Kubernetes: Deploy a Node Express Application

Before You Begin

To successfully perform this tutorial, you must have the following:

For Container Registry, Kubernetes and Load Balancers:
- A paid Oracle Cloud Infrastructure account.
- See Signing Up for Oracle Cloud Infrastructure.
For building applications and Docker images:
- One of the following local environments:
  - A MacOS or Linux machine.
  - A Windows machine with Linux support. For example:
    - Windows Subsystem for Linux
    - Oracle Virtual Box
- The following applications on your local environment:
  - JDK 11 and set JAVA_HOME in .bashrc.
  - Python 3.6.8+ and pip installer for Python 3
  - Kubernetes Client 1.11.9+
  - Apache Maven 3.0+
  - Docker 19.0.3+
  - Git 1.8+
  - Node.js 10+

Note

If you don't want to set up the required applications on your local environment, you can use Oracle Cloud Infrastructure Cloud Shell instead. The advantage of using Cloud Shell is all the required tools to manage your application are already installed and ready to use. Follow the steps one and two in:

Kubernetes Using Cloud Shell: Deploy a Spring Boot Application

Get the Applications for Linux on OCI Free Tier

If you want to use an OCI Free Tier Linux compute instance to manage your deployment, the following sections provide information to get the required software installed.

Install a Linux Instance

Install Node.js

Install Node.js on your system.

Run Install Commands

To install Node.js and NPM, run the following commands:

Oracle Linux:

sudo yum update

Set up the Yum repo for Node.js. Then install the nodejs package.

sudo yum install -y oracle-nodejs-release-el7
sudo yum install -y nodejs

Ubuntu:

sudo apt update

Install the nodejs and the npm packages.

sudo apt install -y nodejs
sudo apt install -y npm

Verify the installation.
```
node -v
npm -v
```

Configure Firewall (Optional)

If you want to do browser-based testing of your Node application, make port 3000 available on your Linux instance.

Oracle Linux

sudo firewall-cmd --add-service=http --permanent
sudo firewall-cmd --add-service=https --permanent
sudo firewall-cmd --reload

Ubuntu Linux

sudo iptables -I INPUT 6 -m state --state NEW -p tcp --dport 3000 -j ACCEPT
sudo netfilter-persistent save

Create an Ingress Rule for your VCN (Optional)

Install Python 3 and Pip 3

Verify your current installation.
```
python3 --version
```

For Python 3, run the following commands:

Oracle Linux:

sudo yum update

sudo yum install -y python3

Ubuntu:

sudo apt update

sudo apt install -y python3

Verify the pip installation for Python3.
```
pip3 -V
```
Example output if pip for Python3 is installed:
```
pip <version> from xxx/lib/python3.x/site-packages/pip (python 3.x)
```

To install pip for Python 3, run the following commands:

Oracle Linux:

sudo yum update

sudo yum install -y python3-pip

Ubuntu:

sudo apt update

sudo apt install -y python3-pip

Verify the pip for Python 3 installation.
```
pip3 -V
```

Install Kubernetes Client

Verify your current installation:
```
kubectl version --client
```
If you have Kubernetes, then the version is <major-version>.<minor-version>. For example, for version 1.20, you get the following:
```
version.Info{Major:"1", Minor:"20"...
```
To install he kubectl client, refer to the following links:
- Install Kubernetes client on Linux
- Install Kubernetes client on MacOS
Verify the installation.
```
kubectl version --client
```

Install Docker

Verify your current installation:
```
docker -v
```
Oracle Linux
To install Docker on Oracle Linux, run the following commands.
```
sudo yum install docker-engine
```
```
sudo systemctl start docker
```
```
sudo systemctl enable docker
```
Note: The last command enables Docker to start on reboots.
Ubuntu Linux
To install Docker on Ubuntu Linux, refer to the following link: Get Docker
Verify the installation.
```
docker -v
```

1. Prepare

Prepare your environment to create and deploy your application.

