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Creating a Kubernetes Cluster for Elafros

Two options:

Setup a GKE cluster
Run minikube locally

GKE

To use a k8s cluster running in GKE:

Install gcloud using the instructions for your platform.
Create a GCP project (or use an existing project if you've already created one) at http://console.cloud.google.com/home/dashboard. Set the ID of the project in an environment variable (e.g. PROJECT_ID).

If you are a new GCP user, you might be eligible for a trial credit making your GKE cluster and other resources free for a short time. Otherwise, any GCP resources you create will cost money.

Enable the k8s API:

gcloud --project=$PROJECT_ID services enable container.googleapis.com

Create a k8s cluster (version 1.9 or greater):
```
gcloud --project=$PROJECT_ID container clusters create \
  --cluster-version=1.9.6-gke.1 \
  --zone=us-east1-d \
  --scopes=cloud-platform \
  --machine-type=n1-standard-4 \
  --enable-autoscaling --min-nodes=1 --max-nodes=3 \
  elafros-demo
```
- Version 1.9+ is required
- Change this to whichever zone you choose
- cloud-platform scope is required to access GCB
- Elafros currently requires 4-cpu nodes to run conformance tests. Changing the machine type from the default may cause failures.
- Autoscale from 1 to 3 nodes. Adjust this for your use case
- Change this to your preferred cluster name
You can see the list of supported cluster versions in a particular zone by running:
```
# Get the list of valid versions in us-east1-d
gcloud container get-server-config --zone us-east1-d
```
If you haven't installed kubectl yet, you can install it now with gcloud:
```
gcloud components install kubectl
```

Add to your .bashrc:

# When using GKE, the K8s user is your GCP user.
export K8S_USER_OVERRIDE=$(gcloud config get-value core/account)

Minikube

Install and configure minikube with a VM driver, e.g. kvm2 on Linux or hyperkit on macOS.
Create a cluster with version 1.9 or greater and your chosen VM driver:

Until minikube enables it by default,the MutatingAdmissionWebhook plugin must be manually enabled.

Until minikube makes this the default, the certificate controller must be told where to find the cluster CA certs on the VM.

Starting with v0.26.0 minikube defaults to the kubeadm bootstrapper, so we need to explicitly set the bootstrapper to be localkube for our extra-config settings to work.

For Linux use:

minikube start \
  --kubernetes-version=v1.9.4 \
  --vm-driver=kvm2 \
  --bootstrapper=localkube \
  --extra-config=apiserver.Admission.PluginNames=DenyEscalatingExec,LimitRanger,NamespaceExists,NamespaceLifecycle,ResourceQuota,ServiceAccount,DefaultStorageClass,MutatingAdmissionWebhook \
  --extra-config=controller-manager.ClusterSigningCertFile="/var/lib/localkube/certs/ca.crt" \
  --extra-config=controller-manager.ClusterSigningKeyFile="/var/lib/localkube/certs/ca.key"

For macOS use:

minikube start \
  --kubernetes-version=v1.9.4 \
  --vm-driver=hyperkit \
  --bootstrapper=localkube \
  --extra-config=apiserver.Admission.PluginNames=DenyEscalatingExec,LimitRanger,NamespaceExists,NamespaceLifecycle,ResourceQuota,ServiceAccount,DefaultStorageClass,MutatingAdmissionWebhook \
  --extra-config=controller-manager.ClusterSigningCertFile="/var/lib/localkube/certs/ca.crt" \
  --extra-config=controller-manager.ClusterSigningKeyFile="/var/lib/localkube/certs/ca.key"

Minikube with GCR

You can use Google Container Registry as the registry for a Minikube cluster.

Set up a GCR repo. Export the environment variable PROJECT_ID as the name of your project. Also export GCR_DOMAIN as the domain name of your GCR repo. This will be either gcr.io or a region-specific variant like us.gcr.io.
```
export PROJECT_ID=elafros-demo-project
export GCR_DOMAIN=gcr.io
```
To publish builds push to GCR, set KO_DOCKER_REPO or DOCKER_REPO_OVERRIDE to the GCR repo's url.
```
export KO_DOCKER_REPO="${GCR_DOMAIN}/${PROJECT_ID}"
export DOCKER_REPO_OVERRIDE="${KO_DOCKER_REPO}"
```

Create a GCP service account:

gcloud iam service-accounts create minikube-gcr \
  --display-name "Minikube GCR Pull" \
  --project $PROJECT_ID

Give your service account the storage.objectViewer role:

gcloud projects add-iam-policy-binding $PROJECT_ID \
  --member "serviceAccount:minikube-gcr@${PROJECT_ID}.iam.gserviceaccount.com" \
  --role roles/storage.objectViewer

Create a key credential file for the service account:

gcloud iam service-accounts keys create \
  --iam-account "minikube-gcr@${PROJECT_ID}.iam.gserviceaccount.com" \
  minikube-gcr-key.json

Now you can use the minikube-gcr-key.json file to create image pull secrets and link them to Kubernetes service accounts. A secret must be created and linked to a service account in each namespace that will pull images from GCR.

For example, use these steps to allow Minikube to pull Elafros and Build images from GCR as published in our development flow (ko apply -f config/). This is only necessary if you are not using public Elafros and Build images.

Create a Kubernetes secret in the ela-system and build-system namespace:

for prefix in ela build; do
  kubectl create secret docker-registry "gcr" \
    --docker-server=$GCR_DOMAIN \
    --docker-username=_json_key \
    --docker-password="$(cat minikube-gcr-key.json)" \
    --docker-email=your.email@here.com \
    -n "${prefix}-system"
done

The secret must be created in the same namespace as the pod or service account.

Add the secret as an imagePullSecret to the ela-controller and build-controller service accounts:

for prefix in ela build; do
  kubectl patch serviceaccount "${prefix}-controller" \
    -p '{"imagePullSecrets": [{"name": "gcr"}]}' \
    -n "${prefix}-system"
done

Add to your .bashrc:

# When using Minikube, the K8s user is your local user.
export K8S_USER_OVERRIDE=$USER

Use the same procedure to add imagePullSecrets to service accounts in any namespace. Use the default service account for pods that do not specify a service account.

See also the private-repo sample README.

7.0 KiB Raw Blame History

Creating a Kubernetes Cluster for Elafros

GKE

Minikube

Minikube with GCR

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