fastify-kubernetes

Fastify Kubernetes client plugin.

This plugin uses the official Node.js Kubernetes client under the hood.

The installed version of @kubernetes/client-node is the v1.x.x. The targeted Kubernetes version is from the v1.28 to v1.30.

For more info about supported Kubernetes version see here.

Generally speaking newer clients will work with older Kubernetes, but compatability isn't 100% guaranteed.

npm install --save fastify-kubernetes

Add it to your project with register and you are done!

const fastify = require('fastify')()

fastify.register(require('fastify-kubernetes'), {
  // Optional, defaults to OS default Kubeconfig file location
  file: '/home/app/.kube/config',
  // Context to use
  context: 'production'
})

fastify.get('/pods', async function (req, reply) {
  const client = this.kubernetes.api.CoreV1Api
  const result = await client.listNamespacedPod(this.kubernetes.namespace)
  reply.send(result.body.items)
})

fastify.listen(3000, err => {
  if (err) throw err
})

This module is now pure ESM. This is to use the same module system of the @kubernetes/client-node (as from v1.0.0).

This shouldn't be a problem with Node.js v22.13.0 or newer.

If you are seeing an error like this one:

Error [ERR_REQUIRE_ESM]: require() of ES Module node_modules/fastify-kubernetes/fastify-kubernetes.js from my_script.js not supported.
Instead change the require of fastify-kubernetes.js in my_script.js to a dynamic import() which is available in all CommonJS modules.
    at Object.<anonymous> (my_script.js:2:20) {
  code: 'ERR_REQUIRE_ESM'
}

You have multimple options to solve the problem:

• Upgrade you Node.js version to >=22.13.0
• Use await import('fastify-kubernetes') instead of require('fastify-kubernetes')
• Convert your project to use ESM instead of CommonJS

All properties are optional.

• kubeconfig: Kubernetes config file loading mode. Default is "auto".
  • KubeConfig: Load custom KubeConfig instance (see @kubernetes/client-node docs).
  • "auto": Choose the first available mode in this order: Choose the first available config mode in this order: "file", "yaml", "in-cluster", and "default".
  • "file": Load config file from file option.
  • "yaml": Load config from yaml option.
  • "in-cluster": Load in-cluster kubeconfig file.
  • "default": Load config file the default OS location.
• file: kubeconfig (YAML format) file path.
• yaml: Raw kubeconfig yaml data (string of Node.js Buffer).
• context: Loads Context by name.
• cluster: Loads Context by Curster's name.
• user: Loads Context by User's name.
• namespace: Loads Context by Namespace.
• name: Nested (Fastify) decorator name (will inject fastify.kubernetes[key]).

import Fastify from 'fastify'

const fastify = Fastify()

fastify
  .register(require('fastify-kubernetes'), {
    context: 'eu-cluster-0',
    name: 'eu'
  })
  .register(require('fastify-kubernetes'), {
    context: 'us-cluster-0',
    name: 'us'
  })

fastify.get('/', async function (req, reply) {
  const euClient = this.kubernetes.eu.api.CoreV1Api
  const usClient = this.kubernetes.us.api.CoreV1Api
  // ------------
  // do your stuff here
  // ------------
  reply.send(yourResult)
})

// TODO: start server, etc..

The plugin will inject six properties under kubernetes decorator.

• config is the KubeConfig instance.
• context is the current Context's name.
• cluster is the Cluster's name.
• user is the User's name.
• namespace is the Namespace, defaults to "default".
• api is an object containing all known client instances (see below).

You can retrieve a client by its original name from the kubernetes lib.

import kubernetes from 'fastify-kubernetes'

const fastify = Fastify()

fastify.register(kubernetes)

// Load plugins (http server not running)
await fastify.ready()

const client0 = fastify.kubernetes.api.CoreV1Api
const client1 = fastify.kubernetes.api.BatchV1Api
const client2 = fastify.kubernetes.api.BatchV1beta1Api

You can also manually creates Api clients.

import { BatchV1Api } from '@kubernetes/client-node'
import kubernetes from 'fastify-kubernetes'

const fastify = Fastify()

fastify.register(kubernetes)

// Load plugins (http server not running)
await fastify.ready()

const batchApi = fastify.kubernetes.config.makeApiClient(BatchV1Api)

const cronJobs = await batchApi.listNamespacedCronJob({ namespace: fastify.kubernetes.namespace })