Check your Service Limits

Log in to the Oracle Cloud Infrastructure Console.
Open the navigation menu, and click Governance and Administration. Under Governance, click Limits, Quotas and Usage.
Find your service limit for Regions:
- Filter for the following options:
  - Service: Regions
  - Scope: Tenancy
  - Resource: Subscribed region count
  - Compartment: <tenancy-name> (root)
- Find service limit:
  - Limit Name: subscribed-region-count
  - Service Limit: minimum 2
Find your available Compute core count for the VM.Standard.E3.Flex shape:
- Filter for the following options:
  - Service: Compute
  - Scope: <first-availability-domain>. Example: EMlr:US-ASHBURN-AD-1
  - Resource: Cores for Standard.E3.Flex and BM.Standard.E3.128 Instances
  - Compartment: <tenancy-name> (root)
- Find available core count:
  - Limit Name: standard-e3-core-ad-count
  - Available: minimum 1
- Repeat for Scope: <second-availability-domain> and <third-availability-domain>. Each region must have at least one core available for this shape.
Find out if you have 50 GB of Block Volume available:
- Filter for the following options:
  - Service: Block Volume
  - Scope: <first-availability-domain>. Example: EMlr:US-ASHBURN-AD-1
  - Resource Volume Size (GB)
  - Compartment: <tenancy-name> (root)
- Find available block volume storage:
  - Limit Name: total-storage-gb
  - Available: minimum 50
- Repeat for Scope: <second-availability-domain> and <third-availability-domain>. Each region must have at least 50 GB of block volume available.
Find out how many Flexible Load Balancers you have available:
- Filter for the following options:
  - Service: LbaaS
  - Scope: <your-region>. Example: us-ashburn-1
  - Resource: <blank>
  - Compartment: <tenancy-name> (root)
- Find the number of available flexible load balancers:
  - Limit Name: lb-flexible-count
  - Available: minimum 1

Note

This tutorial creates three compute instances with a VM.Standard.E3.Flex shape for the cluster nodes. To use another shape, filter for its core count. For example, for VM.Standard2.4, filter for Cores for Standard2 based VM and BM Instances and get the count.

For a list of all shapes, see VM Standard Shapes.

Note

This tutorial uses a 'Quick Create' workflow to create a cluster with a public regional subnet that hosts a flexible load balancer. To use a different load balancer, you can use a custom workflow to explicitly specify which existing network resources to use, including the existing subnets in which to create the load balancers.

To use another bandwidth for the load balancer, filter for its count, for example 100-Mbps bandwidth or 400-Mbps bandwidth.

Create an Authorization Token

Gather Required Information

Set up OCI Command Line Interface

Install a Python Virtual Environment and Wrapper

The Python virtualenv creates a folder that contains all the executables and libraries for your project.

The virtualenvwrapper is an extension to virtualenv. It provides a set of commands, which makes working with virtual environments much more pleasant. It also places all your virtual environments in one place. The virtualenvwrapper provides tab-completion on environment names.

Install virtualenv.
```
pip3 install --user virtualenv
```
Install virtualenvwrapper.
```
pip3 install --user virtualenvwrapper
```
Find the location of the virtualenvwrapper.sh script.
```
grep -R virtualenvwrapper.sh
```
Example paths:
- Linux example: /home/ubuntu/.local/bin/virtualenvwrapper.sh
- MacOS example: /usr/local/bin/virtualenvwrapper.sh
Configure the virtual environment wrapper in .bashrc.
```
sudo vi .bashrc
```
Append the following text.
```
# set up Python env
export WORKON_HOME=~/envs
export VIRTUALENVWRAPPER_PYTHON=/usr/bin/python3
export VIRTUALENVWRAPPER_VIRTUALENV_ARGS=' -p /usr/bin/python3 '
source <path-to-virtualenvwrapper.sh>
```
Replace <path-to-virtualenvwrapper.sh> with its value.
Based on the location of Python3 binaries in your environment, update /usr/bin/python3 to its correct location.
Save the file.

Activate the commands in the current window.

source ~/.bashrc

Example output:

virtualenvwrapper.user_scripts creating /home/ubuntu/envs/premkproject
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/postmkproject
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/initialize
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/premkvirtualenv
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/postmkvirtualenv
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/prermvirtualenv
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/postrmvirtualenv
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/predeactivate
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/postdeactivate
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/preactivate
virtualenvwrapper.user_scripts creating /home/ubuntu/envs/postactivate

Install OCI CLI

Start a virtual environment.
```
workon cli-app
```
Confirm that the name of your virtual environment, cli-app appears in the left of your command prompt.
Example: (cli-app) ubuntu@<ubuntu-instance-name>:~$
Install OCI CLI.
```
pip3 install oci-cli
```
Test the installation:
```
oci --version
```
If everything is set up correctly, you get the version.
```
oci --help
```

Configure the OCI CLI

Enter the following command in your virtual environment:
```
oci setup config
```
Enter your answers from the Gather Required Information section:
- Location for your config [$HOME/.oci/config]: <take-default>
- User OCID: <user-ocid>
- Tenancy OCID: <tenancy-ocid>
- Region (e.g. us-ashburn-1): <region-identifier>
Enter the following information to set up your OpenSSL API encryption keys:
- Generate a new API Signing RSA key pair? [Y/n]: Y
- Directory for your keys [$HOME/.oci]: <take-default>
- Name for your key [oci_api_key] <take-default>
Deactivate the virtual environment:
```
deactivate
```
The (cli-app) prefix in your environment is not displayed anymore.

Note

Your private key is oci_api_key.pem and your public key is oci_api_key_public.pem.

Add the Public Key to Your User Account.

Activate the cli-app environment:
```
workon cli-app
```
Display the public key.
```
cat $HOME/.oci/oci_api_key_public.pem
```
Copy the public key.
Add the public key to your user account:
- Go to the Console.
- In the navigation bar, select the Profile menu and then select User settings or My profile, depending on the option that you see.
- Click API Keys.
- Click Add API Key.
- Click Paste Public Key.
- Paste value from previous step, including the lines with BEGIN PUBLIC KEY and END PUBLIC KEY.
- Click Add.

Note

Whenever you want to use the OCI CLI, activate it with: workon cli-app
When you change project names, workon deactivates your current working environment. This way, you can quickly switch between environments.

2. Set Up a Cluster

Install and configure management options for your Kubernetes cluster. Later, deploy your application to this cluster.

Add Compartment Policy

If your username is in the Administrators group, then skip this section. Otherwise, have your administrator add the following policy to your tenancy:

allow group <the-group-your-username-belongs> to manage compartments in tenancy

With this privilege, you can create a compartment for all the resources in your tutorial.

Steps to Add the Policy

In the navigation bar, select the Profile menu and then select User settings or My profile, depending on the option that you see.
In the left pane, click Groups.
In a notepad, copy the Group Name that your username belongs.
Open the navigation menu and click Identity & Security. Under Identity, click Policies.
Select your compartment from the Compartment drop-down.
Click Create Policy.
Fill in the following information:
- Name: manage-compartments
- Description: Allow the group <the-group-your-username-belongs> to list, create, update, delete and recover compartments in the tenancy.
- Compartment: <your-tenancy>(root)
For Policy Builder, click Show manual editor.

Paste in the following policy:

allow group <the-group-your-username-belongs> to manage compartments in tenancy

Click Create.

Reference: The compartments resource-type in Verbs + Resource-Type Combinations for IAM

Create a Compartment

Add Resource Policy

If your username is in the Administrators group, then skip this section. Otherwise, have your administrator add the following policy to your tenancy:

allow group <the-group-your-username-belongs> to manage all-resources in compartment <your-compartment-name>

With this privilege, you can manage all resources in your compartment, essentially giving you administrative rights in that compartment.

Steps to Add the Policy

Create a Cluster with 'Quick Create'

Set Up Local Access to Your Cluster

After you create a Kubernetes cluster, set up your local system to access the cluster.

Sign in to the Oracle Cloud Infrastructure Console.
Open the navigation menu and click Developer Services. Under Containers & Artifacts, click Kubernetes Clusters (OKE).
Click the link to <your-cluster>.

The information about your cluster is displayed.
Click Access Cluster.
Click Local Access.
Follow the steps provided in the dialog. They are reprinted here for your reference.

Note

If you are not in your virtual environment, enter: workon cli-app before you run kubectl commands.
Check your oci CLI version.
```
oci -v
```
Make your .kube directory if it doesn't exist.
```
mkdir -p $HOME/.kube
```
Create a kubeconfig file for your setup. Use the information from Access Your Cluster dialog.
```
oci ce cluster create-kubeconfig <use data from dialog>
```
Export the KUBECONFIG environment variable.
```
export KUBECONFIG=$HOME/.kube/config
```
Note

If you want to have the environment variable start in a new shell, then add export KUBECONFIG=$HOME/.kube/config to your ~/.bashrc file.
Test your cluster configuration with the following commands.
List clusters:
```
kubectl get service
```
Get deployment details:
```
kubectl describe deployment
```
Get pods:
```
kubectl get pods
```
Note

Since no application is deployed, the last two commands produce: "No resources found in default namespace."
Note

To look at a different cluster, specify a different config file on the command line. Example:
```
kubectl --kubeconfig=</path/to/config/file>
```

With your cluster access set up, you are now ready to prepare your application for deployment.

