Describing Containers

• The Basics
• Services and container communication
• Exposing containers externally
• Volumes and Configs
• Multi-Container Pods (Sidecars)
• Special MiCADO/Kubernetes Types (this page)

Stripping away some complexity

You should now have a stronger understanding of TOSCA and our ADTs. To save you some typing when you're preparing your next ADT, we have pre-prepared a number of TOSCA types for Kubernetes in MiCADO that we hope you find convenient.

These TOSCA types either have default interfaces, default properties, or both - meaning that you won't have to write them out again unless you need to overwrite them.

You can always find the current custom TOSCA types for Kubernetes in the main TOSCA repository. Here are four of our favourites:

The Deployment type

tosca.nodes.MiCADO.Container.Application.Docker.Deployment

We use plain Kubernetes Deployments all the time, so we made a type that includes a Kubernetes interface by default.

Use it like this:

my-easy-deployment:
  type: tosca.nodes.MiCADO.Container.Application.Docker.Deployment
  properties:
    image: uowcpc/nginx:v1.2
  requirements:
  - host: my-host

No need to define any interfaces here, that's taken care of by the type!

There are also similar types for DaemonSet and StatefulSet

The EmptyDir Volume type

tosca.nodes.MiCADO.Container.Volume.EmptyDir

Again, we use these alot, so we created a type for them.

Use it like this:

my-easy-deployment:
  type: tosca.nodes.MiCADO.Container.Application.Docker.Deployment
  properties:
    image: uowcpc/nginx:v1.2
  requirements:
  - volume: my-empty

my-empty:
  type: tosca.nodes.MiCADO.Container.Volume.EmptyDir

No properties, no interfaces, just two lines!

The NFS Volume type

tosca.nodes.MiCADO.Container.Volume.NFS

With this type we worked a bit of magic, and moved the NFS server and path options up out of inputs and into properties.

Use it like this:

my-easy-deployment:
  type: tosca.nodes.MiCADO.Container.Application.Docker.Deployment
  properties:
    image: uowcpc/nginx:v1.2
  requirements:
  - volume: my-nfs

my-nfs:
  type: tosca.nodes.MiCADO.Container.Volume.NFS
  properties:
    path: /nfs/share
    server: 10.0.0.2

The path property here still serves as the default mount point in the container, if you don't specify one otherwise.

There is a similar type for HostPath!

The ConfigMap type

tosca.nodes.MiCADO.Container.Config.ConfigMap

We did a similar thing to above, and moved the data and binaryData options up out of inputs and into properties.

Use it like this:

my-easy-deployment:
  type: tosca.nodes.MiCADO.Container.Application.Docker.Deployment
  properties:
    image: uowcpc/nginx:v1.2
    envFrom:
    - configMapRef:
        name: my-config

my-config:
  type: tosca.nodes.MiCADO.Container.Config.ConfigMap
  properties:
    data:
      some: interesting_data

Enjoy!

That's all! See the API Reference for full details