How to unify CI/CD for dozens of repositories from different teams in GitLab? How to manage this alone?

To standardize CI/CD across dozens of repositories of different teams in GitLab and manage it alone, you can:

1. Create pipeline templates: Extract common stages and steps into .gitlab-ci.yml templates or include files that will be connected in each repository.

2. Use GitLab CI/CD Includes: Allows connecting common configurations from a central repository, simplifying updates and maintenance.

3. Define standards and documentation: Clearly describe the requirements for the pipeline, naming conventions, mandatory checks.

4. Automate updates: You can write scripts or use the GitLab API for mass updating .gitlab-ci.yml in repositories.

5. Use variables and templates: For parameterizing the pipeline for different projects.

6. Monitoring and notifications: Set up centralized monitoring of build statuses and notifications.

Example of connecting a common template in .gitlab-ci.yml:

include:
  - project: 'group/ci-templates'
    file: '/templates/common.yml'

stages:
  - build
  - test
  - deploy

build_job:
  stage: build
  script:
    - ./build.sh

Thus, centralized management of templates and standardization allow effectively maintaining many CI/CD pipelines even by a single person.