3. Build a Local Application

Build a local application and a Docker image for the application.

Create a Local Application

Create your Node.js application.

Start an OCI CLI session.
Create a directory for your application.
```
mkdir node-hello-app
cd node-hello-app
```

Create a package.json file.

Create the file:

vi package.json

In the file, input the following text, update the optional author and repository fields and then save the file:

{
    "name": "node-hello-app",
    "version": "1.0.0",
    "description": "Node Express Hello application",
    "author": "Example User <username@example.com>",
    "main": "app.js",
    "scripts": {
        "start": "node app.js"
    },
    "repository": {
        "type": "git",
        "url": "git://github.com/username/repository.git"
    },
    "dependencies": {
        "express": "^4.0.0"
    },
    "license": "UPL-1.0"
}

Install the NPM packages.
```
npm install
```

Create a "Hello, World!" application.

Create the file:

vi app.js

In the file, input the following text and save the file:

const express = require('express')
const app = express()
port = 3000

app.get('/', function (req, res) {
    res.send('<h1>Hello World from Node.js!</h1>')
})

app.listen(port, function() {
    console.log('Hello World app listening on port ' + port);
})

You have successfully set up your Node.js app.

Run the Local Application

Run your Node.js application.

Run your Node.js application.
```
node app.js
```
The Node Express server starts and displays:
```
Hello World app listening on port 3000
```
Test the application using curl or your browser.
- To test with curl, enter:
```
curl -X GET http://localhost:3000
```
- To test with your browser, connect a browser window to: http://<your-ip-address>:3000 (Optional).
The app returns
```
<h1>Hello World from Node.js!</h1>
```
Stop the running application.

Press Ctrl+C to stop your application in the terminal window you started with.

You have successfully created a Hello World application using Node.js and Express.

References:

For detailed information on this example, see Getting Started with Express.

Build a Docker Image

Next, create a Docker image for your Node.js Express application.

Ensure you are in the node-hello-app directory.

Build a Docker image.

docker build -t node-hello-app .

You get a success message.

[INFO] BUILD SUCCESS
Successfully tagged node-hello-app:latest

Run the Docker image:

docker run --rm -p 3000:3000 node-hello-app:latest

Test the application.

curl -X GET http://localhost:3000

The app returns

<h1>Hello World from Node.js!</h1>

Stop the running application.

Congratulations! You have successfully created a Node.js Express image.

4. Deploy Your Docker Image

Push your Node.js Express image to OCI Container Registry. Then use the image to deploy your application.

Create a Docker Repository

Open the navigation menu and click Developer Services. Under Containers & Artifacts, click Container Registry.
In the left navigation, select <your-compartment-name>.
Click Create Repository.
Create a private repository with your choice of repo name:
```
<repo-name> = <image-path-name>/<image-name>
```
Example: node-apps/node-hello-app
You are now ready to push your local image to Container Registry.
Note

Before you can push a Docker image into a registry repository, the repository must exist in your compartment. If the repository does not exist, the Docker push command does not work correctly.
Note

The slash in a repository name does not represent a hierarchical directory structure. The optional <image-path-name> helps to organize your repositories.

Push Your Local Image

With your local Docker image created, push the image to the Container Registry.

Follow these steps.

Open your OCI CLI session.
Log in to OCI Container Registry:
```
docker login <region-key>.ocir.io
```
You are prompted for your login name and password.
- Username: <tenancy-namespace>/<user-name>
- Password: <auth-token>
List your local Docker images:
```
docker images
```
The Docker images on your system are displayed. Identify the image you created in the last section: node-hello-app
Tag your local image with the URL for the registry plus the repo name, so you can push it to that repo.
```
docker tag <your-local-image> <repo-url>/<repo-name>
```
- Replace <repo-url> with:
```
<region-key>.ocir.io/<tenancy-namespace>/
```
- Replace <repo-name> with:
  <image-folder-name>/<image-name> from the Create a Docker Repository section.
- Here is an example after combining both:
```
docker tag node-hello-app iad.ocir.io/my-namespace/node-apps/node-hello-app
```
  In this example, the components are:
  - Repo URL: iad.ocir.io/my-namespace/
  - Repo name: node-apps/node-hello-app
Note

