GitLab CI/CD - The Platform That Does Everything (Usually)

GitLab tries to be everything to everyone. Sometimes this works great - you get source control, CI/CD, security scanning, and project management in one place. Sometimes you spend your weekend debugging why the exact same pipeline that worked Friday is failing Monday.

What They Don't Tell You in the Sales Demo

YAML Hell is Real: Your `.gitlab-ci.yml` file will become a 200-line monster that nobody fully understands. Indentation matters. Spaces vs tabs will destroy your soul. And the error messages? "Job failed with exit code 1" tells you exactly nothing.

CI Minutes Burn Fast: Those free 400 minutes? Gone in a week if you're doing Docker builds. Windows builds eat minutes like they're going out of style. macOS builds cost extra and take forever. I learned this the hard way when we added the webpack-bundle-analyzer plugin and suddenly our builds went from 5 minutes to 25 minutes. Took me three hours of debugging to realize it was analyzing every single chunk in parallel, spawning 47 worker processes that each hit GitLab's memory limits.

Shared Runners Are Slow: GitLab's shared runners work, but they're not fast. Your 30-second local build becomes a 5-minute CI build. Want faster builds? Bring your own runners and become a sysadmin.

Things That Will Bite You

• Cache invalidation: GitLab's cache is great until it randomly stops working and you can't figure out why. Cache keys containing forward slashes break silently on Windows runners. Fun fact: this breaks if your branch names have slashes like feature/user-auth.
• Environment variables: Work perfectly in your local Docker container, fail mysteriously in GitLab CI. The $CI_COMMIT_SHA variable gets truncated to 8 characters in some contexts but stays full-length in others.
• Windows runners: Slower than molasses and eat your CI minutes for breakfast. A 2-minute Linux npm install becomes a 12-minute Windows nightmare because Windows Defender scans every node_modules file.
• Security scanning: Finds 200 vulnerabilities, 180 are false positives you'll spend hours triaging. SAST flags every SQL query as injection risk, even parameterized ones.
• GitLab.com outages: More frequent than you'd expect for a platform charging enterprise prices. Database problems take down the whole platform for hours.

The All-in-One Promise (And Its Problems)

GitLab wants to be your entire DevOps toolchain. They've got source control, CI/CD, security scanning, project management, a container registry, and even monitoring.

This is great when it works. One login, one UI, everything talks to everything else. But when one piece breaks, it can take down your entire workflow. I've seen teams unable to deploy because GitLab's merge request approvals were having a bad day.

Real Talk on GitLab 18.1

GitLab 18.1 dropped in June 2025 with some actually useful stuff:

• Maven virtual registry (beta): Finally, centralized dependency management that doesn't suck. Still beta though, so YMMV.
• Duo Code Review: AI code reviews that are helpful about 60% of the time. Better than nothing.
• Variable precedence controls: Security teams can finally stop developers from overriding critical pipeline settings.

The GitLab Runner 18.1 bug fixes are real and they fixed some annoying edge cases. Still doesn't make Windows runners fast though.

Who Actually Uses This

Over 50% of Fortune 100 companies trust GitLab, including Deutsche Telekom, Goldman Sachs, and Nvidia. These companies have dedicated DevOps teams and enterprise budgets.

For smaller teams, the learning curve is steep. GitHub Actions is simpler if you just need CI/CD. Jenkins gives you more control if you don't mind the plugin hell.

But if you want everything in one place and have the patience for YAML debugging sessions, GitLab can work. Just don't expect it to be painless.

So you want to try GitLab CI/CD? Cool. Here's what you're actually signing up for, not the marketing fluff.

Pricing Reality Check

GitLab's pricing looks reasonable until you actually start using it:

Free Tier: 400 minutes/month sounds generous until your first Docker build eats 50 minutes. That's 8 builds if you're lucky. Add Windows testing? You're fucked.

Premium ($29/user/month): 10,000 minutes sounds like a lot. Our 15-person team burns through this in two weeks with a React app, Node API, and mobile builds. The AI features are neat but not game-changing.

