using service account

.gitlab-ci.yml

stages:
  - deploy
deploy_app:
  image: bitnami/kubectl:latest
  stage: deploy
  environment: production
  script:
    - USER_TOKEN=$(cat /var/run/secrets/kubernetes.io/serviceaccount/token)
    - CERTIFICATE_AUTHORITY_DATA=$(cat /var/run/secrets/kubernetes.io/serviceaccount/ca.crt | base64 -i -w0 -)
    - kubectl config set-cluster k8s --server="https://kubernetes.default.svc"
    - kubectl config set clusters.k8s.certificate-authority-data ${CERTIFICATE_AUTHORITY_DATA}
    - kubectl config set-credentials gitlab --token="${USER_TOKEN}"
    - kubectl config set-context default --cluster=k8s --user=gitlab
    - kubectl config use-context default
    - kubectl set image deployment my-app web=${CI_REGISTRY}/user/repo/${CI_PROJECT_PATH_SLUG}:${CI_COMMIT_SHORT_SHA} --kubeconfig ./config --namespace default