How to convert k8s yaml to helm chart - kubernetes

Question

Right now I'm deploying applications on k8s using yaml files.
Like the one below:
apiVersion: v1
kind: Service
metadata:
name: serviceA
namespace: flow
spec:
ports:
- port: 8080
targetPort: 8080
selector:
app: serviceA
---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: serviceA-ingress
namespace: flow
annotations:
nginx.ingress.kubernetes.io/use-regex: "true"
kubernetes.io/ingress.class: nginx
certmanager.k8s.io/cluster-issuer: letsencrypt-prod
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
tls:
- hosts:
- serviceA.xyz.com
secretName: letsencrypt-prod
rules:
- host: serviceA.xyz.com
http:
paths:
- path: /
backend:
serviceName: serviceA
servicePort: 8080
---
apiVersion: v1
kind: ConfigMap
metadata:
name: serviceA-config
namespace: flow
data:
application-dev.properties: |
spring.application.name=serviceA-main
server.port=8080
logging.level.org.springframework.jdbc.core=debug
lead.pg.url=serviceB.flow.svc:8080/lead
task.pg.url=serviceB.flow.svc:8080/task
---
apiVersion: apps/v1 # for versions before 1.9.0 use apps/v1beta2
kind: Deployment
metadata:
name: serviceA-deployment
namespace: flow
spec:
selector:
matchLabels:
app: serviceA
replicas: 1 # tells deployment to run 2 pods matching the template
template:
metadata:
labels:
app: serviceA
spec:
containers:
- name: serviceA
image: xyzaccount.dkr.ecr.eu-west-1.amazonaws.com/flow/test:serviceA-v1
command: [ "java", "-jar", "-agentlib:jdwp=transport=dt_socket,address=9098,server=y,suspend=n", "serviceA-service.jar", "--spring.config.additional-location=/config/application-dev.properties" ]
ports:
- containerPort: 8080
volumeMounts:
- name: serviceA-application-config
mountPath: "/config"
readOnly: true
volumes:
- name: serviceA-application-config
configMap:
name: serviceA-config
items:
- key: application-dev.properties
path: application-dev.properties
restartPolicy: Always
Is there any automated way to convert this yaml into helm charts.
Or any other workaround or sample template that I can use to achieve this.
Even if there is no any generic way, then I would like to know how to convert this specific yaml into helm chart.
Also want to know what all things should I keep configurable (I mean convert into variables) as I can't just put these resource in yaml into separate template folder and called it helm chart.

Answer 1

At heart a Helm chart is still just YAML so to make that a chart, just drop that file under templates/ and add a Chart.yml.

