How to build my own container images in CloudBees CI (CloudBees Core) on Modern Cloud Platforms

pipeline {
  parameters {
    string defaultValue: '2.401.2.6', name: 'AGENT_VERSION', trim: true
    string defaultValue: '', name: 'REGISTRY', trim: true
  }
  agent none
  stages {
    stage('build-image'){
      agent {
        kubernetes {
          yaml '''
kind: Pod
spec:
  containers:
  - name: kaniko
    image: gcr.io/kaniko-project/executor:debug
    command:
    - sleep
    args:
    - infinity
    volumeMounts:
    - name: cache
      mountPath: /cache
  volumes:
  - name: cache
    persistentVolumeClaim:
      claimName: kaniko-cache
'''
        }
      }
      stages {
        stage('Dockerfile'){
          steps {
            sh '''cat >Dockerfile <<EOF
FROM cloudbees/cloudbees-core-agent:${AGENT_VERSION}
USER root
RUN dnf update -y && dnf install -y maven-3.5.4 && dnf clean all && rm -rf /var/cache/dnf
RUN alternatives --remove-all java
RUN alternatives --install /usr/bin/java java /usr/lib/jvm/jre-11-openjdk/bin/java 99
USER jenkins
EOF
'''
          }
        }
        stage('Build with Kaniko') {
          steps {
            container('kaniko') {
              sh '''#!/busybox/sh
                 /kaniko/executor \
                   --context `pwd` \
                   --cache=true \
                   --cache-dir=/cache \
                   --cache-run-layers \
                   --cache-repo=${REGISTRY} \
                   --destination=${REGISTRY}:${AGENT_VERSION}
                 '''
            }
          }
        }
      }
    }
    stage('parallel scans'){
      parallel {
        stage('syft'){
          agent {
            kubernetes {
              yaml '''
kind: Pod
spec:
  containers:
  - name: syft
    image: YOUR_SYFT_IMAGE
    command:
    - sleep
    args:
    - infinity
    env:
    - name: DOCKER_CONFIG
      value: /config
    volumeMounts:
    - mountPath: /config
      name: registry-config
      readOnly: true
  volumes:
  - name: registry-config
    secret:
      secretName: registry-config
'''
            }
          }
          steps {
            container('syft') {
              sh 'syft ${REGISTRY}:${AGENT_VERSION} -o json=sbom.json'
              archiveArtifacts artifacts: 'sbom.json', followSymlinks: false
            }
          }
        }
        stage('grype'){
          agent {
            kubernetes {
              yaml '''
kind: Pod
spec:
  containers:
  - name: grype
    image: YOUR_GRYPE_IMAGE
    command:
    - sleep
    args:
    - infinity
    env:
    - name: DOCKER_CONFIG
      value: /config
    volumeMounts:
    - mountPath: /config
      name: registry-config
      readOnly: true
  volumes:
  - name: registry-config
    secret:
      secretName: registry-config
'''
            }
          }
          steps {
            container('grype') {
              sh 'grype ${REGISTRY}:${AGENT_VERSION} --file vulnerabilities.json --output json'
              archiveArtifacts artifacts: 'vulnerabilities.json', followSymlinks: false
            }
          }
        }
      }
    }
  }
}

FROM alpine:3.18

WORKDIR /app

RUN apk add --no-cache \
    curl

RUN curl -sSfL https://raw.githubusercontent.com/anchore/syft/main/install.sh | sh -s -- -b /usr/local/bin

CMD ["syft", "-h"]

FROM alpine:3.18

WORKDIR /app

RUN apk add --no-cache \
    curl

RUN curl -sSfL https://raw.githubusercontent.com/anchore/grype/main/install.sh | sh -s -- -b /usr/local/bin

CMD ["grype", "-h"]