chart-flex

A flexible Helm chart that is useful for developers to easily deploy various software using a single chart; the objective is to cater for different types of workloads.

But, really, its handy for anyone wanting to quickly deploy an arbitrary workload.

Overview

An attempt to cover the main workload resources in one chart:

• Deployment
• ReplicaSet
• StatefulSet
• DaemonSet
• Job
• CronJob

TODO:

• look at ReplicationController
• make the NOTES.txt and _helpers.tpl work nicely based on chosen workload type(s)
• tests with terratest
• make jobs an array like cronjobs without boolean toggle
• support multiple containers in the deployment pod besides init containers

Prerequisites

• Kubernetes >= 1.19.0
• Helm >= 3.0.0

Usage

You can use the chart directly and override the image etc. though typically you would make a copy and edit.

Values Reference

The following table lists the configurable parameters of the flex chart and the default values.

Parameter	Description	Default
affinity		{}
autoscaling.enabled		false
autoscaling.minReplicas		1
autoscaling/maxReplicas		100
autoscaling.targetCPUUtilizationPercentage		80
autoscaling.targetMemoryUtilizationPercentage
cronjob.enabled		false
daemonset.enabled		false
deployment.enabled		true
fullnameOverride
global.environment		[]
imagePullSecrets		[]
image.pullPolicy		IfNotPresent
image.repository		nginx
image.tag		stable
ingress.enabled		false
ingress.className
ingress.annotations		{}
ingress.hosts		[{ host: chart-example.local, paths: [{ path: /, pathType: ImplementationSpecific }] }]
ingress.tls		[]
initContainers	Init containers to add to the deployment	[]
job.enabled		false
job.restartPolicy		OnFailure
nameOverride
nodeSelector		{}
podAnnotations		{}
podSecurityContext		{}
replicaCount		1
replicaset.enabled		false
resources		{}
securityContext		{}
serviceAccount.annotations	Annotations to add to the service account	{}
serviceAccount.create	Specifies whether a service account should be created	true
serviceAccount.name	The name of the service account to use. If not set and create is true, a name is generated using the fullname template
service.port		80
service.type		ClusterIP
statefulset.enabled		false
tolerations		[]

Quick Guide

Validate the chart:

helm lint .

Dry run and print out rendered YAML:

helm install --dry-run --debug flex .

Dry run and print out rendered YAML with merged values file:

helm install \
--dry-run \
--debug \
-f helm-values.local.yaml \
flex .

Installation

helm install flex .

Or, with some different values:

helm install flex \
--set image.tag="latest" \
--set service.type="LoadBalancer" \
.

Or, the same but with a custom values from a file:

helm install flex \
-f helm-values.local.yaml \
.

Testing

Testing after creation of a release:

helm test flex

Upgrading

Upgrade the chart, with values file:

helm upgrade flex . \
-f helm-values.local.yaml

Uninstallation

Completely remove the chart:

helm uninstall flex

Workload Type Switching

Deployment

This is the default workload type. Set values as required, most of which are directly from helm create. To disable it (usually the case when using other workload type(s)), set the deployment.enabled value to false.

Example using ingress, service and load balancer:

deployment:
enabled: true
ingress:
enabled: true
className: nginx
hosts:
- host: flex.local
paths:
- path: /
pathType: Prefix
service:
enabled: true
type: LoadBalancer

ReplicaSet

Set replicaset.enabled to true.

StatefulSet

Set statefulset.enabled to true.

DaemonSet

Set daemonset.enabled to true.

Job

This is adapted from https://github.com/cetic/helm-job.

Disable the deployment, setup a job as required, e.g.:

deployment:
enabled: false
job:
enabled: true
image:
repository: "hello-world"
tag: "latest"

CronJob

This is adapated from https://github.com/bambash/helm-cronjobs.

Disable the deployment and set one or more cron jobs as required, e.g.:

deployment:
enabled: false
cronjobs:
- name: 'hello-world'
image:
repository: hello-world
tag: latest
imagePullPolicy: Always
schedule: "*/5 * * * *"
failedJobsHistoryLimit: 5
successfulJobsHistoryLimit: 100
concurrencyPolicy: Allow
restartPolicy: OnFailure

Contributing

Please feel free to contribute by making a pull request.

License

• Author: Chris Fordham (chris@fordham.id.au)

Copyright 2020, Chris Fordham
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.