Understanding and creating service accounts | Authentication

Service accounts overview
Creating service accounts
Examples of granting roles to service accounts

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:

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

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

$ oc get sa

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)

serviceaccount "robot" created
```
1 To create a service account in a different project, specify -n <project_name>.

Optional: View the secrets for 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

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 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 <serviceaccount_name>

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

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 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