Connect to cloud services

Version history
  • CI_JOB_JWT variable for reading secrets from Vault introduced in GitLab 12.10.
  • CI_JOB_JWT_V2 variable to support additional OIDC providers introduced in GitLab 14.7.

GitLab CI/CD supports OpenID Connect (OIDC) that allows your build and deployment job access to cloud credentials and services. Historically, teams stored secrets in projects or applied permissions on the GitLab Runner instance to build and deploy. To support this, a predefined variable named CI_JOB_JWT_V2 is included in the CI/CD job allowing you to follow a scalable and least-privilege security approach.

Requirements

  • Account on GitLab.
  • Access to a cloud provider that supports OIDC to configure authorization and create roles.

The original implementation of CI_JOB_JWT supports HashiCorp Vault integration. The updated implementation of CI_JOB_JWT_V2 supports additional cloud providers with OIDC including AWS, GCP, and Vault.

caution
The CI_JOB_JWT_V2 variable is under development (alpha) and is not yet suitable for production use.

Use cases

  • Removes the need to store secrets in your GitLab group or project. Temporary credentials can be retrieved from your cloud provider through OIDC.
  • Provides temporary access to cloud resources with granular GitLab conditionals including a group, project, branch, or tag.
  • Enables you to define separation of duties in the CI/CD job with conditional access to environments. Historically, apps may have been deployed with a designated GitLab Runner that had only access to staging or production environments. This led to Runner sprawl as each machine had dedicated permissions.
  • Allows shared runners to securely access multiple cloud accounts. The access is determined by the JWT token, which is specific to the user running the pipeline.
  • Removes the need to create logic to rotate secrets by retrieving temporary credentials by default.

How it works

Each job has a JSON web token (JWT) provided as a CI/CD predefined variable named CI_JOB_JWT or CI_JOB_JWT_V2. This JWT can be used to authenticate with the OIDC-supported cloud provider such as AWS, GCP, or Vault.

The following fields are included in the JWT:

Field When Description
jti Always Unique identifier for this token
iss Always Issuer, the domain of your GitLab instance
iat Always Issued at
nbf Always Not valid before
exp Always Expires at
aud Always Issuer, the domain of your GitLab instance
sub Always project_path:{group}/{project}:ref_type:{type}:ref:{branch_name}
namespace_id Always Use this to scope to group or user level namespace by ID
namespace_path Always Use this to scope to group or user level namespace by path
project_id Always Use this to scope to project by ID
project_path Always Use this to scope to project by path
user_id Always ID of the user executing the job
user_login Always Username of the user executing the job
user_email Always Email of the user executing the job
pipeline_id Always ID of this pipeline
pipeline_source Always Pipeline source
job_id Always ID of this job
ref Always Git ref for this job
ref_type Always Git ref type, either branch or tag
ref_protected Always true if this Git ref is protected, false otherwise
environment Job is creating a deployment Environment this job deploys to (introduced in GitLab 13.9)
environment_protected Job is creating a deployment true if deployed environment is protected, false otherwise (introduced in GitLab 13.9)
{
  "jti": "c82eeb0c-5c6f-4a33-abf5-4c474b92b558",
  "iss": "https://gitlab.example.com",
  "aud": "https://gitlab.example.com",
  "iat": 1585710286,
  "nbf": 1585798372,
  "exp": 1585713886,
  "sub": "project_path:mygroup/myproject:ref_type:branch:ref:main",
  "namespace_id": "1",
  "namespace_path": "mygroup",
  "project_id": "22",
  "project_path": "mygroup/myproject",
  "user_id": "42",
  "user_login": "myuser",
  "user_email": "myuser@example.com",
  "pipeline_id": "1212",
  "pipeline_source": "web",
  "job_id": "1212",
  "ref": "auto-deploy-2020-04-01",
  "ref_type": "branch",
  "ref_protected": "true",
  "environment": "production",
  "environment_protected": "true"
}

Authorization workflow

sequenceDiagram participant GitLab Note right of Cloud: Create OIDC identity provider Note right of Cloud: Create role with conditionals Note left of GitLab: CI/CD job with CI_JOB_JWT_V2 GitLab->>+Cloud: Call cloud API with CI_JOB_JWT_V2 Note right of Cloud: Decode & verify JWT with public key (https://gitlab/-/jwks) Note right of Cloud: Validate audience defined in OIDC Note right of Cloud: Validate conditional (sub, aud) role Note right of Cloud: Generate credential or fetch secret Cloud->>GitLab: Return temporary credential Note left of GitLab: Perform operation
  1. Create an OIDC identity provider in the cloud (for example, AWS, GCP, Vault).
  2. Create a conditional role in the cloud service that filters to a group, project, branch, or tag.
  3. The CI/CD job includes a predefined variable CI_JOB_JWT_V2 that is a JWT token. You can use this token for authorization with your cloud API.
  4. The cloud verifies the token, validates the conditional role from the payload, and returns a temporary credential.

Configure a conditional role with OIDC claims

To configure the trust between GitLab and OIDC, you must create a conditional role in the cloud provider that checks against the JWT token. The condition is validated against the JWT to create a trust specifically against two claims, the audience and subject.

  • Audience or aud: The URL of the GitLab instance. This is defined when the identity provider is first configured in your cloud provider.
  • Subject or sub: A concatenation of metadata describing the GitLab CI/CD workflow including the group, project, branch, and tag. The sub field is in the following format:
    • project_path:{group}/{project}:ref_type:{type}:ref:{branch_name}
Filter type Example
Filter to main branch project_path:mygroup/myproject:ref_type:branch:ref:main
Filter to any branch Wildcard supported. project_path:mygroup/myproject:ref_type:branch:ref:*
Filter to specific project project_path:mygroup/myproject:ref_type:branch:ref:main
Filter to all projects under a group Wildcard supported. project_path:mygroup/*:ref_type:branch:ref:main
Filter to a Git tag Wildcard supported. project_path:mygroup/*:ref_type:tag:ref:1.0

OIDC authorization with your cloud provider

To connect with your cloud provider, see the following tutorials: