Config Connector includes a collection of Custom Resource Definitions (CRDs). Each CRD allows you to configure a single Google Cloud resource. These resources persist in your cluster as custom Kubernetes resources.
For example, the Config Connector resource type named
to a Pub/Sub Topic resource. Each Config Connector resource is a
This page describes how Config Connector uses those object types.
Additionally, Config Connector allows you to leverage a number of Kubernetes features for managing Google Cloud resources.
Kubernetes Objects and Config Connector resources
Specfield contains all the fields that define an object's desired state, with the exception of
Labels. The subfields of
Specrefer to the associated Google Cloud resource. When you change a subfield, the value of the Google Cloud resource's associated field is eventually consistent with your intended value.
- An example of a writable field is
databaseVersionin a SQLInstance resource.
Statusfield is read-only and contains the current state of your object. Config Connector periodically reads information on your Google Cloud resource and updates the
- An example of a read-only
Statusfield is the
connectionNameof a SQLInstance resource.
Each Config Connector resource includes a standard Kubernetes metadata
field with the fields
labels. This section
describes these fields.
- Creating a Config Connector resource creates a Google Cloud resource with the same name.
- The namespace you create a Config Connector resource in determines the project that contains the Google Cloud resource. For more on namespaces, see Kubernetes Namespaces and Google Cloud Projects.
- Labels in the metadata field of a Config Connector resource are also added to the associated Google Cloud resource.
- In addition, Config Connector adds a system label named
managed-by-cnrmwith a value of
trueto your Google Cloud resources.
Using RBAC for Access Control
Kubernetes Role Based Access Control (RBAC) secures your resources. You can control creation of Google Cloud resources by assigning RBAC permissions. For more information, see Securing access to resources.
Important status changes for Config Connector resources are visible as Kubernetes events. For more information, see Viewing events.
Declarative configuration and eventual consistency
With declarative configuration, you define the desired state of the system. The system then works constantly to remain as close as possible to this state. See Declarative management of Kubernetes objects using configuration files for more information.
You can create and update resources in any order, regardless of dependency relationships. GKE moves your declared configuration towards eventual consistency with the desired state.
For example, if you create a
PubSubSubscription before the corresponding
PubSubTopic, Config Connector waits until the topic is created before
creating the associated subscription.
The duration your Config Connector installation remains inconsistent
depends on the count and types of resources under management. Changes to a
GKE cluster are
typically executed in seconds. However, the time to create associated
Google Cloud resources can vary based upon the type of resource.
For example, a single
PubSubTopic takes seconds to create.
Google Cloud resources that take longer to create will leave take longer
to reach consistency. For example, when creating an
SQLInstance and an
SQLDatabase, the system is inconsistent for a period of minutes while the
database is created.
GKE and Config Connector reconcile each resource with every update or every 10 minutes. When there is an error in reconciling, Config Connector retries every 30 seconds with exponential backoff. You can view any errors in the Events of a given resource.