Using `kubectl`¶

Create ConfigMap from config files¶

A ConfigMap stores K8s-specific configuration that can be mounted as volume or used in env variables. It is often used to provide production configuration: application configuration, log settings, etc...

kubectl create configmap app-conf --from-file=<path to config files>  # create a ConfigMap from multiple files in the same directory.

Check the ConfigMap

kubectl get configmap app-conf -o yaml

# or

kubectl describe configmaps app-conf

Create a Kubernetes secret¶

You may need a Secret to store database passwords and secret keys.

For applications using the Play Framework, generate a secret using:

secretText = $(sbt playGenerateSecret)
regex = "Generated new secret: (.+)$"
f [[ $secretText =~ $regex ]]
    then
        secret = "${BASH_REMATCH[1]}"
        echo $secret
        kubectl create secret generic application-secret --from-literal=application_secret=$secret
        kubectl get secrets
    else
        echo "$secretText doesn't match" >&2
    fi
done

Create Resources (Deployment, Service, Ingress, etc...)¶

kubectl create -f <path/to/resource_config.yaml>

Verify proper resource creation

kubectl get ing
kubectl get service
kubectl get deployment
kubectl get pods

To delete a resource later, in this case a Deployment:

kubectl delete deployment <deployment name>

Install an Ingress Controller¶

An ingress controller is necessary to make Ingresses work. See the Ingress doc

Minikube¶

minikube provides its own ingress controller via the Ingress add-on:

minikube addons enable ingress

Enabling the add-on provisions the following:

a configMap for the Nginx loadbalancer
the Nginx ingress controller
a service that exposes a default Nginx backend pod for handling unmapped requests.

Alternative ingress controllers¶

Install https://traefik.io/

Declarative Deployments (Kustomize)¶

Kustomize is built into kubectl and allows for template-free customization of YAML manifests.

To deploy a directory containing a kustomization.yaml file:

kubectl apply -k <directory-path>

To view the generated native manifests without applying them:

kubectl kustomize <directory-path>

Using kubectl¶