restart. Docker Desktop automatically sets up Kubernetes for you. You'll know that Kubernetes has been successfully enabled when you see a green light beside 'Kubernetes running' in Settings.

  3. 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:latest
      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. From the Docker Dashboard, navigate to Settings, and select the Kubernetes tab.

  2. Select the checkbox labeled Enable Kubernetes, and select Apply & Restart. Docker Desktop automatically sets up Kubernetes for you. You'll know that Kubernetes has been successfully enabled when you see a green light beside 'Kubernetes running' in the Settings menu.

  3. 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:latest
      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:

Mac

  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:latest 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:latest       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:latest 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:latest       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 confirmed that you can run simple containerized workloads in Kubernetes and Swarm. The next step is to write a YAML file that describes how to run and manage these containers.

CLI references

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