Ultimate (contact sales): If you have to ask, you can't afford it. But seriously, 50,000 minutes plus all the enterprise security stuff. Worth it if compliance matters to your company.

Hidden Costs:

• Additional minutes: $10 per 1,000 minutes. Adds up fast.
• Windows runners: 2x minute multiplier. macOS: Even worse.
• Storage: $5 per 10GB monthly for artifacts and packages.
• Pro tip: GitLab counts parallel: 3 as burning 3x minutes. That matrix build strategy will bankrupt you fast.
• Storage gotcha: Every failed artifact still counts against your quota. Failed builds pile up storage costs.
• Bandwidth costs: Package registry downloads from external networks cost extra after 10GB/month.

Setup: The Three Ways to Hate Yourself

Option 1: GitLab.com (Easy Mode)

1. Sign up at gitlab.com
2. Import your repos from GitHub, Bitbucket, wherever
3. Add a `.gitlab-ci.yml` file
4. Watch it fail spectacularly

Pro tip: Start with the CI/CD templates. They're actually decent.

Option 2: Self-Managed (Hard Mode)

Want to run your own GitLab? Hope you like being a sysadmin.

Docker Compose: Quick to set up, breaks in creative ways. Good for testing, terrible for production.

Omnibus Package: Official installation method. Works reliably but you're now responsible for backups, updates, and 3am pager alerts.

Kubernetes: Helm charts available. If you already have a K8s cluster and want to make it more complicated, this is for you.

Minimum Requirements: 4GB RAM for "small teams." In reality, you need 8GB minimum or GitLab will crawl. Scale up fast - GitLab is hungry.

Option 3: GitLab Dedicated (Rich Mode)

Single-tenant SaaS for enterprises with compliance requirements and deep pockets. GitLab manages the infrastructure, you pay enterprise money. Actually works well if you can afford it.

YAML Configuration: Welcome to Hell

Here's a simple pipeline that will break in 47 different ways:

stages:
  - build
  - test
  - deploy

build_app:
  stage: build
  script:
    - npm install
    - npm run build
  artifacts:
    paths:
      - dist/
    expire_in: 1 hour
  cache:
    key: ${CI_COMMIT_REF_SLUG}
    paths:
      - node_modules/

test_app:
  stage: test
  script:
    - npm test
  coverage: '/Coverage: \d+\.\d+%/'

deploy_prod:
  stage: deploy
  script:
    - rsync -avz dist/ user@server:/var/www/
  only:
    - main
  when: manual

What Will Go Wrong:

• Cache won't work because of some obscure cache policy - the "simple" pipeline example in their docs omits the 15 environment variables you actually need
• Artifacts will expire before deploy job runs (default 30 minutes, who thought that was enough?)
• The rsync will fail because of SSH key issues - GitLab's SSH agent forwarding is broken by default
• Coverage regex won't match your test output format - Jest changed their format in v28 and broke everyone's regex
• Variables will be undefined for mysterious reasons - mostly because variable expansion happens at weird times

Integrations That Actually Matter

AWS: Works well. OIDC integration is solid, no more long-lived access keys.

Kubernetes: GitLab's Auto DevOps is impressive when it works. Fails spectacularly when your app doesn't fit their assumptions.

Docker Registry: Built-in and actually good. Vulnerability scanning included.

Slack: Notifications work. Prepare for spam.

Jira: Integration exists. Your project manager will be happy.

Migration: Abandon Hope

From Jenkins: Migration guides exist but every Jenkins setup is a unique snowflake. Plan for months, not weeks.

From GitHub Actions: Easier migration since both use YAML, but GitLab's syntax is different enough to be annoying.

From Azure DevOps: Good luck. No official migration tools. Manual conversion of everything.

Reality Check: Budget 3-6 months for a real migration. Your pipelines will be broken and slow for weeks while you figure out GitLab's quirks. Have a rollback plan.

GitLab's enterprise features are where they make their money. Some are genuinely useful, others are marketing checkbox items for procurement departments.

