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Chapter 10. Understanding and creating service accounts
10.1. Service accounts overview
A service account is an OpenShift Container Platform 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 OpenShift Container Platform 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.
10.2. Creating service accounts
You can create a service account in a project and grant it permissions by binding it to a role.
Procedure
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
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
TipYou can alternatively apply the following YAML to create the service account:
apiVersion: v1 kind: ServiceAccount metadata: name: <service_account_name> namespace: <current_project>
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>
10.3. 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
viewrole to therobotservice account in thetop-secretproject:$ oc policy add-role-to-user view system:serviceaccount:top-secret:robot
TipYou 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
-zflag and specify the<service_account_name>$ oc policy add-role-to-user <role_name> -z <service_account_name>
ImportantIf you want to grant access to a specific service account in a project, use the
-zflag. Using this flag helps prevent typos and ensures that access is granted to only the specified service account.TipYou 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
-noption 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-projectproject:$ oc policy add-role-to-group view system:serviceaccounts -n my-project
TipYou 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
managersproject to edit resources in themy-projectproject:$ oc policy add-role-to-group edit system:serviceaccounts:managers -n my-project
TipYou 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
