.NET on GCP

samples provided as-is without warranty

Sample code demonstrating running trivial .NET web applications on Google Cloud Platform services.
These simply builds off of existing technologies and samples but configures it to run on GCP effeciently with healh checking and load balancing.

The example here uses Microsofts's .NET Core 1.0.0 RC/preview (dotnet-dev-1.0.0-preview2-003121).

microsoft/dotnet:1.1.0-sdk-projectjson

FROM microsoft/dotnet:1.1.0-sdk-projectjson

ADD . /app
WORKDIR /app
RUN ["dotnet", "restore"]

EXPOSE 8080
WORKDIR /app/src/WebApplication1/
ENTRYPOINT ["dotnet", "run", "-p", "project.json"]

in project.json:

"Microsoft.NETCore.App": {
   "type": "platform",
   "version": "1.1.0"
}

You can use Visutal Studio 2015 to create and extend the sample from scratch. VS2015

• WebApplication1 Default webapplication generated by Visual Studio 2015: "New Project
  • C#
    • Web
      • ASP.NET Core Web Application (.NET Core) ; (Change Authenticaiton --> No Authentication)

(optionally, if you want to try out Google APIs, see Using Google API Libraries)

The platforms that are demonstrated here are:

• Appengine
• ContainerEngine
• Container-Optimized OS

---

Basic Configuration

Sample application simply spins up inside a Docker container an runs Kestrel to host the application. The sample is modified from the baseline in the following way to run with healthchecks in GCP:

• port: 8080
• GET requests to endpoint /_ah/health must return a 200 OK HTTP response
• Use Kestrel Webserver

---

WebApplication1

To run the code directly from the source dockerhub image:

docker run -p 8080:8080 docker.io/salrashid123/mvc

The only endpoint you cant access is /gcs as that requires access to your hosts applicaton default credentials though you can work around that using GCE Metadata Server Emulator.

If you prefer using rkt,

sudo rkt run --insecure-options=image docker://salrashid123/mvc

rkt list

UUID		APP	IMAGE NAME					STATE	CREATED		STARTED		NETWORKS
36a7ac5b	mvc	registry-1.docker.io/salrashid123/mvc:latest	running	4 seconds ago	4 seconds ago	default:ip4=172.16.28.19

curl http://172.16.28.19:8080

To build from the git repo

cd WebApplicaton1
docker build -t mvc .
docker run -t -p 8080:8080 mvc

As reference, the following files were modified to listen on :8080 and for healthchecks on /_ah/health:

• Startup.cs
• Program.cs
• Controllers/HomeController.cs
• Views/Health.cshtml
• Views/GCS.cshtml
• project.json
• Dockerfile
• global.json
• hosting.json

---

To run localy without Docker, install dotnet-dev-1.0.0-preview2-1-003177 as shown in the Dockerfile and off of the microsoft .net [install guides] (https://www.microsoft.com/net/core#ubuntu). Once installed, then,

cd src\WebApplication1\
dotnet restore
dotnet run

Using Google Cloud Libraries

You can even use Google Cloud APIs on docker now. Just reference Google.Cloud.Storage.V1 version of .net libraires.

After you reference it, you call GCP apis direclty under path /gcs. For example, see:

• project.json
• HomeController.cs
• Views/GCS.cshtml

in project.json, specify

"Google.Cloud.Storage.V1": "1.0.0-beta07"

The following list out some objects in the public USPTO GCS bucket. If you want to list the objects in your on project, please change uspto-pair while deploying the sample (you'll need to rebuild the docker image).

using Google.Cloud.Storage.V1;

var ret = "";
var client = StorageClient.Create();

foreach (var obj in client.ListObjects("uspto-pair", "").Take(100))
{
   ret = ret + "  " + obj.Name + "  ";
}

NOTE

If you want to build and run the docker container with GCP API code, you will need to provide the container some way to acquire an access_token for GCP. There are serveral ways to do that:

• Run the GCE Metadata Server Emulator.
• Pass in json certificate file to the container: Alternatives to Metadata tokens for containers

