mgrigoriev / kubernetes-rails-example

Rails → Kubernetes, using GitHub Actions

Rails app for experiments with deployment to Kubernetes cluster.

If you are going to use it for some purpose, please replace mgrigoriev/kubernetes-rails-example with a name of your docker image in all configuration files.

Configuration files

• Kubernetes
• GitHub Actions
• Scripts
• Dockerfile

K8s cluster setup

cd ~/.kube

# Add "do.yaml" config to existing "config" file
export KUBECONFIG=config:do.yaml

# See contexts for all clusters
kubectl config get-contexts

# Set current context
kubectl config use-context <context-name>

# Check if we are in the right context
kubectl get nodes

# Apply manifests
kubectl apply -R -f /path/to/app/.k8s/

# Create secret for pulling image from Docker registry
kubectl create secret docker-registry regcred --docker-server=registry-server> \
                                              --docker-username=<username> \
                                              --docker-password=<password> \
                                              --docker-email=<email>

# Create secrets for access to external database and redis server
kubectl create secret generic env --from-literal=DATABASE_URL=postgres://<user>:<pass>@<ip>:5432/<dbname> \
                                  --from-literal=REDIS_URL=redis://<ip>:6379/0

GitHub setup

Create secrets required for GitHub Actions:

• DOCKERHUB_USERNAME
• DOCKERHUB_TOKEN
• KUBE_CONFIG_DATA

Run this command to get a value for KUBE_CONFIG_DATA:

cat $HOME/.kube/<cluster-config> | base64

Notes for Minikube

1. Use host.minikube.internal instead of ip address in DATABASE_URL and REDIS_URL when Postgres and redis are running on a host machine.

2. Minikube requires manual action for load balancer service. After applying k8s manifests, run this command:

   minikube service kubernetes-rails-example-load-balancer -n <your-namespace>
   

Useful links

• Dockerize Rails, the lean way
• Deploying a Rails application to Kubernetes