breakfast

demos/breakfast.md

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+[kubernetes API object style]: https://kubernetes.io/docs/concepts/overview/working-with-objects/kubernetes-objects/#required-fields
+
+# Demo: configure breakfast
+
+
+Define a place to work:
+
+<!-- @makeWorkplace @test -->
+```
+DEMO_HOME=$(mktemp -d)
+```
+
+Make a place to put the base breakfast configuration:
+
+<!-- @baseDir @test -->
+```
+mkdir -p $DEMO_HOME/breakfast/base
+```
+
+Make a `kustomization` to define what goes into
+breakfast.  This breakfast has coffee and pancakes:
+
+<!-- @baseKustomization @test -->
+```
+cat <<EOF >$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:
+
+<!-- @coffee @test -->
+```
+cat <<EOF >$DEMO_HOME/breakfast/base/coffee.yaml
+kind: Coffee
+metadata:
+  name: morningCup
+temperature: lukewarm
+data:
+  greeting: "Good Morning!"
+EOF
+```
+
+The `name` field merely distinguishes this instance of coffee from others (if
+there were any).
+
+Likewise, define _pancakes_:
+<!-- @pancakes @test -->
+```
+cat <<EOF >$DEMO_HOME/breakfast/base/pancakes.yaml
+kind: Pancakes
+metadata:
+  name: comfort
+stacksize: 3
+topping: none
+EOF
+```
+
+Make a custom version of breakfast for Alice, who
+likes her coffee hot:
+
+<!-- @aliceOverlay @test -->
+```
+mkdir -p $DEMO_HOME/breakfast/overlays/alice
+
+cat <<EOF >$DEMO_HOME/breakfast/overlays/alice/kustomization.yaml
+commonLabels:
+  who: alice
+bases:
+- ../../base
+patches:
+- temperature.yaml
+EOF
+
+cat <<EOF >$DEMO_HOME/breakfast/overlays/alice/temperature.yaml
+kind: Coffee
+metadata:
+  name: morningCup
+temperature: hot!
+EOF
+```
+
+And likewise for Bob, who wants _five_ pancakes, with strawberries:
+
+<!-- @bobOverlay @test -->
+```
+mkdir -p $DEMO_HOME/breakfast/overlays/bob
+
+cat <<EOF >$DEMO_HOME/breakfast/overlays/bob/kustomization.yaml
+commonLabels:
+  who: bob
+bases:
+- ../../base
+patches:
+- 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:
+
+<!-- @generateAlice @test -->
+```
+kustomize build $DEMO_HOME/breakfast/overlays/alice
+```
+
+Likewise for Bob:
+
+<!-- @generateBob @test -->
+```
+kustomize build $DEMO_HOME/breakfast/overlays/bob
+```