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Understanding and creating service accounts | Authentication and authorization | OKD 4.11
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Understanding and creating service accounts

Service accounts overview

A service account is an OKD account that allows a component to directly access the API. Service accounts are API objects that exist within each project. Service accounts provide a flexible way to control API access without sharing a regular user’s credentials.

When you use the OKD CLI or web console, your API token authenticates you to the API. You can associate a component with a service account so that they can access the API without using a regular user’s credentials. For example, service accounts can allow:

  • Replication controllers to make API calls to create or delete pods.

  • Applications inside containers to make API calls for discovery purposes.

  • External applications to make API calls for monitoring or integration purposes.

Each service account’s user name is derived from its project and name:

system:serviceaccount:<project>:<name>

Every service account is also a member of two groups:

Group Description

system:serviceaccounts

Includes all service accounts in the system.

system:serviceaccounts:<project>

Includes all service accounts in the specified project.

Each service account automatically contains two secrets:

  • An API token

  • Credentials for the OpenShift Container Registry

The generated API token and registry credentials do not expire, but you can revoke them by deleting the secret. When you delete the secret, a new one is automatically generated to take its place.

Creating service accounts

You can create a service account in a project and grant it permissions by binding it to a role.

Procedure

  1. Optional: To view the service accounts in the current project:

    $ oc get sa
    Example output
    NAME       SECRETS   AGE
builder    2         2d
default    2         2d
deployer   2         2d

  2. To create a new service account in the current project:

    $ oc create sa <service_account_name> (1)
    1 To create a service account in a different project, specify -n <project_name>.
    Example output
    serviceaccount "robot" created

    You can alternatively apply the following YAML to create the service account:

    apiVersion: v1
kind: ServiceAccount
metadata:
  name: <service_account_name>
  namespace: <current_project>

  3. Optional: View the secrets for the service account:

    $ oc describe sa robot
    Example output
    Name:                robot
Namespace:           project1
Labels:	             <none>
Annotations:	     <none>
Image pull secrets:  robot-dockercfg-qzbhb
Mountable secrets:   robot-dockercfg-qzbhb
Tokens:              robot-token-f4khf
Events:              <none>

Examples of granting roles to service accounts

You can grant roles to service accounts in the same way that you grant roles to a regular user account.

  • You can modify the service accounts for the current project. For example, to add the view role to the robot service account in the top-secret project:

    $ oc policy add-role-to-user view system:serviceaccount:top-secret:robot

    You can alternatively apply the following YAML to add the role:

    apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: view
  namespace: top-secret
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: view
subjects:
- kind: ServiceAccount
  name: robot
  namespace: top-secret

  • You can also grant access to a specific service account in a project. For example, from the project to which the service account belongs, use the -z flag and specify the <service_account_name>

    $ oc policy add-role-to-user <role_name> -z <service_account_name>

    If you want to grant access to a specific service account in a project, use the -z flag. Using this flag helps prevent typos and ensures that access is granted to only the specified service account.

    You can alternatively apply the following YAML to add the role:

    apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: <rolebinding_name>
  namespace: <current_project_name>
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: <role_name>
subjects:
- kind: ServiceAccount
  name: <service_account_name>
  namespace: <current_project_name>

  • To modify a different namespace, you can use the -n option to indicate the project namespace it applies to, as shown in the following examples.

    • For example, to allow all service accounts in all projects to view resources in the my-project project:

      $ oc policy add-role-to-group view system:serviceaccounts -n my-project

      You can alternatively apply the following YAML to add the role:

      apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: view
  namespace: my-project
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: view
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: Group
  name: system:serviceaccounts

    • To allow all service accounts in the managers project to edit resources in the my-project project:

      $ oc policy add-role-to-group edit system:serviceaccounts:managers -n my-project

      You can alternatively apply the following YAML to add the role:

      apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: edit
  namespace: my-project
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: edit
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: Group
  name: system:serviceaccounts:managers