AI Features: The Good, Bad, and Overhyped

GitLab Duo is their AI suite. It's... fine. Not revolutionary, but helpful enough to justify the cost if you're already paying for Ultimate.

Code Suggestions

Works about as well as GitHub Copilot. Sometimes suggests brilliant code, sometimes suggests complete garbage. The VS Code extension integration is decent.

AI Code Review

Duo Code Review finds real issues about 60% of the time. The other 40% it suggests "improvements" that make code worse. Like when it suggested replacing Promise.all() with sequential awaits "for better readability" - completely missing the performance implications. Use @GitLabDuo in merge request comments - it's actually pretty helpful for complex logic.

Vulnerability Auto-fixes

This is where the AI shines. Automatically fixes SAST vulnerabilities like SQL injection (CWE-89) and command injection (CWE-78). Saves hours of manual remediation work.

Pricing Reality

• Premium/Ultimate: Basic AI included
• Duo Pro: $19/user/month for enhanced features
• Duo Enterprise: Contact sales (translation: expensive as fuck)

Security Scanning: Actually Good (When It Works)

GitLab's security scanning is legitimately one of their best features. Built-in SAST, DAST, container scanning, and dependency scanning.

Static Application Security Testing (SAST)

GitLab 18.1 added PHP support for Advanced SAST. Cross-file analysis works well. Finds real vulnerabilities.

Dynamic Application Security Testing (DAST)

Tests your running app for vulnerabilities. Detection parity with secret detection is a nice touch.

Container Scanning

Scans your Docker images for known CVEs. Integrates with the built-in container registry. Actually useful.

The Problems

• False positives everywhere: Expect 200 "critical" issues, 180 of which are bullshit. SAST flags every SQL query as injection risk, even parameterized ones. Container scanner freaks out over base image CVEs you can't fix. Dependency scanner flags every dev dependency as "critical production risk."
• Slow scans: Security jobs double your pipeline time. DAST scans take 20+ minutes for a simple app.
• Report fatigue: Your developers will ignore security reports after the first week. Too many false positives kill real issue visibility.

Supply Chain Security

SLSA Level 1 compliance and SBOM generation for compliance teams who love acronyms.

Compliance: For Teams That Love Paperwork

GitLab Ultimate includes compliance features for heavily regulated industries:

Custom Compliance Frameworks

Define custom controls and validation rules. Mostly for showing auditors that you have "controls in place."

Pipeline Execution Policies

Variable precedence controls let security teams override pipeline variables. Actually useful for enforcing security scanning.

Audit Logs

Comprehensive audit trails for everything. Required for SOX, HIPAA, and other compliance frameworks that make developers miserable.

Performance: It's Complicated

Shared Runners

Slow but included. Linux runners are okay, Windows runners are painfully slow, macOS runners are expensive and slow.

Self-Hosted Runners

Install your own for better performance. Now you're managing infrastructure. Pick your poison.

Auto-scaling

Docker Machine auto-scaling works but is complex to set up. Kubernetes executor is better if you have K8s expertise.

Caching

GitLab's caching is good when it works. Cache keys are finicky. Expect to spend hours debugging cache invalidation issues.

Pipeline Optimization Tips

• Parallel jobs reduce total time but burn more minutes
• Docker layer caching helps Docker builds
• Dependency caching saves time on repeated builds

Package Registries: Actually Useful

Built-in package registries for Docker, npm, Maven, PyPI, and more.

Maven Virtual Registry (Beta)

Maven Virtual Registry (Beta): Aggregates Maven Central and private repos behind one URL. Actually clever. Still beta though.

Docker Registry

Vulnerability scanning included. Image signing with Harbor integration.

Performance

Package downloads are fast. Storage costs add up though - $5 per 10GB monthly.

Monitoring: Because DevOps

Value Stream Analytics, DORA metrics, and pipeline analytics for teams that like charts.

Actually Useful

Lead time and deployment frequency metrics help identify bottlenecks.

Mostly Useless

Most of the dashboards are vanity metrics that don't change behavior.

Integration

Works with Prometheus, Grafana, and other monitoring tools you probably already have.