Answer 2

There is no unambiguous way to map k8s YAML to a Helm chart. Because app/chart maintainer should decide:
which app parameters can be modified by chart users
which of these parameters are mandatory
what are default values, etc...
So creation of a Helm chart is a manual process. But it contains a lot of routine steps. For example, most of the chart creators want to:
remove the namespace from templates to set it with helm install -n
remove fields generated by k8s
add helm release name to resource name
preserve correct links between templated names
move some obvious parameters to values.yaml like:
container resources
service type and ports
configmap/secret values
image repo:tag
I've created a CLI called helmify to automate the steps listed above.
It reads a list of k8s objects from stdin and creates a helm chart from it.
You can install it with brew brew install arttor/tap/helmify. And then use to generate charts from YAML file:
cat my-app.yaml | helmify mychart
or from directory <my_directory> containing yamls:
awk 'FNR==1 && NR!=1 {print "---"}{print}' /<my_directory>/*.yaml | helmify mychart
Both of the commands will create mychart Helm chart directory from your k8s objects similar to helm create command.
Here is a chart generated by helmify from the yaml published in the question:
mychart
├── Chart.yaml
├── templates
│   ├── _helpers.tpl
│   ├── config.yaml
│   ├── deployment.yaml
│   ├── ingress.yaml
│   └── serviceA.yaml
└── values.yaml
#values.yaml
config:
applicationDevProperties:
lead:
pg:
url: serviceB.flow.svc:8080/lead
logging:
level:
org:
springframework:
jdbc:
core: debug
server:
port: "8080"
spring:
application:
name: serviceA-main
task:
pg:
url: serviceB.flow.svc:8080/task
deployment:
replicas: 1
image:
serviceA:
repository: xyzaccount.dkr.ecr.eu-west-1.amazonaws.com/flow/test
tag: serviceA-v1
serviceA:
ports:
- port: 8080
targetPort: 8080
type: ClusterIP
---
# templates/config.yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: {{ include "mychart.fullname" . }}-config
labels:
{{- include "mychart.labels" . | nindent 4 }}
data:
application-dev.properties: |
spring.application.name={{ .Values.config.applicationDevProperties.spring.application.name | quote }}
server.port={{ .Values.config.applicationDevProperties.server.port | quote }}
logging.level.org.springframework.jdbc.core={{ .Values.config.applicationDevProperties.logging.level.org.springframework.jdbc.core | quote }}
lead.pg.url={{ .Values.config.applicationDevProperties.lead.pg.url | quote }}
task.pg.url={{ .Values.config.applicationDevProperties.task.pg.url | quote }}
---
# templates/deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: {{ include "mychart.fullname" . }}-deployment
labels:
{{- include "mychart.labels" . | nindent 4 }}
spec:
replicas: {{ .Values.deployment.replicas }}
selector:
matchLabels:
app: serviceA
{{- include "mychart.selectorLabels" . | nindent 6 }}
template:
metadata:
labels:
app: serviceA
{{- include "mychart.selectorLabels" . | nindent 8 }}
spec:
containers:
- command:
- java
- -jar
- -agentlib:jdwp=transport=dt_socket,address=9098,server=y,suspend=n
- serviceA-service.jar
- --spring.config.additional-location=/config/application-dev.properties
image: {{ .Values.image.serviceA.repository }}:{{ .Values.image.serviceA.tag |
default .Chart.AppVersion }}
name: serviceA
ports:
- containerPort: 8080
resources: {}
volumeMounts:
- mountPath: /config
name: serviceA-application-config
readOnly: true
restartPolicy: Always
volumes:
- configMap:
items:
- key: application-dev.properties
path: application-dev.properties
name: {{ include "mychart.fullname" . }}-config
name: serviceA-application-config
---
# templates/ingress.yaml
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: {{ include "mychart.fullname" . }}-ingress
labels:
{{- include "mychart.labels" . | nindent 4 }}
annotations:
certmanager.k8s.io/cluster-issuer: letsencrypt-prod
kubernetes.io/ingress.class: nginx
nginx.ingress.kubernetes.io/rewrite-target: /
nginx.ingress.kubernetes.io/use-regex: "true"
spec:
rules:
- host: serviceA.xyz.com
http:
paths:
- backend:
serviceName: serviceA
servicePort: 8080
path: /
tls:
- hosts:
- serviceA.xyz.com
secretName: letsencrypt-prod
---
# templates/serviceA.yaml
apiVersion: v1
kind: Service
metadata:
name: {{ include "mychart.fullname" . }}-serviceA
labels:
{{- include "mychart.labels" . | nindent 4 }}
spec:
type: {{ .Values.serviceA.type }}
selector:
app: serviceA
{{- include "mychart.selectorLabels" . | nindent 4 }}
ports:
{{- .Values.serviceA.ports | toYaml | nindent 2 -}}

Answer 3

https://github.com/mailchannels/palinurus/tree/master
This git repo contains a python script which will convert basic yamls to helm charts

Answer 4

You can use this tools, helmtrans : https://github.com/codeandcode0x/helmtrans . It can transform YAML to Helm Charts automation.
example:
➜ helmtrans yamltohelm -p [source path] -o [output path]