Stack domain users allow the Orchestration service to authorize and start the following operations within booted virtual machines:
Provide metadata to agents inside instances. Agents poll for changes and apply the configuration that is expressed in the metadata to the instance.
Detect when an action is complete. Typically, software configuration on a virtual machine after it is booted. Compute moves the VM state to “Active” as soon as it creates it, not when the Orchestration service has fully configured it.
Provide application level status or meters from inside the instance. For example, allow auto-scaling actions to be performed in response to some measure of performance or quality of service.
The Orchestration service provides APIs that enable all of these operations, but all of those APIs require authentication. For example, credentials to access the instance that the agent is running upon. The heat-cfntools agents use signed requests, which require an ec2 key pair created through Identity. The key pair is then used to sign requests to the Orchestration CloudFormation and CloudWatch compatible APIs, which are authenticated through signature validation. Signature validation uses the Identity ec2tokens extension.
Stack domain users encapsulate all stack-defined users (users who are created as a result of data that is contained in an Orchestration template) in a separate domain. The separate domain is created specifically to contain data related to the Orchestration stacks only. A user is created, which is the domain admin, and Orchestration uses the domain admin to manage the lifecycle of the users in the stack user domain.
To configure stack domain user, the Orchestration service completes the following tasks:
A special OpenStack Identity service domain is created. For
example, a domain that is called heat
and the ID is set with the
stack_user_domain
option in the heat.conf
file.
A user with sufficient permissions to create and delete projects
and users in the heat
domain is created.
The username and password for the domain admin user is set in the
heat.conf
file (stack_domain_admin
and
stack_domain_admin_password
). This user administers
stack domain users on behalf of stack owners, so they no longer
need to be administrators themselves. The risk of this escalation path
is limited because the heat_domain_admin
is only given
administrative permission for the heat
domain.
To set up stack domain users, complete the following steps:
Create the domain:
$OS_TOKEN
refers to a token. For example, the service admin
token or some other valid token for a user with sufficient roles
to create users and domains. $KS_ENDPOINT_V3
refers to the v3
OpenStack Identity endpoint (for example,
http://keystone_address:5000/v3
where keystone_address is
the IP address or resolvable name for the Identity
service).
$ openstack --os-token $OS_TOKEN --os-url=$KS_ENDPOINT_V3 --os-\
identity-api-version=3 domain create heat --description "Owns \
users and projects created by heat"
The domain ID is returned by this command, and is referred to as
$HEAT_DOMAIN_ID
below.
Create the user:
$ openstack --os-token $OS_TOKEN --os-url=$KS_ENDPOINT_V3 --os-\
identity-api-version=3 user create --password $PASSWORD --domain \
$HEAT_DOMAIN_ID heat_domain_admin --description "Manages users \
and projects created by heat"
The user ID is returned by this command and is referred to as
$DOMAIN_ADMIN_ID
below.
Make the user a domain admin:
$ openstack --os-token $OS_TOKEN --os-url=$KS_ENDPOINT_V3 --os-\
identity-api-version=3 role add --user $DOMAIN_ADMIN_ID --domain \
$HEAT_DOMAIN_ID admin
Then you must add the domain ID, username and password from these
steps to the heat.conf
file:
stack_domain_admin_password = password
stack_domain_admin = heat_domain_admin
stack_user_domain = domain id returned from domain create above
The following steps are run during stack creation:
Orchestration creates a new stack domain project in the heat
domain if the stack contains any resources that require creation
of a stack domain user.
For any resources that require a user, the Orchestration service creates
the user in the stack domain project. The stack domain project is
associated with the Orchestration stack in the Orchestration
database, but is separate and unrelated (from an authentication
perspective) to the stack owners project. The users who are created
in the stack domain are still assigned the heat_stack_user
role, so
the API surface they can access is limited through
the policy.yaml
file.
For more information, see :keystone-doc:`OpenStack Identity documentation
<>`.
When API requests are processed, the Orchestration service performs
an internal lookup, and allows stack details for a given stack to be
retrieved. Details are retrieved from the database for
both the stack owner’s project (the default
API path to the stack) and the stack domain project, subject to the
policy.yaml
restrictions.
This means there are now two paths that can result in the same data being retrieved through the Orchestration API. The following example is for resource-metadata:
GET v1/{stack_owner_project_id}/stacks/{stack_name}/\
{stack_id}/resources/{resource_name}/metadata
or:
GET v1/{stack_domain_project_id}/stacks/{stack_name}/\
{stack_id}/resources/{resource_name}/metadata
The stack owner uses the former (via openstack stack resource metadata
STACK RESOURCE
), and any agents in the instance
use the latter.
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