OAM Kubernetes Runtime

The plug-in for implementing Open Application Model (OAM) control plane with Kubernetes.

🚨 NOTE: this project is designed as low level dependency for building end-to-end implementation of OAM (i.e. KubeVela). Do not play with it unless you know what you are doing. 🚨

Prerequisites

• Kubernetes v1.16+
• Helm 3

OAM Runtime Release	Supported Spec Release	Comments
Latest release	OAM Spec v0.2.1

Installation

1. Create namespace for OAM runtime controller

kubectl create namespace oam-system

2. Add helm repo

helm repo add crossplane-master https://charts.crossplane.io/master/

3. Install OAM Kubernetes Runtime

Install with webhook enabled by following steps:

• Step 1: Admission Webhook need you to prepare certificates and ca for production use. For none-production use, you could generate them by running the shell script provided in repo.

  curl -sfL https://raw.githubusercontent.com/crossplane/oam-kubernetes-runtime/master/hack/ssl/ssl.sh | bash -s oam-kubernetes-runtime-webhook oam-system

  The shell will generate files like below:

  $ tree
  .
  ├── csr.conf
  ├── oam-kubernetes-runtime-webhook.csr
  ├── oam-kubernetes-runtime-webhook.key
  └── oam-kubernetes-runtime-webhook.pem
  
  0 directories, 4 files

• Step 2: Create secret for ssl certificates:

  • Notice the server key and certificate must be named tls.key and tls.crt, respectively.
  • Secret name can be user defined, we'd better align with chart values.

  kubectl -n oam-system create secret generic webhook-server-cert --from-file=tls.key=./oam-kubernetes-runtime-webhook.key --from-file=tls.crt=./oam-kubernetes-runtime-webhook.pem

• Step 3: Get CA Bundle info and install with its value

  caValue=`kubectl config view --raw --minify --flatten -o jsonpath='{.clusters[].cluster.certificate-authority-data}'`
  helm install core-runtime -n oam-system ./charts/oam-kubernetes-runtime --set useWebhook=true --set certificate.caBundle=$caValue 

For quick developing purpose only:

You can install this lib without webhook by:

helm install oam --namespace oam-system crossplane-master/oam-kubernetes-runtime --devel

But be aware that in this case, you will lose critical validations and injections required by OAM control plane. Only do this when you know what you are doing.

Verify the Installation

• We have some examples in the repo for you to verify the OAM control plane is working:

  git clone git@github.com:crossplane/oam-kubernetes-runtime.git	
  cd ./oam-kubernetes-runtime	

• Apply a sample application configuration

  kubectl apply -f examples/containerized-workload

• Verify that the application is running

  Check its components:

  kubectl get components
  NAME                WORKLOAD-KIND           AGE
  example-component   ContainerizedWorkload   63s

  Check its application configuration:

  kubectl get appconfig
  NAME                AGE
  example-appconfig   3m48s

  Check the status and events from the application

  kubectl describe appconfig example-appconfig
  Status:
    Conditions:
      Last Transition Time:  2020-06-12T21:18:40Z
      Reason:                Successfully reconciled resource
      Status:                True
      Type:                  Synced
    Workloads:
      Component Name:  example-component
      Traits:
        Trait Ref:
          API Version:  core.oam.dev/v1alpha2
          Kind:         ManualScalerTrait
          Name:         example-appconfig-trait
      Workload Ref:
        API Version:  core.oam.dev/v1alpha2
        Kind:         ContainerizedWorkload
        Name:         example-appconfig-workload
  Events:
    Type    Reason                 Age              From                                       Message
    ----    ------                 ----             ----                                       -------
    Normal  RenderedComponents     6s (x2 over 7s)  oam/applicationconfiguration.core.oam.dev  Successfully rendered components
    Normal  AppliedComponents      6s (x2 over 6s)  oam/applicationconfiguration.core.oam.dev  Successfully applied components
    Normal  Deployment created     6s (x3 over 6s)  ContainerizedWorkload                      Workload `example-appconfig-workload` successfully server side patched a deployment `example-appconfig-workload`
    Normal  Service created        6s (x3 over 6s)  ContainerizedWorkload                      Workload `example-appconfig-workload` successfully server side patched a service `example-appconfig-workload`
    Normal  Manual scalar applied  6s (x2 over 6s)  ManualScalarTrait                          Trait `example-appconfig-trait` successfully scaled a resouce to 3 instances
  

  You should also check underlying deployment and service looking like below

  kubectl get deployments
  NAME                                    READY   UP-TO-DATE   AVAILABLE   AGE
  example-appconfig-workload-deployment   3/3   3           3              28s

  kubectl get services
  AME                                             TYPE       CLUSTER-IP     EXTERNAL-IP   PORT(S)    AGE
  example-appconfig-workload-deployment-service   NodePort   10.96.78.215   <none>        8080/TCP   28s

Cleanup

helm uninstall oam -n oam-system
kubectl delete -f examples/containerized-workload
kubectl delete namespace oam-system --wait

Want to help?

Check out DEVELOPMENT.md to see how to develop with OAM Kubernetes runtime

Licenses

The OAM Kubernetes runtime is released under the Apache 2.0 license.