Nuxt.js (v2) with Node.js clusters.

cluster.js

// Create cluster.js in application folder,
// install "npm i nuxt-start",
// before start do "npm run build".
// Start this via "node ./cluster.js"

const cluster = require('cluster')
const os = require('os')

const { loadNuxt } = require('nuxt-start')

const port = 3000

const main = async () => {
  const nuxt = await loadNuxt({ for: 'start' })
  await nuxt.listen(port)
    .then(() => {
      // eslint-disable-next-line no-console
      console.log(`Worker ${cluster.worker.id} started`)
    })
}

if (cluster.isMaster) {
  const cpus = os.cpus().length
  for (let i = 0; i < cpus; i++) {
    cluster.fork()
  }

  cluster.on('exit', (worker, code) => {
    // eslint-disable-next-line no-console
    console.log(`Worker ${worker.id} finished with an error code: ${code}`)
    cluster.fork()
  })
} else {
  main()
}