Meteor on Kubernetes ==================== This example shows you how to package and run a [Meteor](https://www.meteor.com/) app on Kubernetes. Get started on Google Compute Engine ------------------------------------ Meteor uses MongoDB, and we will use the `GCEPersistentDisk` type of volume for persistent storage. Therefore, this example is only applicable to [Google Compute Engine](https://cloud.google.com/compute/). Take a look at the [volumes documentation](../../docs/user-guide/volumes.md) for other options. First, if you have not already done so: 1. [Create](https://cloud.google.com/compute/docs/quickstart) a [Google Cloud Platform](https://cloud.google.com/) project. 2. [Enable billing](https://developers.google.com/console/help/new/#billing). 3. Install the [gcloud SDK](https://cloud.google.com/sdk/). Authenticate with gcloud and set the gcloud default project name to point to the project you want to use for your Kubernetes cluster: ```sh gcloud auth login gcloud config set project ``` Next, start up a Kubernetes cluster: ```sh wget -q -O - https://get.k8s.io | bash ``` Please see the [Google Compute Engine getting started guide](../../docs/getting-started-guides/gce.md) for full details and other options for starting a cluster. Build a container for your Meteor app ------------------------------------- To be able to run your Meteor app on Kubernetes you need to build a Docker container for it first. To do that you need to install [Docker](https://www.docker.com) Once you have that you need to add 2 files to your existing Meteor project `Dockerfile` and `.dockerignore`. `Dockerfile` should contain the below lines. You should replace the `ROOT_URL` with the actual hostname of your app. ``` FROM chees/meteor-kubernetes ENV ROOT_URL http://myawesomeapp.com ``` The `.dockerignore` file should contain the below lines. This tells Docker to ignore the files on those directories when it's building your container. ``` .meteor/local packages/*/.build* ``` You can see an example meteor project already set up at: [meteor-gke-example](https://github.com/Q42/meteor-gke-example). Feel free to use this app for this example. > Note: The next step will not work if you have added mobile platforms > to your meteor project. Check with `meteor list-platforms` Now you can build your container by running this in your Meteor project directory: ``` docker build -t my-meteor . ``` Pushing to a registry --------------------- For the [Docker Hub](https://hub.docker.com/), tag your app image with your username and push to the Hub with the below commands. Replace `` with your Hub username. ``` docker tag my-meteor /my-meteor docker push /my-meteor ``` For [Google Container Registry](https://cloud.google.com/tools/container-registry/), tag your app image with your project ID, and push to GCR. Replace `` with your project ID. ``` docker tag my-meteor gcr.io//my-meteor gcloud docker -- push gcr.io//my-meteor ``` Running ------- Now that you have containerized your Meteor app it's time to set up your cluster. Edit [`meteor-controller.json`](meteor-controller.json) and make sure the `image:` points to the container you just pushed to the Docker Hub or GCR. We will need to provide MongoDB a persistent Kubernetes volume to store its data. See the [volumes documentation](../../docs/user-guide/volumes.md) for options. We're going to use Google Compute Engine persistent disks. Create the MongoDB disk by running: ``` gcloud compute disks create --size=200GB mongo-disk ``` Now you can start Mongo using that disk: ``` kubectl create -f examples/meteor/mongo-pod.json kubectl create -f examples/meteor/mongo-service.json ``` Wait until Mongo is started completely and then start up your Meteor app: ``` kubectl create -f examples/meteor/meteor-service.json kubectl create -f examples/meteor/meteor-controller.json ``` Note that [`meteor-service.json`](meteor-service.json) creates a load balancer, so your app should be available through the IP of that load balancer once the Meteor pods are started. We also created the service before creating the rc to aid the scheduler in placing pods, as the scheduler ranks pod placement according to service anti-affinity (among other things). You can find the IP of your load balancer by running: ``` kubectl get service meteor --template="{{range .status.loadBalancer.ingress}} {{.ip}} {{end}}" ``` You will have to open up port 80 if it's not open yet in your environment. On Google Compute Engine, you may run the below command. ``` gcloud compute firewall-rules create meteor-80 --allow=tcp:80 --target-tags kubernetes-node ``` What is going on? ----------------- Firstly, the `FROM chees/meteor-kubernetes` line in your `Dockerfile` specifies the base image for your Meteor app. The code for that image is located in the `dockerbase/` subdirectory. Open up the `Dockerfile` to get an insight of what happens during the `docker build` step. The image is based on the Node.js official image. It then installs Meteor and copies in your apps' code. The last line specifies what happens when your app container is run. ```sh ENTRYPOINT MONGO_URL=mongodb://$MONGO_SERVICE_HOST:$MONGO_SERVICE_PORT /usr/local/bin/node main.js ``` Here we can see the MongoDB host and port information being passed into the Meteor app. The `MONGO_SERVICE...` environment variables are set by Kubernetes, and point to the service named `mongo` specified in [`mongo-service.json`](mongo-service.json). See the [environment documentation](../../docs/user-guide/container-environment.md) for more details. As you may know, Meteor uses long lasting connections, and requires _sticky sessions_. With Kubernetes you can scale out your app easily with session affinity. The [`meteor-service.json`](meteor-service.json) file contains `"sessionAffinity": "ClientIP"`, which provides this for us. See the [service documentation](../../docs/user-guide/services.md#virtual-ips-and-service-proxies) for more information. As mentioned above, the mongo container uses a volume which is mapped to a persistent disk by Kubernetes. In [`mongo-pod.json`](mongo-pod.json) the container section specifies the volume: ```json { "volumeMounts": [ { "name": "mongo-disk", "mountPath": "/data/db" } ``` The name `mongo-disk` refers to the volume specified outside the container section: ```json { "volumes": [ { "name": "mongo-disk", "gcePersistentDisk": { "pdName": "mongo-disk", "fsType": "ext4" } } ], ``` [![Analytics](https://kubernetes-site.appspot.com/UA-36037335-10/GitHub/examples/meteor/README.md?pixel)]()