> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Reference Tags Reuse Configuration Integration Testing > This article explains how to use GitLab CI/CD reference tags and YAML anchors to share configuration snippets across multiple jobs. In this lesson, we’ll walk through how to leverage GitLab CI/CD reference tags (`!reference`) and standard YAML anchors to share configuration snippets across multiple jobs. By doing so, you can DRY up your pipeline definitions—pulling in values like `image`, `before_script`, or `script` from one job into another and avoiding duplication. *** ## 1. Basic YAML Anchors and `!reference` Tags GitLab CI/CD supports two primary mechanisms for reusing snippets: | Method | Syntax | Use Case | | ------------------- | --------------------------- | ------------------------------------------ | | YAML Anchors | `&anchor` / `*alias` | Share simple lists or maps within the file | | GitLab `!reference` | `!reference [job, section]` | Import complete sections (`script`, etc.) | ```yaml theme={null} # .gitlab-ci.yml .default_scripts: &default_scripts - ./default-script1.sh - ./default-script2.sh job1: script: - *default_scripts ``` Or use GitLab’s custom reference tag: ```yaml theme={null} # setup.yml .setup: script: - echo "creating environment" # .gitlab-ci.yml include: - local: setup.yml .teardown: after_script: - echo "deleting environment" test: script: - !reference [.setup, script] ``` YAML anchors work within the same file, while `!reference` can pull from hidden jobs or included files. *** ## 2. Preparing the Kubernetes Environment Let’s define two hidden jobs: one for Node.js and one for Kubernetes deployment. We’ll attach an anchor (`&kubernetes_deploy_job`) to reuse the Kubernetes job’s `image` later. ```yaml theme={null} variables: # Add global variables here… .prepare_nodejs_environment: image: node:14 script: - npm install .prepare_deployment_environment: &kubernetes_deploy_job image: name: alpine:3.7 dependencies: [] before_script: - wget https://storage.googleapis.com/kubernetes-release/release/$(wget -q -O - https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl - chmod +x ./kubectl - mv ./kubectl /usr/bin/kubectl - apk add --no-cache gettext - envsubst --version ``` Make sure hidden jobs (prefixed with `.`) are not executed on their own—they only serve as references. *** ## 3. Two Almost-Identical Integration Tests Consider two integration testing jobs—dev and staging. They share the same `image`, identical `before_script`, and `script` blocks: ```yaml theme={null} k8s_dev_deploy: stage: dev-deploy image: alpine:3.7 needs: - k8s_stage_deploy before_script: - apk --no-cache add curl jq script: - echo "$INGRESS_URL" - curl -s -k "https://$INGRESS_URL/live" | jq -r .status | grep -i live - curl -s -k "https://$INGRESS_URL/ready" | jq -r .status | grep -i ready k8s_stage_deploy: stage: stage-deploy image: alpine:3.7 needs: - k8s_dev_deploy before_script: - apk --no-cache add curl jq script: - echo "$INGRESS_URL" - curl -s -k "https://$INGRESS_URL/live" | jq -r .status | grep -i live - curl -s -k "https://$INGRESS_URL/ready" | jq -r .status | grep -i ready ``` Rather than duplicating, let’s pull these blocks into new jobs via `!reference`. *** ## 4. Reusing the `image` Definition We can reuse the `image` from `.prepare_deployment_environment` with: ```yaml theme={null} k8s_dev_integration_testing: stage: dev-deploy image: !reference [.prepare_deployment_environment, image] needs: - k8s_dev_deploy before_script: - apk --no-cache add curl jq script: - echo "$INGRESS_URL" - curl -s -k "https://$INGRESS_URL/live" | jq -r .status | grep -i live - curl -s -k "https://$INGRESS_URL/ready" | jq -r .status | grep -i ready k8s_stage_integration_testing: stage: stage-deploy image: !reference [.prepare_deployment_environment, image] needs: - k8s_stage_deploy before_script: - apk --no-cache add curl jq script: - echo "$INGRESS_URL" - curl -s -k "https://$INGRESS_URL/live" | jq -r .status | grep -i live - curl -s -k "https://$INGRESS_URL/ready" | jq -r .status | grep -i ready ``` Now, updating the base image in one place updates both jobs. *** ## 5. Reusing `before_script` and `script` Blocks To avoid repeating `before_script` or `script`, reference the dev-integration job directly: ```yaml theme={null} k8s_dev_integration_testing: stage: dev-deploy image: !reference [.prepare_deployment_environment, image] needs: - k8s_dev_deploy before_script: - apk --no-cache add curl jq script: - echo "$INGRESS_URL" - curl -s -k "https://$INGRESS_URL/live" | jq -r .status | grep -i live - curl -s -k "https://$INGRESS_URL/ready" | jq -r .status | grep -i ready k8s_stage_integration_testing: stage: stage-deploy image: !reference [.prepare_deployment_environment, image] needs: - k8s_stage_deploy before_script: !reference [k8s_dev_integration_testing, before_script] script: !reference [k8s_dev_integration_testing, script] ``` This ensures both jobs stay in sync for setup and testing steps. *** ## 6. Full Snippet with Artifacts and Environment For a consolidated pipeline, include artifacts and environment details alongside your reused blocks: ```yaml theme={null} artifacts: reports: dotenv: - app_ingress_url.env environment: name: staging url: "https://$INGRESS_URL" k8s_stage_integration_testing: stage: stage-deploy image: !reference [.prepare_deployment_environment, image] needs: - k8s_stage_deploy before_script: !reference [k8s_dev_integration_testing, before_script] script: !reference [k8s_dev_integration_testing, script] ``` *** ## Conclusion By combining standard YAML anchors (`&` / `*`) with GitLab’s custom `!reference` tags, you can effectively DRY up your CI/CD definitions. Pull in common `image`, `before_script`, or `script` sections from hidden or existing jobs—simplifying maintenance and reducing errors. *** ## Links and References * [GitLab CI/CD Reference Tags](https://docs.gitlab.com/ee/ci/yaml/#reference) * [GitLab CI/CD Anchors and Aliases](https://docs.gitlab.com/ee/ci/yaml/#anchors) * [Kubernetes Official Documentation](https://kubernetes.io/docs/) * [jq JSON Processor](https://stedolan.github.io/jq/)