OCI Container Registry now supports creating a registry repo in any compartment rather than only in the root compartment (tenancy). To push the image to the repo you created, combine the registry URL with the exact repo name. OCI Container Registry matches the unique repo name and pushes your image.
Check your Docker images to see if the image is copied.
```
docker images
```
- The tagged image has the same image ID as your local image.
- The tagged image name is:
```
<region-key>.ocir.io/<tenancy-namespace>/<image-path-name>/<image-name>
```

Push the image to Container Registry.

docker push <copied-image-name>:latest

Example:

docker push iad.ocir.io/my-namespace/node-apps/node-hello-app:latest

Open the navigation menu and click Developer Services. Under Containers & Artifacts, click Container Registry.

Find your image in Container Registry after the push command is complete.

Deploy the Image

With your image in Container Registry, you can now deploy your image and app.

Create a registry secret for your application. This secret authenticates your image when you deploy it to your cluster.
To create your secret, fill in the information in this template .
```
kubectl create secret docker-registry ocirsecret --docker-server=<region-key>.ocir.io  --docker-username='<tenancy-namespace>/<user-name>' --docker-password='<auth-token>'  --docker-email='<email-address>'
```
After the command runs, you get a message similar to: secret/ocirsecret created.
Verify that the secret is created. Issue the following command:
```
kubectl get secret ocirsecret --output=yaml
```
The output includes information about your secret in the yaml format.

Determine the host URL to your registry image using the following template:

<region-code>.ocir.io/<tenancy-namespace>/<repo-name>/<image-name>:<tag>

Example:

iad.ocir.io/my-namespace/node-apps/node-hello-app:latest

On your system, create a file called node-app.yaml with the following text:

Replace the following place holders:

<your-image-url>
<your-secret-name>

apiVersion: apps/v1
kind: Deployment
metadata:
  name: node-app
spec:
  selector:
    matchLabels:
      app: app
  replicas: 3
  template:
    metadata:
      labels:
        app: app
    spec:
      containers:
      - name: app
        image: <your-image-url>
        imagePullPolicy: Always
        ports:
        - name: app
          containerPort: 3000
          protocol: TCP
      imagePullSecrets:
        - name: <your-secret-name>
---
apiVersion: v1
kind: Service
metadata:
  name: node-app-lb
  labels:
    app: app
  annotations:
    service.beta.kubernetes.io/oci-load-balancer-shape: "flexible"
    service.beta.kubernetes.io/oci-load-balancer-shape-flex-min: "10"
    service.beta.kubernetes.io/oci-load-balancer-shape-flex-max: "100"
spec:
  type: LoadBalancer
  ports:
  - port: 3000
  selector:
    app: app

Deploy your application with the following command.
```
kubectl create -f node-app.yaml
```
Output:
```
deployment.apps/node-app created
service/node-app-lb created
```
Note

In the node-app.yaml file, the code after the dashes adds a flexible load balancer.

Test Your App

After you deploy your app, it might take the load balancer a few seconds to load.

Check if the load balancer is live:
```
kubectl get service
```
Repeat the command until load balancer is assigned an IP address.
Note

While waiting for the load balancer to deploy, you can check the status of your cluster with these commands:
- Get each pods status: kubectl get pods
- Get app status: kubectl get deployment
Use the load balancer IP address to connect to your app in a browser:
```
http://<load-balancer-IP-address>:3000
```
The browser displays: <h1>Hello World from Node.js!</h1>
Undeploy your application from the cluster. (Optional) To remove your application run this command:
```
kubectl delete -f node-app.yaml
```
Output:
```
deployment.apps/node-app deleted
service "node-app-lb" deleted
```
Your application is now removed from your cluster.

What's Next

You have successfully created a Hello World application, deployed it to a Kubernetes cluster and made it accessible on the internet, using the Node Express framework.

Check out these sites to explore more information about development with Oracle products:

Oracle Cloud Infrastructure Documentation

Kubernetes: Deploy a Node Express Application

Before You Begin 🔗

1. Prepare 🔗

2. Set Up a Cluster 🔗

3. Build a Local Application 🔗

4. Deploy Your Docker Image 🔗

What's Next 🔗

Before You Begin

1. Prepare

2. Set Up a Cluster

3. Build a Local Application

4. Deploy Your Docker Image

What's Next