carvel-ytt.md

Define And Deploy The App To Dev With Carvel ytt

ytt templates are plain YAML documents made from nodes - for example, maps and arrays. ytt allows you to set values and use programming logic (such as if statements and for loops) on those nodes. This eliminates text insertion concerns like manual escaping and allows for easy structure reuse.

To get a feel for how ytt works, you can play with it in the interactive playground. There are examples there (organized by topic) so that you can familiarize yourself with ytt's key features.

Finally, ytt guarantees that templates produce identical output with the same inputs. This works because the ytt execution environment is airtight and protected from outside influences, with no access to the filesystem, network, time, randomness, or operating system interfaces.

Setup

• Install the ytt CLI

chmod +x manuscript/define-deploy-dev/carvel-ytt.sh

./manuscript/define-deploy-dev/carvel-ytt.sh

Do

ls -1 ytt/resources

cat ytt/resources/deployment.yaml

cat ytt/resources/service.yaml

cat ytt/resources/ingress.yaml

cat ytt/schema.yaml

cat ytt/values-dev.yaml

yq --inplace ".image.tag = \"$TAG\"" ytt/values-dev.yaml

cat ytt/values-dev.yaml

ytt --file ytt/schema.yaml --file ytt/resources \
    --data-values-file ytt/values-dev.yaml \
    | tee yaml/dev/app.yaml

kubectl --namespace dev apply --filename yaml/dev

echo "http://cncf-demo-dev.$DOMAIN"

# Open it in a browser

• If you chose kbld to build images, then with one command you can use kbld to build the images, push them to a registry, and modify the manifests with image SHAs. Next use kubectl to apply the manifests generated by kbld.

Continue The Adventure

• Use HTTPS