Test your Rust deployment

Table of contents

Prerequisites

Overview

In this section, you'll learn how to use Docker Desktop to deploy your application to a fully-featured Kubernetes environment on your development machine. This lets you to test and debug your workloads on Kubernetes locally before deploying.

Create a Kubernetes YAML file

In your docker-rust-postgres directory, create a file named docker-rust-kubernetes.yaml. Open the file in an IDE or text editor and add the following contents. Replace DOCKER_USERNAME/REPO_NAME with your Docker username and the name of the repository that you created in Configure CI/CD for your Rust application.

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    service: server
  name: server
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      service: server
  strategy: {}
  template:
    metadata:
      labels:
        service: server
    spec:
      initContainers:
        - name: wait-for-db
          image: busybox:1.28
          command: ['sh', '-c', 'until nc -zv db 5432; do echo "waiting for db"; sleep 2; done;']
      containers:
        - image: DOCKER_USERNAME/REPO_NAME
          name: server
          imagePullPolicy: Always
          ports:
            - containerPort: 8000
              hostPort: 5000
              protocol: TCP
          env:
            - name: ADDRESS
              value: 0.0.0.0:8000
            - name: PG_DBNAME
              value: example
            - name: PG_HOST
              value: db
            - name: PG_PASSWORD
              value: mysecretpassword
            - name: PG_USER
              value: postgres
            - name: RUST_LOG
              value: debug
          resources: {}
      restartPolicy: Always
status: {}
---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    service: db
  name: db
  namespace: default
spec:
  replicas: 1
  selector:
    matchLabels:
      service: db
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        service: db
    spec:
      containers:
        - env:
            - name: POSTGRES_DB
              value: example
            - name: POSTGRES_PASSWORD
              value: mysecretpassword
            - name: POSTGRES_USER
              value: postgres
          image: postgres
          name: db
          ports:
            - containerPort: 5432
              protocol: TCP
          resources: {}
      restartPolicy: Always
status: {}
---
apiVersion: v1
kind: Service
metadata:
  labels:
    service: server
  name: server
  namespace: default
spec:
  type: NodePort
  ports:
    - name: "5000"
      port: 5000
      targetPort: 8000
      nodePort: 30001
  selector:
    service: server
status:
  loadBalancer: {}
---
apiVersion: v1
kind: Service
metadata:
  labels:
    service: db
  name: db
  namespace: default
spec:
  ports:
    - name: "5432"
      port: 5432
      targetPort: 5432
  selector:
    service: db
status:
  loadBalancer: {}

In this Kubernetes YAML file, there are four objects, separated by the ---. In addition to a Service and Deployment for the database, the other two objects are:

  • A Deployment, describing a scalable group of identical pods. In this case, you'll get just one replica, or copy of your pod. That pod, which is described under template, has just one container in it. The container is created from the image built by GitHub Actions in Configure CI/CD for your Rust application.
  • A NodePort service, which will route traffic from port 30001 on your host to port 5000 inside the pods it routes to, allowing you to reach your app from the network.

To learn more about Kubernetes objects, see the Kubernetes documentation.

Deploy and check your application

  1. In a terminal, navigate to docker-rust-postgres and deploy your application to Kubernetes.

    $ kubectl apply -f docker-rust-kubernetes.yaml

    You should see output that looks like the following, indicating your Kubernetes objects were created successfully.

    deployment.apps/server created
deployment.apps/db created
service/server created
service/db created

  2. Make sure everything worked by listing your deployments.

    $ kubectl get deployments

    Your deployment should be listed as follows:

    NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
db       1/1     1            1           2m21s
server   1/1     1            1           2m21s

    This indicates all of the pods you asked for in your YAML are up and running. Do the same check for your services.

    $ kubectl get services

    You should get output like the following.

    NAME         TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
db           ClusterIP   10.105.167.81    <none>        5432/TCP         109s
kubernetes   ClusterIP   10.96.0.1        <none>        443/TCP          9d
server       NodePort    10.101.235.213   <none>        5000:30001/TCP   109s

    In addition to the default kubernetes service, you can see your service-entrypoint service, accepting traffic on port 30001/TCP.

  3. In a terminal, curl the service.

    $ curl http://localhost:30001/users
[{"id":1,"login":"root"}]

  4. Run the following command to tear down your application.

    $ kubectl delete -f docker-rust-kubernetes.yaml

Summary

In this section, you learned how to use Docker Desktop to deploy your application to a fully-featured Kubernetes environment on your development machine.

Related information: