Merge branch 'oidc_cloud_services_aws' into 'master'

Documentation of OIDC with AWS

See merge request gitlab-org/gitlab!77127

doc/ci/cloud_services/aws/index.md

+---
+stage: Configure
+group: Configure
+info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments
+---
+
+# Configure OpenID Connect in AWS to retrieve temporary credentials
+
+In this tutorial, we'll show you how to use a GitLab CI/CD job with a JSON web token (JWT) to retrieve temporary credentials from AWS without needing to store secrets.
+To do this, you must configure OpenID Connect (OIDC) for ID federation between GitLab and AWS. For background and requirements for integrating GitLab using OIDC, see [Connect to cloud services](../index.md).
+
+To complete this tutorial:
+
+1. [Add the identity provider](#add-the-identity-provider)
+1. [Configure the role and trust](#configure-a-role-and-trust)
+1. [Retrieve a temporary credential](#retrieve-temporary-credentials)
+
+## Add the identity provider
+
+Create GitLab as a IAM OIDC provider in AWS following these [instructions](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_providers_create_oidc.html).
+
+Include the following information:
+
+- **Provider URL**: The address of your GitLab instance, such as `https://gitlab.com` or `http://gitlab.example.com`. 
+- **Audience**: The address of your GitLab instance, such as `https://gitlab.com` or `http://gitlab.example.com`. 
+  - The address must include `https://`.
+  - Do not include a trailing slash.
+
+## Configure a role and trust
+
+After you create the identity provider, configure a [web identity role](https://docs.aws.amazon.com/IAM/latest/UserGuide/id_roles_create_for-idp_oidc.html) with conditions for limiting access to GitLab resources. Temporary credentials are obtained using [AWS Security Token Service](https://docs.aws.amazon.com/STS/latest/APIReference/welcome.html), so set the `Action` to [sts:AssumeRoleWithWebIdentity](https://docs.aws.amazon.com/STS/latest/APIReference/API_AssumeRoleWithWebIdentity.html).
+
+For the full list of supported filtering types, see [Connect to cloud services](../index.md).
+
+```json
+{
+  "Version": "2012-10-17",
+  "Statement": [
+    {
+      "Effect": "Allow",
+      "Principal": {
+        "Federated": "arn:aws:iam::AWS_ACCOUNT:oidc-provider/gitlab.example.com"
+      },
+      "Action": "sts:AssumeRoleWithWebIdentity",
+      "Condition": {
+        "StringEquals": {
+          "gitlab.example.com:sub": "project_path:mygroup/myproject:ref_type:branch:ref:main"
+        }
+      }
+    }
+  ]
+}
+```
+
+After the role is created, attach a policy defining permissions to an AWS service (S3, EC2, Secrets Manager).
+
+## Retrieve temporary credentials
+
+After you configure the OIDC and role, the GitLab CI/CD job can retrieve a temporary credential from [AWS Security Token Service (STS)](https://docs.aws.amazon.com/STS/latest/APIReference/welcome.html). 
+
+```yaml
+assume role:
+  script:
+    - >
+      STS=($(aws sts assume-role-with-web-identity
+      --role-arn ${ROLE_ARN}
+      --role-session-name "GitLabRunner-${CI_PROJECT_ID}-${CI_PIPELINE_ID}"
+      --web-identity-token $CI_JOB_JWT_V2
+      --duration-seconds 3600
+      --query 'Credentials.[AccessKeyId,SecretAccessKey,SessionToken]'
+      --output text))
+    - export AWS_ACCESS_KEY_ID="${STS[0]}"
+    - export AWS_SECRET_ACCESS_KEY="${STS[1]}"
+    - export AWS_SESSION_TOKEN="${STS[2]}"
+    - aws sts get-caller-identity
+```
+
+- `CI_JOB_JWT_V2`: Predefined variable.
+- `ROLE_ARN`: The role ARN defined in this [step](#configure-a-role-and-trust).
+
+## Working example 
+
+See this [reference project](https://gitlab.com/guided-explorations/aws/configure-openid-connect-in-aws) for provisioning OIDC in AWS using Terraform and a sample script to retrieve temporary credentials.
+
+## Troubleshooting
+
+### `An error occurred (AccessDenied) when calling the AssumeRoleWithWebIdentity operation: Not authorized to perform sts:AssumeRoleWithWebIdentity`
+
+This error can occur for multiple reasons:
+
+- The cloud administrator has not configured the project to use OIDC with GitLab.
+- The role is restricted from being run on the branch or tag. See [configure a conditional role](../index.md).

doc/install/aws/index.md

@@ -43,6 +43,7 @@ The following repository is self-contained in regard to enabling this pattern: [
 
 - Using GitLab and AWS together.
 - Running GitLab infrastructure on AWS.
+- Retrieving temporary credentials for access to AWS services.
 
 ## AWS known issues list