Kubernetes is an open-source project for automating deployment, scaling, and management of containers. It has rapidly become the standard to run production workloads and the community around it is just great!
But developing on Kubernetes presents some challenges. The typical development workflow looks like this: write code, build a Docker image, push it to the registry, redeploy, validate your changes and repeat. This flow is not only slow, but it also prevents us from benefitting from standard features of the Node.js ecosystem such as application hot-reloaders or debuggers.
Okteto was created to solve this problem. On this blog post, I will show you how Okteto improves the developer experience in Kubernetes for Node.js developers. You will be able to take full advantage of tools like
nodemon, dependency caching or IDE debuggers while developing your application directly on Kubernetes.
Step 1: Deploy the Node.js Sample App
Get a local version of the Node.js Sample App by executing the following commands:
$ git clone https://github.com/okteto/node-getting-started
$ cd node-getting-started
k8s.yml file contains the Kubernetes manifests to deploy the Node.js Sample App. Run the application by executing:
You can deploy to your own Kubernetes cluster or give Okteto Cloud a try. Okteto Cloud is a development platform for Kubernetes applications. Sign up today to get a free developer account with 4CPUs and 8GB of RAM.
$ kubectl apply -f k8s.yml]deployment.apps “hello-world” created
service “hello-world” created
This is cool! You typed one command and a dev version of your application just runs 😎.
Step 2: Install the Okteto CLI
The Okteto CLI is an open-source project that lets you develop your applications directly on Kubernetes while taking advantage of well-known local tooling. We will use it to speed up our development cycle instead of using the typical development workflow based on building docker images and redeploying containers.
Install the Okteto CLI by running the following command:
$ curl https://get.okteto.com -sSfL | sh
$ wget https://downloads.okteto.com/cli/okteto-Windows-x86_64 -OutFile c:\windows\system32\okteto.exe
Step 3: Create your okteto manifest
To start developing on the Node.js Sample App you first need to create an okteto manifest.
With the Node.js Sample App deployed, run the following command to create your okteto manifest:
$ okteto initThis command walks you through creating an okteto manifest.
It only covers the most common items, and tries to guess sensible defaults.
See https://okteto.com/docs/reference/manifest for the official documentation about the okteto manifest.
Use the arrow keys to navigate: ↓ ↑ → ←
Select the deployment you want to develop:
Use default values
okteto init command will scan the available deployments in your Kubernetes namespace, and ask you to pick one.
hello-world deployment. It’s the one we deployed on the previous step.
✓ Deployment ‘hello-world’ successfully analyzed
✓ okteto manifest (okteto.yml) created
i Run ‘okteto up’ to activate your development container
okteto init command creates the following
This file defines how to activate a development container for the Node.js Sample App:
name: the name of the Kubernetes deployment you want to put on development mode.
command: the start command of the development container.
sync: the folders that will be synchronized between your local machine and the development container.
forward: a list of ports to forward from your development container.
okteto init command creates a
.stignore file to indicate which files shouldn’t be synchronized to your development container.
This is useful to avoid synchronizing binaries, build artifacts, git metadata or dependencies like
Step 4: Activate your development container
Next, execute the following command to activate your development container:
$ okteto up
✓ Persistent volume successfully attached
✓ Images successfully pulled ✓ Files synchronized Namespace: default
Forward: 3000 -> 3000
9229 -> 9229Welcome to your development container. Happy coding!
Working in your development container is the same as working on your local machine.
Start the application in hot-reload mode by running the following command:
default:hello-world app> nodemon index.jsyarn run v1.22.4
$ nodemon index.js
[nodemon] to restart at any time, enter `rs`
[nodemon] watching path(s): *.*
[nodemon] watching extensions: js,mjs,json
[nodemon] starting `node index.js`
Starting hello-world server…
Okteto automatically forwards port
3000 from your local computer to the development container, making it accessible via
localhost. Test your application by running the command below in a local shell:
$ curl localhost:3000Hello world!
Step 5: Develop directly in Kubernetes
index.js file in your favorite local IDE and modify the response message on line 5to be Hello world from the cluster!. Save your changes.
res.send(`Hello world from the cluster!`);
Okteto will synchronize your changes to your development container. Take a look at the development container shell and notice how the changes are detected by
nodemon and automatically hot reloaded.
[nodemon] restarting due to changes…
[nodemon] starting `node index.js`
Starting hello-world server...
Test your application by running the command below in a local shell:
$ curl localhost:3000Hello world from the cluster!
Cool! Your code changes were instantly applied to Kubernetes. No commit, build or push required 😎!
Step 6: Debug directly in Kubernetes
Okteto enables you to debug your applications directly from your favorite IDE. Let’s take a look at how that works in VS Code, one of the most popular IDEs for Node development.
Cancel the execution of
nodemon index.js from the development container shell by pressing
ctrl + c. Rerun your application in debug mode:
default:hello-world app> node — inspect-brk=0.0.0.0:9229 index.jsDebugger listening on ws://0.0.0.0:9229/73d8d793-b0c3–4310–86ee-3a42938a5df1
For help, see: https://nodejs.org/en/docs/inspector
Open the Debug extension and run the Connect to okteto debug configuration (or press the F5 shortcut):
“name”: “Connect to okteto”,
Add a breakpoint on
index.js, line 5. Call your application by running the command below from a local shell.
$ curl localhost:3000
The execution will halt at your breakpoint. You can then inspect the request, the available variables, etc…
Kubernetes has the potential to be a great development platform, providing replicable, resource-efficient and production-like development environments. We have shown you how to use Okteto to create a development workflow that also lets you take advantage of features like hot reloaders or debuggers while developing your application directly on Kubernetes.
Visit our website to know more about how to improve your team developer productivity with Okteto. Follow us on Twitter and join our #okteto channel in the Kubernetes community Slack to share your feedback with our community.