breakfast.md

Demo: configure breakfast

Define a place to work:

DEMO_HOME=$(mktemp -d)

Make a place to put the base breakfast configuration:

mkdir -p $DEMO_HOME/breakfast/base

Make a kustomization to define what goes into breakfast. This breakfast has coffee and pancakes:

cat <<EOF >$DEMO_HOME/breakfast/base/kustomization.yaml
resources:
- coffee.yaml
- pancakes.yaml
EOF

Here's a coffee type. Give it a kind and metdata/name field to conform to kubernetes API object style; no other file or definition is needed:

cat <<EOF >$DEMO_HOME/breakfast/base/coffee.yaml
kind: Coffee
metadata:
  name: morningCup
temperature: lukewarm
data:
  greeting: "Good Morning!"
EOF

The name field merely distinguishes this instance of coffee from others (if there were any).

Likewise, define pancakes:

cat <<EOF >$DEMO_HOME/breakfast/base/pancakes.yaml
kind: Pancakes
metadata:
  name: comfort
stacksize: 3
topping: none
EOF

Make a custom variant of breakfast for Alice, who likes her coffee hot:

mkdir -p $DEMO_HOME/breakfast/overlays/alice

cat <<EOF >$DEMO_HOME/breakfast/overlays/alice/kustomization.yaml
commonLabels:
  who: alice
resources:
- ../../base
patchesStrategicMerge:
- temperature.yaml
EOF

cat <<EOF >$DEMO_HOME/breakfast/overlays/alice/temperature.yaml
kind: Coffee
metadata:
  name: morningCup
temperature: hot!
EOF

And likewise a variant for Bob, who wants five pancakes, with strawberries:

mkdir -p $DEMO_HOME/breakfast/overlays/bob

cat <<EOF >$DEMO_HOME/breakfast/overlays/bob/kustomization.yaml
commonLabels:
  who: bob
resources:
- ../../base
patchesStrategicMerge:
- topping.yaml
EOF

cat <<EOF >$DEMO_HOME/breakfast/overlays/bob/topping.yaml
kind: Pancakes
metadata:
  name: comfort
stacksize: 5
topping: strawberries
EOF

One can now generate the configs for Alice’s breakfast:

kustomize build $DEMO_HOME/breakfast/overlays/alice

Likewise for Bob:

kustomize build $DEMO_HOME/breakfast/overlays/bob