Gitlab CI/CD pipeline passed, but no changes were applied to the server - kubernetes

Question

I am testing automation by applying Gitlab CI/CD to a GKE cluster. The app is successfully deployed, but the source code changes are not applied (eg renaming the html title).
I have confirmed that the code has been changed in the gitlab repository master branch. No other branch.
CI/CD simply goes through the process below.
push code to master branch
builds the NextJS code
builds the docker image and pushes it to GCR
pulls the docker image and deploys it in.
The content of the menifest file is as follows.
.gitlab-ci.yml
stages:
- build-push
- deploy
image: docker:19.03.12
variables:
GCP_PROJECT_ID: PROJECT_ID..
GKE_CLUSTER_NAME: cicd-micro-cluster
GKE_CLUSTER_ZONE: asia-northeast1-b
DOCKER_HOST: tcp://docker:2375/
DOCKER_TLS_CERTDIR: ""
REGISTRY_HOSTNAME: gcr.io/${GCP_PROJECT_ID}
DOCKER_IMAGE_NAME: ${CI_PROJECT_NAME}
DOCKER_IMAGE_TAG: latest
services:
- docker:19.03.12-dind
build-push:
stage: build-push
before_script:
- docker info
- echo "$GKE_ACCESS_KEY" > key.json
- docker login -u _json_key --password-stdin https://gcr.io < key.json
script:
- docker build --tag $REGISTRY_HOSTNAME/$DOCKER_IMAGE_NAME:$DOCKER_IMAGE_TAG .
- docker push $REGISTRY_HOSTNAME/$DOCKER_IMAGE_NAME:$DOCKER_IMAGE_TAG
deploy:
stage: deploy
image: google/cloud-sdk
script:
- export USE_GKE_GCLOUD_AUTH_PLUGIN=True
- echo "$GKE_ACCESS_KEY" > key.json
- gcloud auth activate-service-account --key-file=key.json
- gcloud config set project $GCP_PROJECT_ID
- gcloud config set container/cluster $GKE_CLUSTER_NAME
- gcloud config set compute/zone $GKE_CLUSTER_ZONE
- gcloud container clusters get-credentials $GKE_CLUSTER_NAME --zone $GKE_CLUSTER_ZONE --project $GCP_PROJECT_ID
- kubectl apply -f deployment.yaml
- gcloud container images list-tags gcr.io/$GCP_PROJECT_ID/${CI_PROJECT_NAME} --filter='-tags:*' --format="get(digest)" --limit=10 > tags && while read p; do gcloud container images delete "gcr.io/$GCP_PROJECT_ID/${CI_PROJECT_NAME}#$p" --quiet; done < tags
Dockerfile
# Install dependencies only when needed
FROM node:16-alpine AS deps
# Check https://github.com/nodejs/docker-node/tree/b4117f9333da4138b03a546ec926ef50a31506c3#nodealpine to understand why libc6-compat might be needed.
RUN apk add --no-cache libc6-compat
WORKDIR /app
# Install dependencies based on the preferred package manager
COPY package.json yarn.lock* package-lock.json* pnpm-lock.yaml* ./
RUN \
if [ -f yarn.lock ]; then yarn --frozen-lockfile; \
elif [ -f package-lock.json ]; then npm ci; \
elif [ -f pnpm-lock.yaml ]; then yarn global add pnpm && pnpm i --frozen-lockfile; \
else echo "Lockfile not found." && exit 1; \
fi
# Rebuild the source code only when needed
FROM node:16-alpine AS builder
WORKDIR /app
COPY --from=deps /app/node_modules ./node_modules
COPY . .
# Next.js collects completely anonymous telemetry data about general usage.
# Learn more here: https://nextjs.org/telemetry
# Uncomment the following line in case you want to disable telemetry during the build.
# ENV NEXT_TELEMETRY_DISABLED 1
RUN yarn build
# If using npm comment out above and use below instead
# RUN npm run build
# Production image, copy all the files and run next
FROM node:16-alpine AS runner
WORKDIR /app
ENV NODE_ENV production
# Uncomment the following line in case you want to disable telemetry during runtime.
# ENV NEXT_TELEMETRY_DISABLED 1
RUN addgroup --system --gid 1001 nodejs
RUN adduser --system --uid 1001 nextjs
COPY --from=builder /app/public ./public
# Automatically leverage output traces to reduce image size
# https://nextjs.org/docs/advanced-features/output-file-tracing
COPY --from=builder --chown=nextjs:nodejs /app/.next/standalone ./
COPY --from=builder --chown=nextjs:nodejs /app/.next/static ./.next/static
USER nextjs
EXPOSE 3000
ENV PORT 3000
CMD ["node", "server.js"]
deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: frontweb-lesson-prod
labels:
app: frontweb-lesson
spec:
selector:
matchLabels:
app: frontweb-lesson
template:
metadata:
labels:
app: frontweb-lesson
spec:
containers:
- name: frontweb-lesson-prod-app
image: gcr.io/PROJECT_ID../REPOSITORY_NAME..:latest
ports:
- containerPort: 3000
resources:
requests:
cpu: 200m
---
apiVersion: v1
kind: Service
metadata:
name: frontweb-lesson-prod-svc
labels:
app: frontweb-lesson
spec:
selector:
app: frontweb-lesson
ports:
- name: http
port: 80
protocol: TCP
targetPort: 3000
type: LoadBalancer
loadBalancerIP: "EXTERNAL_IP.."
Is there something I'm missing?

Answer 1

By default,imagepullpolicy will be Always but there could be chances if there is no change in the deployment file when applying it might not update the deployment. As you are using the same label each time latest.
As there different between kubectl apply and kubectl patch command
What you can do is add minor label change or annotation change in deployment and check image will get updated with kubectl apply command too otherwise it will be mostly unchange response of kubectl apply
Ref : imagepullpolicy
You should avoid using the :latest tag when deploying containers in
production as it is harder to track which version of the image is
running and more difficult to roll back properly.