rswrz / cldtr-tech-task

Tech Task

This chart contains a simple Kubernetes deployment of the container image https://gcr.io/google-samples/hello-app:2.0. The container image version (image tag) is defined with appVersion configuration in Chart.yaml and can be overwritten by the parameter image.tag.

The Kubernetes deployment creates per default 1 pod replica. This can be configured with the parameter replicaCount.

The Kubernetes pods are exposed by default with a Kubernetes service as type ClusterIP on port 80. The service will be kept when uninstalling the chart. This behavior and the service itself is configurable with parameters.

The chart creates per default a PersistentVolumeClaim to mount a PersistentVolume into the directory /persistent-data inside the container for persistent data storage. The usage of an persistent volume can be disabled by setting the parameter persistence.enabled to false during installation or upgrade.

Dependencies

This chart uses bitnami mysql as sub-chart (external dependency). Before running helm install or helm upgrade all dependencies have to be installed into ./charts directory by running helm dependency build.

The bitnami mysql chart needs some mandatory parameters. A list of all parameters is available in the Github repository.

⚠️ All parameters listed in the official bitnami mysql chart documentation have to be prefix with the sub-chart name mysql.

Because of the previously mentioned, the following parameters are mandatory for the tech-task chart:

Name	Description
mysql.auth.rootPassword	Password for the root user. Ignored if existing secret is provided
mysql.auth.password	Password for the new user. Ignored if existing secret is provided

Alternatively a external secret can be specified with mysql.auth.existingSecret. Please read MySQL common parameters for details.

The connection information is passed to the container by environment variables.

Environment Variable Name	Description
MYSQL_HOST	The database instance hostname (Kubernetes Service name; Only accessible inside the namespace)
MYSQL_DATABASE	The database name
MYSQL_USERNAME	The database username
MYSQL_PASSWORD	The database usernames password

Quick start

To install the chart in a custom namespace run:

helm dependency build
helm install tech-task . \
    --create-namespace \
    --namespace tech-task \
    --set mysql.auth.rootPassword=root \
    --set mysql.auth.password=tech-task

Upgrade the installation:

helm upgrade tech-task . \
    --create-namespace \
    --namespace tech-task \
    --set mysql.auth.rootPassword=root \
    --set mysql.auth.password=tech-task

Uninstall the chart:

helm uninstall tech-task

Purge kept resources and persistent data:

kubectl --namespace tech-task delete svc/tech-task
kubectl --namespace tech-task delete pvc/tech-task

Parameters

Name	Description	Default Value
affinity	Affinity for application pods assignment	{}
containerEnv	Key-Value Map for application pods environment variables	{ _EXAMPLE_ENV_: Just a dummy for demonstration }
fullnameOverride	String to fully override tech-task.names.fullname template	""
image.pullPolicy	Application image pull policy	IfNotPresent
image.repository	Application image repository	gcr.io/google-samples/hello-app
image.tag	Application image tag (immutable tags are recommended)	"" - defaults to appVersion in Chart.yaml
imagePullSecrets	Specify docker-registry secret names as an array	[]
nameOverride	String to partially override tech-task.names.fullname template (will maintain the release name)	""
nodeSelector	Node labels for application pods assignment	{}
persistence.accessModes	Application persistent volume access Modes	[ ReadWriteOnce ]
persistence.enabled	Enable persistence on application replicas using a PersistentVolumeClaim. If false, use emptyDir	true
persistence.size	Application persistent volume size	10Gi
persistence.storageClass	Application persistent volume storage class. If undefined or empty use clusters default storage class.	""
podAnnotations	Additional pod annotations for application pods	{}
podSecurityContext	Application pods security context	{}
replicaCount	Number of application pod replicas	1
resources	The resources limits and requests for application containers	{}
securityContext	Application containers security context	{}
service.port	Application Kubernetes service port	80
service.preserve	Specifies if the Kubernetes service is kept during helm uninstall	true
service.type	Application Kubernetes service type	ClusterIP
serviceAccount.annotations	Annotations for application service account	{}
serviceAccount.create	Enable the creation of a ServiceAccount for application pods	true
serviceAccount.name	Name of the created ServiceAccount	""
tolerations	Tolerations for application pods assignment	[]
updateStrategy	Update strategy type for the application deployment. Set this to Recreate if a PV is used that cannot be mounted on multiple pods	{ type: RollingUpdate, rollingUpdate: {} }

Subchat Parameters

A list of all parameters for the mysql subchart is available in the Github repository of that chart.

⚠️ All parameters those parameters needs to be prefix with the chart name mysql.

These parameters are set per default in this chart:

Name	Description	Default Value
mysql.auth.database	Name for a custom database to create	tech-task
mysql.auth.username	Name for a custom user to create	tech-task