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Using manual mode with Amazon Web Services Secure Token Service

About manual mode with AWS Secure Token Service

In manual mode with STS, the individual OpenShift Container Platform cluster components use AWS Secure Token Service (STS) to assign components IAM roles that provide short-term, limited-privilege security credentials. These credentials are associated with IAM roles that are specific to each component that makes AWS API calls.

Requests for new and refreshed credentials are automated by using an appropriately configured AWS IAM OpenID Connect (OIDC) identity provider, combined with AWS IAM roles. OpenShift Container Platform signs service account tokens that are trusted by AWS IAM, and can be projected into a pod and used for authentication. Tokens are refreshed after one hour.

Detailed authentication flow between AWS and the cluster when using AWS STS
Figure 1. STS authentication flow

Using manual mode with STS changes the content of the AWS credentials that are provided to individual OpenShift Container Platform components.

AWS secret format using long-lived credentials
apiVersion: v1
kind: Secret
metadata:
  namespace: <target-namespace> (1)
  name: <target-secret-name> (2)
data:
  aws_access_key_id: <base64-encoded-access-key-id>
  aws_secret_access_key: <base64-encoded-secret-access-key>
1 The namespace for the component.
2 The name of the component secret.
AWS secret format with STS
apiVersion: v1
kind: Secret
metadata:
  namespace: <target-namespace> (1)
  name: <target-secret-name> (2)
stringData:
  credentials: |-
    [default]
    role_name: <operator-role-name> (3)
    web_identity_token_file: <path-to-token> (4)
1 The namespace for the component.
2 The name of the component secret.
3 The IAM role for the component.
4 The path to the service account token inside the pod. By convention, this is /var/run/secrets/openshift/serviceaccount/token for OpenShift Container Platform components.

Installing an OpenShift Container Platform cluster configured for manual mode with STS

To install a cluster that is configured to use the Cloud Credential Operator (CCO) in manual mode with STS:

  1. Configure the Cloud Credential Operator utility.

  2. Create the required AWS resources individually, or with a single command.

  3. Run the OpenShift Container Platform installer.

  4. Verify that the cluster is using short-lived credentials.

Because the cluster is operating in manual mode when using STS, it is not able to create new credentials for components with the permissions that they require. When upgrading to a different minor version of OpenShift Container Platform, there are often new AWS permission requirements. Before upgrading a cluster that is using STS, the cluster administrator must manually ensure that the AWS permissions are sufficient for existing components and available to any new components.

Configuring the Cloud Credential Operator utility

To create and manage cloud credentials from outside of the cluster when the Cloud Credential Operator (CCO) is operating in manual mode with STS, extract and prepare the CCO utility (ccoctl) binary.

The ccoctl is a Linux binary that must run in a Linux environment.
Prerequisites

  • You have created an AWS account for the ccoctl to use with the following permissions:

    Table 1. Required AWS permissions
    iam permissions s3 permissions

    • iam:CreateOpenIDConnectProvider

    • iam:CreateRole

    • iam:DeleteOpenIDConnectProvider

    • iam:DeleteRole

    • iam:DeleteRolePolicy

    • iam:GetOpenIDConnectProvider

    • iam:GetRole

    • iam:GetUser

    • iam:ListOpenIDConnectProviders

    • iam:ListRolePolicies

    • iam:ListRoles

    • iam:PutRolePolicy

    • iam:TagOpenIDConnectProvider

    • iam:TagRole

    • s3:CreateBucket

    • s3:DeleteBucket

    • s3:DeleteObject

    • s3:GetBucketAcl

    • s3:GetBucketTagging

    • s3:GetObject

    • s3:GetObjectAcl

    • s3:GetObjectTagging

    • s3:ListBucket

    • s3:PutBucketAcl

    • s3:PutBucketTagging

    • s3:PutObject

    • s3:PutObjectAcl

    • s3:PutObjectTagging
Procedure

  1. Obtain the OpenShift Container Platform release image by running the following command:

    $ RELEASE_IMAGE=$(./openshift-install version | awk '/release image/ {print $3}')

  2. Get the CCO container image from the OpenShift Container Platform release image by running the following command:

    $ CCO_IMAGE=$(oc adm release info --image-for='cloud-credential-operator' $RELEASE_IMAGE)

    Ensure that the architecture of the $RELEASE_IMAGE matches the architecture of the environment in which you will use the ccoctl tool.

  3. Extract the ccoctl binary from the CCO container image within the OpenShift Container Platform release image by running the following command:

    $ oc image extract $CCO_IMAGE --file="/usr/bin/ccoctl" -a ~/.pull-secret

  4. Change the permissions to make ccoctl executable by running the following command:

    $ chmod 775 ccoctl
Verification

  • To verify that ccoctl is ready to use, display the help file by running the following command:

    $ ccoctl --help
    Output of ccoctl --help:
    OpenShift credentials provisioning tool

Usage:
  ccoctl [command]

Available Commands:
  alibabacloud Manage credentials objects for alibaba cloud
  aws          Manage credentials objects for AWS cloud
  gcp          Manage credentials objects for Google cloud
  help         Help about any command
  ibmcloud     Manage credentials objects for IBM Cloud
  nutanix      Manage credentials objects for Nutanix

Flags:
  -h, --help   help for ccoctl

Use "ccoctl [command] --help" for more information about a command.

Creating AWS resources with the Cloud Credential Operator utility

You can use the CCO utility (ccoctl) to create the required AWS resources individually, or with a single command.

Creating AWS resources individually

If you need to review the JSON files that the ccoctl tool creates before modifying AWS resources, or if the process the ccoctl tool uses to create AWS resources automatically does not meet the requirements of your organization, you can create the AWS resources individually. For example, this option might be useful for an organization that shares the responsibility for creating these resources among different users or departments.

Otherwise, you can use the ccoctl aws create-all command to create the AWS resources automatically.

By default, ccoctl creates objects in the directory in which the commands are run. To create the objects in a different directory, use the --output-dir flag. This procedure uses <path_to_ccoctl_output_dir> to refer to this directory.

Some ccoctl commands make AWS API calls to create or modify AWS resources. You can use the --dry-run flag to avoid making API calls. Using this flag creates JSON files on the local file system instead. You can review and modify the JSON files and then apply them with the AWS CLI tool using the --cli-input-json parameters.
Prerequisites

  • Extract and prepare the ccoctl binary.

Procedure

  1. Generate the public and private RSA key files that are used to set up the OpenID Connect provider for the cluster:

    $ ccoctl aws create-key-pair
    Example output:
    2021/04/13 11:01:02 Generating RSA keypair
2021/04/13 11:01:03 Writing private key to /<path_to_ccoctl_output_dir>/serviceaccount-signer.private
2021/04/13 11:01:03 Writing public key to /<path_to_ccoctl_output_dir>/serviceaccount-signer.public
2021/04/13 11:01:03 Copying signing key for use by installer

    where serviceaccount-signer.private and serviceaccount-signer.public are the generated key files.

    This command also creates a private key that the cluster requires during installation in /<path_to_ccoctl_output_dir>/tls/bound-service-account-signing-key.key.

  2. Create an OpenID Connect identity provider and S3 bucket on AWS:

    $ ccoctl aws create-identity-provider \
--name=<name> \
--region=<aws_region> \
--public-key-file=<path_to_ccoctl_output_dir>/serviceaccount-signer.public

    where:

    • <name> is the name used to tag any cloud resources that are created for tracking.

    • <aws-region> is the AWS region in which cloud resources will be created.

    • <path_to_ccoctl_output_dir> is the path to the public key file that the ccoctl aws create-key-pair command generated.

    Example output:
    2021/04/13 11:16:09 Bucket <name>-oidc created
2021/04/13 11:16:10 OpenID Connect discovery document in the S3 bucket <name>-oidc at .well-known/openid-configuration updated
2021/04/13 11:16:10 Reading public key
2021/04/13 11:16:10 JSON web key set (JWKS) in the S3 bucket <name>-oidc at keys.json updated
2021/04/13 11:16:18 Identity Provider created with ARN: arn:aws:iam::<aws_account_id>:oidc-provider/<name>-oidc.s3.<aws_region>.amazonaws.com

    where 02-openid-configuration is a discovery document and 03-keys.json is a JSON web key set file.

    This command also creates a YAML configuration file in /<path_to_ccoctl_output_dir>/manifests/cluster-authentication-02-config.yaml. This file sets the issuer URL field for the service account tokens that the cluster generates, so that the AWS IAM identity provider trusts the tokens.

  3. Create IAM roles for each component in the cluster.

    1. Extract the list of CredentialsRequest objects from the OpenShift Container Platform release image:

      $ oc adm release extract --credentials-requests \
--cloud=aws \
--to=<path_to_directory_with_list_of_credentials_requests>/credrequests (1)
--from=quay.io/<path_to>/ocp-release:<version>
      1 credrequests is the directory where the list of CredentialsRequest objects is stored. This command creates the directory if it does not exist.

