common-app

common-app is a unified chart template for deploy services with CI/CD.

TL;DR

$ helm repo add petrel-ai https://balzhik95.github.io/common-app/charts
$ helm repo update
$ helm install my-release petrel-ai/common-app --set image.repository=<Hostname of your container registry> --set image.tag=<tag of your container image>

Prerequisites

• Kubernetes 1.12+
• Helm 3.1.0

Installing the Chart

To install the chart with the release name my-release:

$ helm install my-release petrel-ai/common-app \
  --set image.repository=<Hostname of your container registry> \
  --set image.tag=<Tag of your container image>

These commands deploy service on the Kubernetes cluster in the default configuration. The Parameters section lists the parameters that can be configured during installation.

Tip: List all releases using helm list

Parameters

Global parameters

Name	Description	Value
global.imagePullSecrets	Global Docker registry secret names as an array	[]
global.storageClass	Global StorageClass for Persistent Volume(s)	nil

Common parameters

Name	Description	Value
kubeVersion	Force target Kubernetes version (using Helm capabilities if not set)	nil
nameOverride	String to partially override service.fullname template with a string (will prepend the release name)	nil
fullnameOverride	String to fully override service.fullname template with a string	nil

app parameters

Name	Description	Value
image.registry	App image registry	nil
image.repository	App image repository	nil
image.tag	App image tag (immutable tags are recommended)	nil
image.pullPolicy	App image pull policy	Always
replicaCount	Number of replicas of the app Pod	1
updateStrategy.type	Set up update strategy for app installation.	RollingUpdate
hostAliases	Add deployment host aliases	[]
env	env vars to configure app	nil
envSecret	Enable/Disabke ingest from secret containing extra env vars to configure app (in case of sensitive data)	false
extraVolumes	Array to add extra volumes. Requires setting extraVolumeMounts	nil
extraVolumeMounts	Array to add extra mounts. Normally used with extraVolumes	nil
livenessProbe	Liveness probe	nil
readinessProbe	Readiness probe	nil
service.port	Kubernetes Service port	8080
service.type	Kubernetes Service type	ClusterIP
service.nodePort	Specify the nodePort value for the LoadBalancer and NodePort service types	nil
service.externalTrafficPolicy	Enable client source IP preservation	Cluster
service.loadBalancerIP	loadBalancerIP if app service type is LoadBalancer	nil
service.extraPorts	Extra ports to expose in the service (normally used with the sidecar value)	nil
ingress.enabled	Enable ingress controller resource	false
ingress.certManager	Add annotations for cert-manager	false
ingress.pathType	Ingress Path type	ImplementationSpecific
ingress.path	The Path to app. You may need to set this to '/*' in order to use this with ALB ingress controllers.	ImplementationSpecific
ingress.annotations	Ingress annotations	{}
ingress.tls.secretName	TLS secret	false
ingress.tls.hosts	TLS host	false
ingress.extraHosts	The list of additional hostnames to be covered with this ingress record.	[]
ingress.extraPaths	Additional arbitrary path/backend objects	[]
ingress.extraTls	The tls configuration for additional hostnames to be covered with this ingress record.	[]
containerPort	Port to expose at container level	8080
resources.limits	The resources limits for the container	{}
resources.requests	The requested resources for the container	{}
affinity	Affinity for pod assignment	{}
nodeSelector	Node labels for pod assignment	{}
tolerations	Tolerations for pod assignment	[]
sidecars	Additional containers to run within the same pod	nil
initContainers	Temporary init containers to run before main container up	nil

Alternatively, a YAML file that specifies the values for the parameters can be provided while installing the chart. For example,

$ helm install my-release -f values.yaml common-app/

Tip: You can use the default values.yaml

Configuration and installation details

It is strongly recommended to use immutable tags in a production environment. This ensures your deployment does not change automatically if the same tag is updated with a different image.

How to use environment variables

In case you want to add environment variables, you can use the env property.

env:
  ELASTICSEARCH_VERSION: 6
  LOG_LEVEL: debug

How to use secret environment variables

Alternatively, you can use a a Secret with the environment variables. To do so, use the envSecret values.

envSecret: true

Then you enable this parameter (by default it's = false), your deployment will mount all data variables from secret in the same namespace. So before deploy application, you must to create application secret with variables. Secret name must be {{ service.fullname }}.

Sidecars and Init Containers

If you have a need for additional containers to run within the same pod as app (e.g. an additional metrics or logging exporter), you can do so via the sidecars config parameter. Simply define your container according to the Kubernetes container spec.

sidecars:
- name: your-image-name
  image: your-image
  imagePullPolicy: Always
  ports:
  - name: portname
    containerPort: 1234

Similarly, you can add extra init containers using the initContainers parameter.

initContainers:
- name: your-image-name
  image: your-image
  imagePullPolicy: Always
  ports:
  - name: portname
    containerPort: 1234

Adding extra volumes

The common-app chart supports mounting extra volumes (either PVCs, secrets or configmaps) by using the extraVolumes and extraVolumeMounts property. This can be combined with advanced operations like adding extra init containers and sidecars.