GitLab one of the popular DevOps platform out there, currently. I am evaluating a version GitLab 13.7-pre- release features. This post is supposed to be part of the bigger series with a unified structure. Evaluation in the context of existing infrastructure GitHub + Prometheus + Grafana.

GitLab main components: 

• Can be SaaS or self-managed
• Manages Internal Docker Registry
• Provide internal package registry ~ Nexus

Authentication and Authorisation with GitLab:

• Authentication with google
• GitLab roles and permissions model

GitLab continous integration and continous delivery capabilities:

• You need a runner (self hosted, or shared GitLab Runners ) where you can hit limits/costs 

Pipeline definition

• Pipeline described in yml file
  • Pipeline architecture
  • Pipeline settings
  • Pipeline nesting/Parent child 
• Pipeline stages
  • Deployments to Kubernetes
    • Runs Kubernetes agent in cluster
  • Alpha support for Serverless apps
  • Manual step (converting stage run to trigger manually)
    • Providing variables to manual stages
  • Deployment safety
    • Deploy freeze when deploy is not allowed
    • Environment protection 
      • Support only developer x maintainer roles
    • “Traffic Guards” – pipelines runs in parallel -> single deploy at a time ~> Ordering ???
    • Roll back deployment ~ history deployment
    • Rollout strategies
  • Terraform support
    • AFAIU – terraform state is hosted in gitlab storage
    • Development in progress
    • [Infrastructure as code](https://docs.gitlab.com/ee/user/infrastructure/)
  • Pipeline runners 
    • Shared
      • Job stage is run on n1-standard-1
      • Max n1-standard-2
      • CI pipeline minutes are the execution time for your pipelines on GitLab’s shared runners.
    • Custom Registered
      • Needed for bigger build machines
      • Requires installation/configuration/setup
      • Solving security concerns
      • And if I understand correctly you can run it at the end on your infrastructure => you pay for the machines
  • Pipeline versioning
    • Pipeline description in gitlab-ci.yml
  • Pipeline triggers

Pipeline additional features

• Notification
  • Slack (integration)
• Extension
  • Via docker image every job is `script`
• Monitoring
  • Pipeline monitoring via Expositng prometheus endpoint for your grafana
• Integration
  • For GitHub you Need Premium

GitLab Pricing model:

• Has the concept of minutes in the plan + buying extra ($10 per 1000min)
• Pay for the storage $60/10GB  see details
• strong push towards Premium with the cost $19/user/month.
• GitLab pricing

Conclusion

I haven’t studied GitLab offering super profoundly, but for building a new project, I would consider starting with it as it provides complete SDLC support (compared to Spinnaker it is CI + CD). Acts as SDLC management on top of the cloud provider – providing an easy way how to comply with the majority of measures from certification, e.g. SOC 2, but those are the gold plan features ($99/user/month). This might be pricy, but if you use ticket management, documentation (instead of, e.g. Jira), roadmap tooling, release notes management, Terrafrom stage seems like a no-brainer!

Challenges you might hit when growing:

• Pipeline deployment ordering as parallel pipelines run
• Shared runners are small machines step to registered add admin infra work
• A security model is similar to Spinnaker, additionally doesn’t allow custom groups, but I guess that you can create custom apps (users)
• Pricing seems scary at the end runners probably run on your infra and registered to the platform, OTOH if managed to keep on shared runners, need to buy a lot of build minutes. 
• Storage cost seems high 
• Docker registry has 30 days expiry (probably can be extended) => you will be uploading to your GCR

I haven’t studied in deep deployment capabilities:

• Integration with Helm – probably rendering via helm template and then deploy
• Support for deployment strategies – requires appropriate kubernetes object manifests as everywhere
• Registered kubernetes seems to have an agent running in them
• Has all concepts from Spinnaker more less
• Has starting support for Terraform in alpha

GitLab Potential pain points:

• Having a whole pipeline in git(including deployment strategies configurations, approvals) – might pose challenges when there is no pure trunk-based development – requires a need for backporting and harder for surveillance. 

GitLab is built on top of plenty of OS projects where I can imagine that integration between your infrastructure and GL might be extensive.

The only reasonable scenario that you fully migrate to GitLab and reduce extra tooling like Assana, GitHub, Confluence, … or for new projects that might be a no-brainer. That migration can be pretty heavy, but you might get some compliance checks for that in a single workspace. 

Resources for more detail GitLab overview

• Product overview
• Complex configuration and data management