Why docker is not found? I want to deploy a Next.js app to AWS ECS.

λ  (Server)  server-side renders at runtime (uses getInitialProps or getServerSideProps)
○  (Static)  automatically rendered as static HTML (uses no initial props)
●  (SSG)     automatically generated as static HTML + JSON (uses getStaticProps)
$ echo "Building the Docker image..."
Building the Docker image...
$ docker build -t $IMAGE_TAG .
/bin/sh: eval: line 163: docker: not found

Cleaning up project directory and file based variables
00:00
ERROR: Job failed: exit code 127

gitlab-ci.yml

image: docker:20.10.7 # Use a specific Docker image

services:
  - docker:20.10.7-dind # Docker-in-Docker service

stages:
  - build
  - test
  - deploy

variables:
  DOCKER_IMAGE: 'tikex-repository'
  AWS_DEFAULT_REGION: eu-central-1
  AWS_ECR_REGISTRY: 767397666295.dkr.ecr.eu-central-1.amazonaws.com
  AWS_ECR_REPOSITORY: tikex-repository
  ECS_CLUSTER: tikex-cluster
  ECS_SERVICE: tikex-service
  ECS_TASK_DEFINITION: my-task-def

before_script:
  - docker --version
  - docker info
  - aws configure set aws_access_key_id $AWS_ACCESS_KEY_ID
  - aws configure set aws_secret_access_key $AWS_SECRET_ACCESS_KEY
  - aws configure set default.region $AWS_DEFAULT_REGION

build:
  stage: build
  image: docker:latest
  services:
    - docker:dind
  script:
    - docker version # Verify Docker is installed and running
    - docker info
    - docker build -t $DOCKER_IMAGE:$CI_COMMIT_SHA .
    - docker tag $DOCKER_IMAGE:$CI_COMMIT_SHA $AWS_ECR_REGISTRY/$AWS_ECR_REPOSITORY:$CI_COMMIT_SHA
    - docker push $AWS_ECR_REGISTRY/$AWS_ECR_REPOSITORY:$CI_COMMIT_SHA

test:
  stage: test
  image: node:latest
  services:
    - docker:dind
  script:
    - npm install
    - npm run test

deploy:
  stage: deploy
  image: amazon/aws-cli
  script:
    - aws ecs update-service --cluster $ECS_CLUSTER --service $ECS_SERVICE --task-definition $ECS_TASK_DEFINITION --force-new-deployment

Dockerfile:

# Use an official Node.js runtime as a parent image
FROM node:18-alpine

# Set the working directory in the container
WORKDIR /app

# Copy package.json and package-lock.json
COPY package*.json ./

# Install dependencies
RUN npm install

# Copy the rest of the application code
COPY . .

# Build the Next.js application
ARG NEXT_PUBLIC_BASE_URL=""
RUN npm run build

# Expose the port the app runs on
EXPOSE 3000

# Start the Next.js application
CMD ["npm", "start"]