Our app on Swarm

In this part, we will:

  • build images for our app,

  • ship these images with a registry,

  • run services using these images.

Why do we need to ship our images?

  • When we do docker-compose up, images are built for our services

  • These images are present only on the local node

  • We need these images to be distributed on the whole Swarm

  • The easiest way to achieve that is to use a Docker registry

  • Once our images are on a registry, we can reference them when creating our services

Build, ship, and run, for a single service

If we had only one service (built from a Dockerfile in the current directory), our workflow could look like this:

docker build -t jpetazzo/doublerainbow:v0.1 .
docker push jpetazzo/doublerainbow:v0.1
docker service create jpetazzo/doublerainbow:v0.1

We just have to adapt this to our application, which has 4 services!

The plan

  • Build on our local node (node1)

  • Tag images so that they are named localhost:5000/servicename

  • Upload them to a registry

  • Create services using the images

Which registry do we want to use?

  • Docker Hub

    • hosted by Docker Inc.
    • requires an account (free, no credit card needed)
    • images will be public (unless you pay)
    • located in AWS EC2 us-east-1

  • Docker Trusted Registry

    • self-hosted commercial product
    • requires a subscription (free 30-day trial available)
    • images can be public or private
    • located wherever you want

  • Docker open source registry

    • self-hosted barebones repository hosting
    • doesn't require anything
    • doesn't come with anything either
    • located wherever you want

  • Lots of 3rd party cloud or self-hosted options

    • AWS/Azure/Google Container Registry
    • GitLab, Quay, JFrog

Using Docker Hub

If we wanted to use the Docker Hub...

  • We would log into the Docker Hub:

    docker login

  • And in the following slides, we would use our Docker Hub login (e.g. jpetazzo) instead of the registry address (i.e. 127.0.0.1:5000)

Using Docker Trusted Registry

If we wanted to use DTR, we would...

This is out of the scope of this workshop!