Skillintermediate

Common GitLab CI/CD Issues and Solutions

**Problem:** YAML formatting errors prevent pipeline execution.

Claude Code Knowledge Pack7/10/2026

Overview

Common GitLab CI/CD Issues and Solutions

Syntax Errors

Invalid YAML Syntax

Problem: YAML formatting errors prevent pipeline execution.

Common causes:

Inconsistent indentation (mixing tabs and spaces)
Missing colons after keys
Incorrect list formatting
Unquoted special characters

Examples:

# ❌ Wrong indentation
job_name:
script:
  - echo "test"

# ✅ Correct indentation
job_name:
  script:
    - echo "test"

# ❌ Missing colon
job_name
  script:
    - echo "test"

# ✅ Correct syntax
job_name:
  script:
    - echo "test"

# ❌ Unquoted special characters
job_name:
  script:
    - echo $VAR: value

# ✅ Quoted special characters
job_name:
  script:
    - echo "$VAR: value"

Solution: Use a YAML linter or GitLab's CI Lint tool to validate syntax.

Reserved Keyword as Job Name

Problem: Using reserved keywords as job names causes validation errors.

Reserved keywords:

image, services, stages, types
before_script, after_script, variables
cache, include, pages, default, workflow

# ❌ Using reserved keyword
image:
  stage: build
  script:
    - echo "build"

# ✅ Use a different name
build_image:
  stage: build
  script:
    - echo "build"

Job Configuration Issues

Missing `script` Keyword

Problem: Every job must have a script section (except some special jobs like trigger).

# ❌ Missing script
test_job:
  stage: test

# ✅ With script
test_job:
  stage: test
  script:
    - npm test

Undefined Stage Reference

Problem: Job references a stage that doesn't exist in stages definition.

# ❌ Undefined stage
stages:
  - build
  - test

deploy_job:
  stage: deploy  # 'deploy' stage not defined
  script:
    - ./deploy.sh

# ✅ Stage defined
stages:
  - build
  - test
  - deploy

deploy_job:
  stage: deploy
  script:
    - ./deploy.sh

Invalid Job Dependencies

Problem: Referencing non-existent jobs in dependencies or needs.

# ❌ References non-existent job
test_job:
  stage: test
  dependencies:
    - build_job  # This job doesn't exist
  script:
    - npm test

# ✅ Valid dependency
build_job:
  stage: build
  script:
    - npm run build
  artifacts:
    paths:
      - dist/

test_job:
  stage: test
  dependencies:
    - build_job
  script:
    - npm test

Circular Dependencies with `needs`

Problem: Creating circular dependencies with needs keyword.

# ❌ Circular dependency
job_a:
  needs: [job_b]
  script: echo "A"

job_b:
  needs: [job_a]
  script: echo "B"

# ✅ Valid DAG
job_a:
  script: echo "A"

job_b:
  needs: [job_a]
  script: echo "B"

Variable Issues

Undefined Variable Reference

Problem: Referencing variables that don't exist.

# ❌ Undefined variable
deploy_job:
  script:
    - echo "Deploying to $UNDEFINED_ENV"

# ✅ Define variable
variables:
  DEPLOY_ENV: "staging"

deploy_job:
  script:
    - echo "Deploying to $DEPLOY_ENV"

Variable Scope Issues

Problem: Variables not available in expected scope.

# ❌ Job variable not available globally
job_a:
  variables:
    MY_VAR: "value"
  script:
    - echo $MY_VAR

job_b:
  script:
    - echo $MY_VAR  # Not available here

# ✅ Use global variable
variables:
  MY_VAR: "value"

job_a:
  script:
    - echo $MY_VAR

job_b:
  script:
    - echo $MY_VAR

Hardcoded Secrets

Problem: Sensitive data exposed in pipeline configuration.

# ❌ Hardcoded credentials
deploy_job:
  script:
    - export API_KEY="sk_live_1234567890"
    - ./deploy.sh

# ✅ Use CI/CD variables or secrets
deploy_job:
  script:
    - ./deploy.sh  # API_KEY from CI/CD variables
  secrets:
    API_KEY:
      vault: production/api/key@ops

Artifact and Cache Issues

Artifacts Not Passed Between Jobs

Problem: Jobs can't access files from previous jobs.

# ❌ No artifacts defined
build_job:
  stage: build
  script:
    - npm run build

test_job:
  stage: test
  script:
    - ls dist/  # Directory doesn't exist

# ✅ With artifacts
build_job:
  stage: build
  script:
    - npm run build
  artifacts:
    paths:
      - dist/
    expire_in: 1 hour

test_job:
  stage: test
  needs: [build_job]
  script:
    - ls dist/  # Now available

Cache Not Working

Problem: Dependencies downloaded on every job run.

Common causes:

Wrong cache paths
Incorrect cache key
Cache policy misconfiguration
Runner doesn't support caching

# ❌ Wrong cache configuration
test_job:
  cache:
    paths:
      - node_modules/  # Wrong path or not created
  script:
    - npm ci
    - npm test

# ✅ Correct cache configuration
variables:
  npm_config_cache: "$CI_PROJECT_DIR/.npm"

test_job:
  cache:
    key: ${CI_COMMIT_REF_SLUG}
    paths:
      - .npm/
      - node_modules/
  script:
    - npm ci --cache .npm --prefer-offline
    - npm test

Cache vs Artifacts Confusion

Problem: Using cache for job outputs instead of artifacts.

# ❌ Using cache for build outputs
build_job:
  cache:
    paths:
      - dist/  # Should be artifacts
  script:
    - npm run build

# ✅ Correct usage
build_job:
  cache:
    paths:
      - node_modules/  # Dependencies (cache)
  artifacts:
    paths:
      - dist/  # Build outputs (artifacts)
  script:
    - npm ci
    - npm run build

Rules and Conditions Issues

Conflicting Rules

Problem: Multiple rules that contradict each other.

# ❌ Conflicting rules
deploy_job:
  script:
    - ./deploy.sh
  rules:
    - if: '$CI_COMMIT_BRANCH == "main"'
      when: always
    - if: '$CI_COMMIT_BRANCH == "main"'
      when: never  # Conflicts with above

# ✅ Clear rules
deploy_job:
  script:
    - ./deploy.sh
  rules:
    - if: '$CI_COMMIT_BRANCH == "main" && $CI_PIPELINE_SOURCE != "schedule"'
      when: on_success
    - when: never

Mixing `rules` with `only`/`except`

Problem: Cannot use rules with only/except in the same job.

# ❌ Mixing rules and only/except
deploy_job:
  script:
    - ./deploy.sh
  only:
    - main
  rules:
    - if: '$CI_COMMIT_TAG'

# ✅ Use rules only
deploy_job:
  script:
    - ./deploy.sh
  rules:
    - if: '$CI_COMMIT_BRANCH == "main"'
    - if: '$CI_COMMIT_TAG'

Incorrect `changes` Usage

Problem: changes not working as expected.

# ❌ Changes with wrong pipeline source
test_job:
  script:
    - npm test
  rules:
    - changes:
        - src/**/*.js
  # Won't work on branch pipelines without if condition

# ✅ Correct changes usage
test_job:
  script:
    - npm test
  rules:
    - if: '$CI_PIPELINE_SOURCE == "merge_request_event"'
      changes:
        - src/**/*.js
    - if: '$CI_COMMIT_BRANCH == $CI_DEFAULT_BRANCH'

Docker and Service Issues

Image Pull Failures

Problem: Cannot pull Docker images.

Common causes:

Image doesn't exist
Authentication required
Network issues
Using :latest without recent pull

# ❌ Non-existent or inaccessible image
test_job:
  image: mycompany/nonexistent:latest
  script:
    - npm test

# ✅ Valid, accessible image
test_job:
  image: node:18-alpine
  script:
    - npm test

# ✅ Private registry with authentication
test_job:
  image: registry.gitlab.com/mygroup/myimage:v1.0
  before_script:
    - echo $CI_REGISTRY_PASSWORD | docker login -u $CI_REGISTRY_USER --password-stdin $CI_REGISTRY
  script:
    - npm test

Service Connection Issues

Problem: Cannot connect to services (databases, etc.).

# ❌ Wrong service alias or missing variables
test_job:
  image: node:18
  services:
    - postgres:14
  script:
    - npm run test:integration  # Connection fails

# ✅ Proper service configuration
test_job:
  image: node:18
  services:
    - name: postgres:14
      alias: postgres
  variables:
    POSTGRES_DB: testdb
    POSTGRES_USER: test
    POSTGRES_PASSWORD: test
    DATABASE_URL: "postgres://test:test@postgres:5432/testdb"
  script:
    - npm run test:integration

Using `:latest` Tag

Problem: Unpredictable behavior with :latest tags.

# ❌ Using latest tag
build_job:
  image: node:latest  # Could change unexpectedly
  script:
    - npm run build

# ✅ Pin specific version
build_job:
  image: node:18.17.0-alpine
  script:
    - npm run build

# ✅ Even better: Use SHA digest
build_job:
  image: node@sha256:a6385a6bb2fdcb7c48fc871e35e32af8daaa82c518f934fcd0e5a42c0dd6ed71
  script:
    - npm run build

Performance Issues

Slow Pipeline Execution

Problem: Pipelines take too long to complete.

Solutions:

Use caching:

.node_cache:
  cache:
    key: ${CI_COMMIT_REF_SLUG}
    paths:
      - node_modules/
      - .npm/

build_job:
  extends: .node_cache
  script:
    - npm ci --cache .npm
    - npm run build

Use needs for parallel execution:

# Instead of sequential stages
build_a:
  stage: build
  script: make build_a

build_b:
  stage: build  # Runs in parallel with build_a
  script: make build_b

test_a:
  stage: test
  needs: [build_a]  # Starts immediately after build_a
  script: make test_a

Use parallel jobs:

test_job:
  script:
    - npm test -- --shard=$CI_NODE_INDEX/$CI_NODE_TOTAL
  parallel: 5

Cache Miss Rate High

Problem: Cache frequently invalidated or not used.

# ❌ Cache key changes too often
test_job:
  cache:
    key: $CI_COMMIT_SHA  # Different for every commit
    paths:
      - node_modules/

# ✅ Stable cache key
test_job:
  cache:
    key: ${CI_COMMIT_REF_SLUG}-${CI_PROJECT_DIR}/package-lock.json
    paths:
      - node_modules/

Downloading Same Artifacts Multiple Times

Problem: Multiple jobs downloading same artifacts unnecessarily.

# ❌ All artifacts downloaded
build_a:
  artifacts:
    paths:
      - dist_a/

build_b:
  artifacts:
    paths:
      - dist_b/

test_job:
  needs: [build_a, build_b]
  script:
    - test dist_a/  # Only needs dist_a

# ✅ Use dependencies to control downloads
test_job:
  needs:
    - build_a
    - build_b
  dependencies:
    - build_a  # Only download from build_a
  script:
    - test dist_a/

Security Issues

Secrets in Logs

Problem: Sensitive data visible in job logs.

# ❌ Secrets printed to logs
deploy_job:
  script:
    - echo "API Key: $API_KEY"  # Visible in logs
    - ./deploy.sh

# ✅ Mask variables and avoid printing
deploy_job:
  script:
    - ./deploy.sh
  # Mark API_KEY as masked in CI/CD settings

Unpinned Dependencies

Problem: Vulnerable or malicious dependencies could be installed.

# ❌ Unpinned dependencies
install_job:
  script:
    - npm install  # Could install different versions

# ✅ Locked dependencies
install_job:
  script:
    - npm ci  # Uses package-lock.json

# ✅ With hash verification (Python)
install_job:
  script:
    - pip install -r requirements.txt --require-hashes

Insecure Script Patterns

Problem: Scripts vulnerable to injection or other attacks.

# ❌ Command injection risk
deploy_job:
  script:
    - curl $EXTERNAL_URL | bash  # Dangerous

# ✅ Verify and validate
deploy_job:
  script:
    - curl -o script.sh $EXTERNAL_URL
    - sha256sum -c script.sh.sha256
    - bash script.sh

Environment and Deployment Issues

Environment Not Created

Problem: Deployment environments not showing in GitLab UI.

# ❌ Missing environment keyword
deploy_job:
  script:
    - ./deploy.sh staging

# ✅ With environment
deploy_job:
  script:
    - ./deploy.sh staging
  environment:
    name: staging
    url: https://staging.example.com

Manual Jobs Not Stopping Pipeline

Problem: Pipeline continues without waiting for manual job.

# ❌ Pipeline continues
deploy_staging:
  script:
    - ./deploy.sh
  when: manual

deploy_production:
  needs: [deploy_staging]  # Starts immediately
  script:
    - ./deploy.sh

# ✅ Use allow_failure: false
deploy_staging:
  script:
    - ./deploy.sh
  when: manual
  allow_failure: false  # Pipeline waits

deploy_production:
  needs: [deploy_staging]
  script:
    - ./deploy.sh

Review App Cleanup Issues

Problem: Review apps not automatically stopped.

