error when trying to run ui (app) on kubernetes?

Question

Basically when i try to run my app(UI) on kubernetess using kubectl the pod fails and says error.

logs of the pod

> wootz@0.1.0 start /usr/src/app
> node scripts/start.js

internal/modules/cjs/loader.js:626
    throw err;
    ^

Error: Cannot find module 'react-dev-utils/chalk'
Require stack:
- /usr/src/app/scripts/start.js
    at Function.Module._resolveFilename (internal/modules/cjs/loader.js:623:15)
    at Function.Module._load (internal/modules/cjs/loader.js:527:27)
    at Module.require (internal/modules/cjs/loader.js:681:19)
    at require (internal/modules/cjs/helpers.js:16:16)
    at Object.<anonymous> (/usr/src/app/scripts/start.js:19:15)
    at Module._compile (internal/modules/cjs/loader.js:774:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:785:10)
    at Module.load (internal/modules/cjs/loader.js:641:32)
    at Function.Module._load (internal/modules/cjs/loader.js:556:12)
    at Function.Module.runMain (internal/modules/cjs/loader.js:837:10) {
  code: 'MODULE_NOT_FOUND',
  requireStack: [ '/usr/src/app/scripts/start.js' ]
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! wootz@0.1.0 start: `node scripts/start.js`
npm ERR! Exit status 1
npm ERR!
npm ERR! Failed at the wootz@0.1.0 start script.
npm ERR! This is probably not a problem with npm. There is likely additional log                                                                                                                                                             ging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /root/.npm/_logs/2019-06-17T15_56_02_649Z-debug.log

uipersistantvolume

kind: PersistentVolume
apiVersion: v1
metadata:
  name: ui-initdb-pv-volume
  labels:
    type: local
    app: ui
spec:
  storageClassName: manual
  capacity:
    storage: 1Mi
  accessModes:
    - ReadOnlyMany
  hostPath:
    path: "/home/vignesh/pagedesigneryamls/client"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: ui-initdb-pv-claim-one
  labels:
    app: ui
spec:
  storageClassName: manual
  accessModes:
    - ReadOnlyMany
  resources:
    requests:
      storage: 1Mi

uipersistantvolumetwo

kind: PersistentVolume
apiVersion: v1
metadata:
  name: ui-initdb-pv-volume-two
  labels:
    type: local
    app: ui
spec:
  storageClassName: manual
  capacity:
    storage: 1Mi
  accessModes:
    - ReadOnlyMany
  hostPath:
    path: "/home/vignesh/pagedesigneryamls/client"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: ui-initdb-pv-claim-two
  labels:
    app: ui
spec:
  storageClassName: manual
  accessModes:
    - ReadOnlyMany
  resources:
    requests:
      storage: 1Mi

ui.yaml

apiVersion: v1
kind: Service
metadata:
  name: ui
  labels:
    app: ui
spec:

  ports:
  - name: myport
    port: 80
    targetPort: 3000

  selector:
    app: ui
    tier: frontend

---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: ui
  labels:
    app: ui
spec:
  selector:
    matchLabels:
      app: ui
      tier: frontend
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: ui
        tier: frontend
    spec:

      containers:
      - image: suji165475/devops-sample:updatedclientdockerfile
        name: ui
        ports:
        - containerPort: 80
          name: myport
        volumeMounts:
        - name: ui-persistent-storage-one
          mountPath: /usr/src/app
        - name: ui-persistent-storage-two
          mountPath: /usr/src/app/node_modules
      volumes:
      - name: ui-persistent-storage-one
        persistentVolumeClaim:
          claimName: ui-initdb-pv-claim-one
      - name: ui-persistent-storage-two
        persistentVolumeClaim:
          claimName: ui-initdb-pv-claim-two

the image used in the ui yaml was built using the following dockerfile

FROM node:12.4.0-alpine
RUN mkdir -p usr/src/app
WORKDIR /usr/src/app
COPY package.json package.json
RUN npm install && npm cache clean --force
RUN npm install -g webpack-cli
WORKDIR /usr/src/app
COPY . .
WORKDIR /usr/src/app
EXPOSE 3000
RUN npm run build
CMD [ "npm","start" ]

how can i solve the error Cannot find module 'react-dev-utils/chalk'?? Is there anything missing from the dockerfile??

Answer 1

Delete all of the volumes, persistent volumes, and persistent volume claims. Your code is in your image (you COPY . . to get it in) and you should run it from there.

Kubernetes is extremely ill-suited to be a live development environment. Notice here that you’re spending more YAML space on trying to inject your local source code into the container than everything else in your deployment combined; in a real production setup you’d also have to make sure your source code gets on to every single node (and assumes you even have access to the nodes; in many cloud-hosted environments you won’t).

I’d recommend developing your application normally — no Docker, no Kubernetes — and only once it works, worry about packaging it up and deploying it. Things like rolling zero-downtime restarts in Kubernetes are rather different from live code reloads in a development environment.