Helm

Notes

• Works like a wrapper around Kubernetes clusters. Has its own artifact repository, you can pull charts and change them similar to docker

• Prefixing a file with _ makes helm ignore the helper file

Charts

Values

• Templates are basically the Kubernetes services and deployments.

apiVersion: v1 kind: Service metadata:
name: {{•Release.Name }}-svc
spec:
type: NodePort ports:
- port: 80
targetPort: http protocol: TCP
name: http selector:
app: hello-world

apiVersion: apps/v1
kind: Deployment metadata:
name:
{{•Release. Name }}-nginx
spec:
replicas: 2 selector:
matchLabels:
app: hello-world template:
metadata: labels:
app: hello-world spec:
containers:
- name: hello-world image: nginx ports:
- name: http containerPort:
80
protocol: TCP

• {{ Release.Name }} is basically Go templating

• If the values are empty their template value will be empty

• You can create a values.yaml file and in that you can define dictionaries for making the namings easier:

replicaCount: 2
image:
repository: nginx 
pullPolicy: IfNotPresent
tag: "1.16.0"

In this case you can just say {{Values.repository}}

• helm lint ./nginx-chart is linting the chart same as Terraform does it

Functions

• Same as Terraform functions: string, security, kubernetes, regex, etc.

• Common string functions are: upper, quote, replace x,y,z, default

• You can also use pipeline for combining functions, e.g. {‹ • Values image.repository | upper | quote| shuffle }} => resulting in image: GN"XNI"

Links