Own Service Accounts¶

Problem Description¶

Currently when an OpenStack-Helm chart deploys a OpenStack service, it creates a service account that is used by other Openstack services to interact with the service’s API. For example, the Nova chart creates a service account called nova and other charts like Cinder and Neutron configure Cinder and Neutron services to use the nova service account to interact with the Nova API.

However, there might be scenarios where multiple Nova accounts are necessary. For instance, if Neutron requires more permissive access to the Nova API than Cinder, it might be desirable to create two separate accounts with tailored permissions.

Also the current approach assumes service accounts are owned by the chart that creates them and it requires other charts to be deployed with the credentials of the service account owner chart. I.e. the service account credentials must be synced between charts.

Proposed Change¶

The spec proposes to modify the Keystone user manifest so it is able to create multiple Keystone users. The job will be deployed with multiple containers, each container will create a separate Keystone user.

All other Openstack charts use the Keystone user manifest for managing service accounts. So every Openstack chart will be able to create a bunch of service accounts according to their needs.

E.g. the Neutron chart will create the following service accounts:

neutron (used by Neutron to communicate with the Keystone API to check auth tokens and other services can use it to get access to the Neutron API)
neutron_nova (used by Neutron to get access to the Nova API instead of using nova service account created by the Nova chart)
neutron_placement (used by Neutron to get access to the Placement API instead of using placement service account managed by the Placement chart)

The proposed change is going to be backward compatible because the Neutron chart will still be able to use the neutron and placement service accounts managed by the Nova and Placement charts. Also the neutron service account can still be used by other charts to communicate with the Neutron API.

Implementation¶

Assignee(s)¶

Primary assignee:: kozhukalov (Vladimir Kozhukalov <kozhukalov@gmail.com>)

Values¶

Service accounts credentials are defined in the values.yaml files in the .Values.endpoints.identity.auth section. The section contains a bunch of dicts defining credentials for every service account.

Currently those dicts which correspond to service accounts managed by other charts must be aligned with those charts values. For example, the Neutron values must define the nova service account the same way as the Nova chart does.

The following is the example of how the .Values.endpoints.identity.auth section of a chart must be modified. The example is given for the Neutron chart:

endpoints:
  identity:
    auth:
      # This serivce account is managed by Keystone chart
      # and created during Keystone database sync.
      # We should not modify it.
      admin:
        region_name: RegionOne
        username: admin
        password: password
        project_name: admin
        user_domain_name: default
        project_domain_name: default
      # Service account with the following username/password
      # will be created by the Keystone user job
      # and will be used for Neutron configuration.
      # For backward compatibility this dict must not be modified
      # to stay aligned with other charts that use this service account
      # to get access to the Neutron API.
      neutron:
        role: admin,service
        region_name: RegionOne
        username: neutron
        password: password
        project_name: service
        user_domain_name: service
        project_domain_name: service
      # Service account with the following username/password
      # will be created by the Keystone user job
      # and will be used for Neutron configuration. Also the
      # `role` field must be added to assign necessary roles
      # to the service account.
      nova:
        role: admin,service
        region_name: RegionOne
        project_name: service
        username: neutron_nova
        password: neutron_nova_password
        user_domain_name: service
        project_domain_name: service
      # Service account with the following username/password
      # will be created by the Keystone user job
      # and will be used for Neutron configuration. Also the
      # `role` field must be added to assign necessary roles
      # to the service account.
      placement:
        role: admin,service
        region_name: RegionOne
        project_name: service
        username: neutron_placement
        password: neutron_placement_password
        user_domain_name: service
        project_domain_name: service

Secrets¶

The service account credentials are stored in K8s secrets which are used by the Keystone user manifest to create the service accounts.

So the the template that deploys those secrets must be updated to create the secrets for all service accounts defined in the .Values.endpoints.identity.auth section.

Also the .Values.secrets.identity section must be updated and secret names must be added for all service accounts defined in the .Values.endpoints.identity.auth section.

Keystone user manifest¶

The Helm-toolkit chart defines the Keystone user manifest which is used by all Openstack charts to create service accounts. The manifest must be updated to be able to accept serviceUsers parameter which will be the list of service accounts to be created by the job.

For backward compatibility if the serviceUsers parameter is not given then the manifest will use the serviceUser parameter or serviceName parameter to define the serviceUsers as a list with a single element.

{{- $serviceName := index . "serviceName" -}}
{{- $singleServiceUser := index . "serviceUser" | default $serviceName -}}
{{- $serviceUsers := index . "serviceUsers" | default (tuple $singleServiceUser) -}}

Keystone user job¶

All Openstack charts deploy the job to create service accounts which uses the Keystone user manifest. The modified manifest will be able to create multiple Keystone users and the job template must also be updated to pass the proper list of service accounts to the manifest.

For example, the Neutron chart will be modified to create the following service accounts:

{{ dict "envAll" . "serviceName" "neutron" "serviceUsers" (tuple "neutron" "nova" "placement") | include "helm-toolkit.manifests.job_ks_user" }}

Work Items¶

Modify the Keystone user manifest to make it possible to create multiple Keystone users in a single job.
Modify charts one by one as described above so they create their own service accounts to get access to the APIs of other OpenStack services.

Alternatives¶

A K8s operator can be used to manage service accounts. In this case charts will deploy the custom resources that will be handled by the operator. The operator could also be useful for more complex scenarios when users deploy Keystone federation and need more flexibility in managing service accounts.

However, the proposed change is simpler to implement and it does not require any additional components while the change is backward compatible and does not break existing deployments.

Documentation Impact¶

The documentation must be updated to reflect the change.

Own Service Accounts