    2. Use the ccoctl tool to process all CredentialsRequest objects in the credrequests directory:

      $ ccoctl aws create-iam-roles \
--name=<name> \
--region=<aws_region> \
--credentials-requests-dir=<path_to_directory_with_list_of_credentials_requests>/credrequests \
--identity-provider-arn=arn:aws:iam::<aws_account_id>:oidc-provider/<name>-oidc.s3.<aws_region>.amazonaws.com

      For AWS environments that use alternative IAM API endpoints, such as GovCloud, you must also specify your region with the --region parameter.

      If your cluster uses Technology Preview features that are enabled by the TechPreviewNoUpgrade feature set, you must include the --enable-tech-preview parameter.

      For each CredentialsRequest object, ccoctl creates an IAM role with a trust policy that is tied to the specified OIDC identity provider, and a permissions policy as defined in each CredentialsRequest object from the OpenShift Container Platform release image.

Verification

  • To verify that the OpenShift Container Platform secrets are created, list the files in the <path_to_ccoctl_output_dir>/manifests directory:

    $ ll <path_to_ccoctl_output_dir>/manifests
    Example output:
    total 24
-rw-------. 1 <user> <user> 161 Apr 13 11:42 cluster-authentication-02-config.yaml
-rw-------. 1 <user> <user> 379 Apr 13 11:59 openshift-cloud-credential-operator-cloud-credential-operator-iam-ro-creds-credentials.yaml
-rw-------. 1 <user> <user> 353 Apr 13 11:59 openshift-cluster-csi-drivers-ebs-cloud-credentials-credentials.yaml
-rw-------. 1 <user> <user> 355 Apr 13 11:59 openshift-image-registry-installer-cloud-credentials-credentials.yaml
-rw-------. 1 <user> <user> 339 Apr 13 11:59 openshift-ingress-operator-cloud-credentials-credentials.yaml
-rw-------. 1 <user> <user> 337 Apr 13 11:59 openshift-machine-api-aws-cloud-credentials-credentials.yaml

You can verify that the IAM roles are created by querying AWS. For more information, refer to AWS documentation on listing IAM roles.

Creating AWS resources with a single command

If you do not need to review the JSON files that the ccoctl tool creates before modifying AWS resources, and if the process the ccoctl tool uses to create AWS resources automatically meets the requirements of your organization, you can use the ccoctl aws create-all command to automate the creation of AWS resources.

Otherwise, you can create the AWS resources individually.

By default, ccoctl creates objects in the directory in which the commands are run. To create the objects in a different directory, use the --output-dir flag. This procedure uses <path_to_ccoctl_output_dir> to refer to this directory.
Prerequisites

You must have:

  • Extracted and prepared the ccoctl binary.

Procedure

  1. Extract the list of CredentialsRequest objects from the OpenShift Container Platform release image:

    $ oc adm release extract \
--credentials-requests \
--cloud=aws \
--to=<path_to_directory_with_list_of_credentials_requests>/credrequests \ (1)
--from=quay.io/<path_to>/ocp-release:<version>
    1 credrequests is the directory where the list of CredentialsRequest objects is stored. This command creates the directory if it does not exist.

    This command can take a few moments to run.

  2. Use the ccoctl tool to process all CredentialsRequest objects in the credrequests directory:

    $ ccoctl aws create-all \
--name=<name> \
--region=<aws_region> \
--credentials-requests-dir=<path_to_directory_with_list_of_credentials_requests>/credrequests

    where:

    • <name> is the name used to tag any cloud resources that are created for tracking.

    • <aws_region> is the AWS region in which cloud resources will be created.

    • <path_to_directory_with_list_of_credentials_requests>/credrequests is the directory containing the files for the component CredentialsRequest objects.

    If your cluster uses Technology Preview features that are enabled by the TechPreviewNoUpgrade feature set, you must include the --enable-tech-preview parameter.
Verification

  • To verify that the OpenShift Container Platform secrets are created, list the files in the <path_to_ccoctl_output_dir>/manifests directory:

    $ ls <path_to_ccoctl_output_dir>/manifests
    Example output:
    cluster-authentication-02-config.yaml
openshift-cloud-credential-operator-cloud-credential-operator-iam-ro-creds-credentials.yaml
openshift-cluster-csi-drivers-ebs-cloud-credentials-credentials.yaml
openshift-image-registry-installer-cloud-credentials-credentials.yaml
openshift-ingress-operator-cloud-credentials-credentials.yaml
openshift-machine-api-aws-cloud-credentials-credentials.yaml

You can verify that the IAM roles are created by querying AWS. For more information, refer to AWS documentation on listing IAM roles.