Pack/Publish steps

If you want to pack the deployment to a .dll using dotnet publish

in project.json, if the following artifiact from Visual Studio exists, remove

  "scripts": {
    "prepublish": [ "bower install", "dotnet bundle" ],
    "postpublish": [ "dotnet publish-iis --publish-folder %publish:OutputPath% --framework %publish:FullTargetFramework%" ]
  }

Then make the build/release .dll

cd WebApplication1/src/WebApplication1
dotnet restore
dotnet publish  -c Release

To run the local pack directly:

dotnet bin/Release/netcoreapp1.0/publish/WebApplication1.dll

Finally, edit the Dockerfile

FROM microsoft/dotnet:1.1.0-sdk-projectjson

ADD . /app
WORKDIR /app

EXPOSE 8080
WORKDIR /app/src/WebApplication1/
ENTRYPOINT ["dotnet", "bin/Release/netcoreapp1.0/publish/WebApplication1.dll"]

Note: As of 8/16, dotnet is currently not supported on Alpine Linux.

Deploying

Deploying to GCP requires your gcloud environment to get setup:

gcloud auth login
gcloud config set project <your_project>

AppEngine

Deploying to GAE is pretty simple:

gcloud app deploy app.yaml

Then, http://your_project.appspot.com

ContainerEngine

To deploy on GKE, you need to setup the replication controllers and frontend loadbalancer services as well as a small cluster.

Note

In the example below, the configuration ponts to a public image for the above two examples. You can configure your own private repository or use Google Container Registry.

The prebuilt image is on docker.io registry under:

• WebApplication1: docker.io/salrashid123/mvc

Replication Controllers

web-rc.yaml (edit the image section in the yaml below to use a different referenced image)

apiVersion: v1
kind: ReplicationController
metadata:
  name: web-rc
  labels:
    type: web-type
spec:
  replicas: 2
  template:
    metadata:
      labels:
        type: web-type
    spec:
      containers:
      - name: web-container
        image: salrashid123/mvc
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
          protocol: TCP

Services

web-svc.yaml

apiVersion: v1
kind: Service
metadata:
  name: web-srv
  labels:
    type: web-type
spec:
  type: LoadBalancer
  ports:
  - name: web
    port: 80
    protocol: TCP
    targetPort: 8080
  selector:
    type: web-type

Set the Runnng zone

gcloud config set compute/zone us-central1-a

Create a Firewall rule

gcloud compute firewall-rules create allow-http --allow tcp:80

NAME       NETWORK SRC_RANGES RULES  SRC_TAGS TARGET_TAGS
allow-http default 0.0.0.0/0  tcp:80

Note The above service maps port 80 --> 8080 in the container and sets the firewall rules apprpriately. If you want to directly use 8080 throughout, modify the services file and firewall rule.

Create a GKE Cluster

gcloud beta container clusters create cluster-1 --num-nodes 2

NAME       ZONE           MASTER_VERSION  MASTER_IP      MACHINE_TYPE   STATUS
cluster-1  us-central1-a  1.0.6           104.197.76.93  n1-standard-1  RUNNING

List instances in the Cluster

gcloud compute instances list

Create ReplicationController and Services

kubectl create -f web-rc.yaml
kubectl create -f web-srv.yaml

List nodes, pods, replication controllers and services

kubectl get no
NAME            LABELS           STATUS
gke-cluster-1-e997c6b4-node-38so   kubernetes.io/hostname=gke-cluster-1-e997c6b4-node-38so   Ready
gke-cluster-1-e997c6b4-node-knp6   kubernetes.io/hostname=gke-cluster-1-e997c6b4-node-knp6   Ready

kubectl get po
NAME           READY     STATUS    RESTARTS   AGE
web-rc-lfvky   1/1       Running   0          2m
web-rc-mcrg3   1/1       Running   0          2m

kubectl get rc
CONTROLLER   CONTAINER(S)    IMAGE(S)           SELECTOR        REPLICAS
web-rc       web-container   salrashid123/mvc   type=web-type   2

kubectl get svc
NAME         LABELS        SELECTOR        IP(S)                   PORT(S)
kubernetes   component=apiserver,provider=kubernetes 10.167.240.1  443/TCP
web-srv      type=web-type type=web-type   10.167.251.162          80/TCP
                                           104.197.194.190 <<<<<<<<<<<<<<<<<

Note: The service lists the public IP address of the LoadBalancer (it may take a couple of minutes to provision it).

Now that we have a public ip, the service is available

http://104.197.194.190

Container-Optimized OS

Container VMs simply spin up one container per GCE instance with docker already installed and the instructions to strartup the image thats specified.

The following insruction set setups a managed instance group, healthcheck and loadbalancer. You can use the managed instance group to later auto (or manually) scale the number of VMs up or down

For more information, see: Conatiner Optimized OS

The Container VM is defined by the following yaml file:

containers.yaml

#cloud-configs
users:
- name: cloudservice
  uid: 2000

write_files:
- path: /etc/systemd/system/cloudservice.service
  permissions: 0644
  owner: root
  content: |
    [Unit]
    Description=Start a simple docker container

    [Service]
    Environment="HOME=/home/cloudservice"
    ExecStartPre=/usr/share/google/dockercfg_update.sh
    ExecStart=/usr/bin/docker run -t -p 8080:8080 --name=dotnetservice docker.io/salrashid123/mvc:latest
    ExecStop=/usr/bin/docker stop dotnetservice
    ExecStopPost=/usr/bin/docker rm dotnetservice

runcmd:
- systemctl daemon-reload
- systemctl start cloudservice.service

Create the firewall rule, instance template, helthcheck and target pool

gcloud compute firewall-rules create allow-http --allow tcp:80

gcloud compute instance-templates create dotnet \
    --image-family container-vm \
    --image-project=google-containers \
    --tags dotnetserver \
    --metadata-from-file google-container-manifest=containers.yaml \
    --machine-type f1-micro

gcloud compute http-health-checks create httpcheck \
    --port 80 --request-path "/_ah/health" 

gcloud compute  target-pools create tphttp \
    --health-check httpcheck --region us-central1

Note

The above service maps port 80 --> 8080 in the container and sets the firewall rules apprpriately.
If you want to directly use 8080 throughout, modify containers.yaml file, the firewall rule and the healthcheck port.

Then setup the actual forwarding rule. Note he IP address

gcloud compute forwarding-rules create fwddotnet \
    --region us-central1 --ip-protocol TCP \
    --ports=80 --target-pool tphttp

NAME      REGION      IP_ADDRESS     IP_PROTOCOL TARGET
fwddotnet us-central1 104.197.85.206 TCP         us-central1/targetPools/tphttp

Note the IP address for the forwarding rule 104.197.85.206

The example above uses a GCP Network LoadBalancer. Since we are using HTTP only, the alternative could be to stup an HTTP LoadBalancer.

gcloud compute instance-groups managed create dotnetgroup \
    --zone us-central1-a --base-instance-name coreclr \
    --size 2 --template dotnet \
    --target-pool tphttp

NAME ZONE  BASE_INSTANCE_NAME SIZE TARGET_SIZE GROUP       INSTANCE_TEMPLATE AUTOSCALED
dotnetgroup us-central1-a coreclr                 2           dotnetgroup dotnet

You should see the instance group up, running and available for traffic:

Finally, the service should be available at the port for the forwarding rule:

http://104.197.85.206

Building Locally

The easiest way to extend these samples is to generate the docker images and test the images themselves.

Optionally, if you want to extend and deploy these images locally, you will need docker. Running the images directly inside docker mimics the deployment runtime on GCP (linux images) as opposed to directly running on windows or in Visual Studio.

However, if you want to run dotnet directly on your machine, make sure you atleast have (on linux):

dotnet --version
1.0.0-preview2-1-003177

dotnet restore
cd src/WebApplication1/
dotnet run -p project.json

on Windows