Service accounts provide a flexible way to control API access without sharing a regular user’s credentials.
Every service account has an associated user name that can be granted roles, just like a regular user. The user name is derived from its project and name:
system:serviceaccount:<project>:<name>
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
Every service account is also a member of two groups:
- system:serviceaccounts
-
Includes all service accounts in the system.
- system:serviceaccounts:<project>
-
Includes all service accounts in the specified project.
For example, to allow all service accounts in all projects to view resources in the top-secret project:
$ oc policy add-role-to-group view system:serviceaccounts -n top-secret
To allow all service accounts in the managers project to edit resources in the top-secret project:
$ oc policy add-role-to-group edit system:serviceaccounts:managers -n top-secret
As soon as a service account is created, two secrets are automatically added to it:
-
an API token
-
credentials for the
These can be seen by describing the service account:
$ oc describe sa robot Name: robot Namespace: project1 Labels: <none> Annotations: <none> Image pull secrets: robot-dockercfg-qzbhb Mountable secrets: robot-token-f4khf robot-dockercfg-qzbhb Tokens: robot-token-f4khf robot-token-z8h44
The system ensures that service accounts always have an API token and registry credentials.
The generated API token and registry credentials do not expire, but they can be revoked by deleting the secret. When the secret is deleted, a new one is automatically generated to take its place.
Service accounts authenticate to the API using tokens signed by a private RSA key. The authentication layer verifies the signature using a matching public RSA key.
To enable service account token generation, update the serviceAccountConfig
stanza in the /etc/origin/master/master-config.yml file on the master to
specify a privateKeyFile
(for signing), and a matching public key file in
the publicKeyFiles
list:
serviceAccountConfig: ... masterCA: ca.crt (1) privateKeyFile: serviceaccounts.private.key (2) publicKeyFiles: - serviceaccounts.public.key (3) - ...
-
CA file used to validate the API server’s serving certificate.
-
Private RSA key file (for token signing).
-
Public RSA key files (for token verification). If private key files are provided, then the public key component is used. Multiple public key files can be specified, and a token will be accepted if it can be validated by one of the public keys. This allows rotation of the signing key, while still accepting tokens generated by the previous signer.