Policy Guided Fulfillment - Policy Enforcement Point

URL of launchpad blueprint:


Problem description

As a part of policy guided fulfillment we need to implement predeploy policy enforcement point - i.e., Murano calls Congress to evaluate predeploy policy rules on data representing Murano environment being deployed. If evaluation returns predeploy error data (i.e., enforcement failed), then deployment of Murano environment fails.

Predeploy policy rules are represented by predeploy_error(env_id, obj_id, message) congress table. It means

  • Congress administrator is responsible for creating predeploy rules, which has this table on the left side (see examples).
  • Murano is not involved in policy rule evaluation, except that Murano provides data about Murano environments. Thus user can use any data (e.g., datasource tables, policy rules) available in Congress to define when environment can be deployed.

Table predeploy_error(env_id, obj_id, message) reports list of found errors:

  • env_id environment id where error was detected
  • obj_id object id (in environment id) on which error was detected
  • message text message of error

Murano environment serialization/decomposition is described in Congress Support in Murano and Murano Congress Driver

Example (generic):

predeploy_error(env_id, obj_id, message) :-
    my-rule-table1(env_id, obj_id),
    concat("", "some error message 1", message)

predeploy_error(env_id, obj_id, message) :-
    my-rule-table2(env_id, obj_id),
    concat("", "some error message 2", message)

my-rule-table1(env_id, obj_id) :- ....

my-rule-table2(env_id, obj_id) :- ....

Example (allow only environments where all VM instances has flavor with max 2048MB RAM):

predeploy_error(eid, oid, msg) :-
    murano:object(oid, eid, type),
    concat("", "Instance flavor has RAM size over 2048MB", msg)

checkIfError(oid) :-
    murano:parent_type(oid, "io.murano.resources.Instance"),
    murano:property(oid, "flavor", fname),

Enforcement point will use Congress simulation api to evaluate rules on passed mapped environment into Congress schema.

Proposed change

When user executes deploy action on an environment following steps will be done

  • environment will be mapped into update sequence
  • Congress simulation API will be executed:
openstack congress  policy simulate murano_system 'predeploy-error(envId, objId, message)'  'env+(1000,"myEnv") obj+(1,1000,"VM") prop+(100,1,"name", "vm1")  prop+(101,1,"image", "ubuntulinuximg") obj+(2,1000,"Tomcat") prop+(110,2,"name", "tomcat") prop+(111,2,"port", 8080) rel+(200,2,1, "instance") '  action
  • if response will contain non empty result, then deployment will fails



Data model impact


REST API impact


Versioning impact


Other end user impact

Environment deployment may fail due to policy validation failure.

Deployer impact

Policy enforcement will be used only if

  • Enforcement is enabled in murano.conf
  • Congress is available in Keystone catalog (i.e., it is deployed in OpenStack)

Developer impact


Murano-dashboard / Horizon impact




Primary assignee:
Other contributors:
filip-blaha, radek-pospisil

Work Items

  1. Use implementation of Congress Support in Murano in order to implement policy enforcement point as advised by Stan (see below). The Congress support must correctly deal with following setups
  • Openstack with Congress installed
  • Openstack without Congress
Stan: such approach makes PolicyEnforces (and thus dependency on Congress) be   mandatory for Murano. Better approach for now could be just insert
at https://github.com/stackforge/murano/blob/master/murano/common/engine.py#L112
something like

if config.CONF.enable_policy_enforcer:
  1. Provide Developer and User Documentation (see Documentation section).


Unit and integration tests must be done.

Integration tests must cover following setups

  • Openstack has Congress installed
    • situations when Congress is running (i.e., responding) and not running (i.e., not responding) must be tested
  • Openstack has not Congress installed

Documentation Impact

Policy enforcement must be documented from following perspectives

  • Setup configuration (e.g., with and without congress)
  • Murano rules (i.e., Murano environment data decompositiion) in Murano policy
  • How Murano policy affects environment deployment

Following Murano documentation will be affected

  • Murano Installation Guide

    Add section on Congress requirement and section on enabling policy enforcement

  • Murano Workflow

    Add section on Murano policy enforcement

  • Murano Article (new)

    Article on Murano policy rules (e.g., Murano environment decomposition to Congress)