RBAC

4 minute read

Istio RBAC (Role Based Access Control) defines ServiceRole and ServiceRoleBinding objects.

A ServiceRole specification includes a list of rules (permissions). Each rule has the following standard fields:

services: a list of services.
methods: A list of HTTP methods. You can set the value to * to include all HTTP methods. This field should not be set for TCP services. The policy will be ignored. For gRPC services, only POST is allowed; other methods will result in denying services.
paths: HTTP paths or gRPC methods. Note that gRPC methods should be presented in the form of “/packageName.serviceName/methodName” and are case sensitive.

In addition to the standard fields, operators can also use custom keys in the constraints field, the supported keys are listed in the “constraints and properties” page.

Below is an example of ServiceRole object “product-viewer”, which has “read” (“GET” and “HEAD”) access to “products.svc.cluster.local” service at versions “v1” and “v2”. “path” is not specified, so it applies to any path in the service.

apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRole
metadata:
  name: products-viewer
  namespace: default
spec:
  rules:
  - services: ["products.svc.cluster.local"]
    methods: ["GET", "HEAD"]
    constraints:
    - key: "destination.labels[version]"
      values: ["v1", "v2"]

A ServiceRoleBinding specification includes two parts:

The roleRef field that refers to a ServiceRole object in the same namespace.
A list of subjects that are assigned the roles.

In addition to a simple user field, operators can also use custom keys in the properties field, the supported keys are listed in the “constraints and properties” page.

Below is an example of ServiceRoleBinding object “test-binding-products”, which binds two subjects to ServiceRole “product-viewer”:

User “alice@yahoo.com”
Services in “abc” namespace.

apiVersion: "rbac.istio.io/v1alpha1"
kind: ServiceRoleBinding
metadata:
  name: test-binding-products
  namespace: default
spec:
  subjects:
  - user: alice@yahoo.com
  - properties:
      source.namespace: "abc"
  roleRef:
    kind: ServiceRole
    name: "products-viewer"

AccessRule

AccessRule defines a permission to access a list of services.

Field	Type	Description
`services`	`string[]`	Required. A list of service names. Exact match, prefix match, and suffix match are supported for service names. For example, the service name “bookstore.mtv.cluster.local” matches “bookstore.mtv.cluster.local” (exact match), or “bookstore” (prefix match), or “.mtv.cluster.local” (suffix match). If set to [“*”], it refers to all services in the namespace.
`paths`	`string[]`	Optional. A list of HTTP paths or gRPC methods. gRPC methods must be presented as fully-qualified name in the form of “/packageName.serviceName/methodName” and are case sensitive. Exact match, prefix match, and suffix match are supported. For example, the path “/books/review” matches “/books/review” (exact match), or “/books/” (prefix match), or “/review” (suffix match). If not specified, it matches to any path. This field should not be set for TCP services. The policy will be ignored.
`methods`	`string[]`	Optional. A list of HTTP methods (e.g., “GET”, “POST”). If not specified or specified as “*”, it matches to any methods. This field should not be set for TCP services. The policy will be ignored. For gRPC services, only `POST` is allowed; other methods will result in denying services.
`constraints`	`AccessRule.Constraint[]`	Optional. Extra constraints in the ServiceRole specification.

AccessRule.Constraint

Definition of a custom constraint. The supported keys are listed in the “constraint and properties” page.

Field	Type	Description
`key`	`string`	Key of the constraint.
`values`	`string[]`	List of valid values for the constraint. Exact match, prefix match, and suffix match are supported. For example, the value “v1alpha2” matches “v1alpha2” (exact match), or “v1” (prefix match), or “alpha2” (suffix match).

RbacConfig.Mode

Name	Description
`OFF`	Disable Istio RBAC completely, any other config in RbacConfig will be ignored and Istio RBAC policies will not be enforced.
`ON`	Enable Istio RBAC for all services and namespaces.
`ON_WITH_INCLUSION`	Enable Istio RBAC only for services and namespaces specified in the inclusion field. Any other services and namespaces not in the inclusion field will not be enforced by Istio RBAC policies.
`ON_WITH_EXCLUSION`	Enable Istio RBAC for all services and namespaces except those specified in the exclusion field. Any other services and namespaces not in the exclusion field will be enforced by Istio RBAC policies.

RbacConfig.Target

Target defines a list of services or namespaces.

Field	Type	Description
`services`	`string[]`	A list of services.
`namespaces`	`string[]`	A list of namespaces.

RoleRef

RoleRef refers to a role object.

Field	Type	Description
`kind`	`string`	Required. The type of the role being referenced. Currently, “ServiceRole” is the only supported value for “kind”.
`name`	`string`	Required. The name of the ServiceRole object being referenced. The ServiceRole object must be in the same namespace as the ServiceRoleBinding object.

ServiceRole

ServiceRole specification contains a list of access rules (permissions).

Field	Type	Description
`rules`	`AccessRule[]`	Required. The set of access rules (permissions) that the role has.

ServiceRoleBinding

ServiceRoleBinding assigns a ServiceRole to a list of subjects.

Field	Type	Description
`subjects`	`Subject[]`	Required. List of subjects that are assigned the ServiceRole object.
`roleRef`	`RoleRef`	Required. Reference to the ServiceRole object.

Subject

Subject defines an identity. The identity is either a user or identified by a set of properties. The supported keys in properties are listed in “constraint and properties” page.

Field	Type	Description
`user`	`string`	Optional. The user name/ID that the subject represents.
`properties`	`map<string, string>`	Optional. The set of properties that identify the subject.