# ❌ No cleanup
deploy_review:
  script:
    - ./deploy_review.sh
  environment:
    name: review/$CI_COMMIT_REF_SLUG
    url: https://$CI_ENVIRONMENT_SLUG.example.com

# ✅ With auto-stop and stop job
deploy_review:
  script:
    - ./deploy_review.sh
  environment:
    name: review/$CI_COMMIT_REF_SLUG
    url: https://$CI_ENVIRONMENT_SLUG.example.com
    on_stop: stop_review
    auto_stop_in: 3 days

stop_review:
  script:
    - ./stop_review.sh
  environment:
    name: review/$CI_COMMIT_REF_SLUG
    action: stop
  when: manual

Runner Issues

No Runners Available

Problem: Jobs stuck in "pending" state.

Solutions:

Check runner tags match job tags
Verify runners are online and not paused
Check runner capacity and queue
Review runner permissions for project

# If job requires specific tags
build_job:
  tags:
    - docker
    - linux
  script:
    - make build

# Ensure runners with these tags are available and active

Runner Timeout

Problem: Jobs fail due to timeout.

# ❌ Default timeout too short
long_running_job:
  script:
    - ./long_process.sh  # Takes > 1 hour

# ✅ Increase timeout
long_running_job:
  script:
    - ./long_process.sh
  timeout: 3h

Include and Template Issues

Include File Not Found

Problem: Cannot find included file.

# ❌ Wrong path
include:
  - local: 'templates/ci.yml'  # Missing leading slash

# ✅ Correct path
include:
  - local: '/templates/ci.yml'  # Absolute path from repo root

Circular Includes

Problem: Files include each other creating a loop.

# File A includes File B
# File B includes File A
# Results in: "Maximum includes depth reached"

# Solution: Restructure includes to avoid circular references

Include with Wrong Project Path

Problem: Cannot access files from other projects.

# ❌ Wrong project path or no access
include:
  - project: 'wrong-group/wrong-project'
    file: '/templates/ci.yml'

# ✅ Correct project path with access
include:
  - project: 'my-group/templates'
    ref: 'v1.2.3'
    file: '/templates/ci.yml'

Debugging Tips

Enable Debug Logging

Add debug variables to get more information:

variables:
  CI_DEBUG_TRACE: "true"  # Enable debug mode
  CI_DEBUG_SERVICES: "true"  # Debug service connections

Use `echo` for Debugging

Print variable values and script execution:

debug_job:
  script:
    - echo "Branch: $CI_COMMIT_BRANCH"
    - echo "Ref: $CI_COMMIT_REF_NAME"
    - env | sort  # Print all environment variables
    - set -x  # Enable command tracing
    - ./my_script.sh

Test Locally

Use tools to test pipelines locally:

# Using gitlab-ci-local
npm install -g gitlab-ci-local
gitlab-ci-local

# Using gitlab-ci

Common GitLab CI/CD Issues and Solutions

Overview

Common GitLab CI/CD Issues and Solutions

Syntax Errors

Invalid YAML Syntax

Reserved Keyword as Job Name

Job Configuration Issues

Missing script Keyword

Undefined Stage Reference

Invalid Job Dependencies

Circular Dependencies with needs

Variable Issues

Undefined Variable Reference

Variable Scope Issues

Hardcoded Secrets

Artifact and Cache Issues

Artifacts Not Passed Between Jobs

Cache Not Working

Cache vs Artifacts Confusion

Rules and Conditions Issues

Conflicting Rules

Mixing rules with only/except

Incorrect changes Usage

Docker and Service Issues

Image Pull Failures

Service Connection Issues

Using :latest Tag

Performance Issues

Slow Pipeline Execution

Cache Miss Rate High

Downloading Same Artifacts Multiple Times

Security Issues

Secrets in Logs

Unpinned Dependencies

Insecure Script Patterns

Environment and Deployment Issues

Environment Not Created

Manual Jobs Not Stopping Pipeline

Review App Cleanup Issues

Runner Issues

No Runners Available

Runner Timeout

Include and Template Issues

Include File Not Found

Circular Includes

Include with Wrong Project Path

Debugging Tips

Enable Debug Logging

Use echo for Debugging

Test Locally

Missing `script` Keyword

Circular Dependencies with `needs`

Mixing `rules` with `only`/`except`

Incorrect `changes` Usage

Using `:latest` Tag

Use `echo` for Debugging