Ignore unspecified fields

This page explains the default populating behavior of the spec fields and how to change the default behavior from Merge to the recommended behavior Absent. This page might not be applicable if you're using a CRD added in version 1.114.0 and later because those CRDs use only the Absent behavior. For a list of CRDs that support Merge, see the CRDs with Merge support section of this page.

`spec` fields populating behaviors

When Config Connector creates a resource, fields left unspecified in the Kubernetes resource spec may have two different default populating behaviors: Absent and Merge.

Absent

Absent is the recommended behavior. Config Connector will not populate any unspecified fields into the spec.

For CRDs added in version 1.114.0 and later, the default populating behavior is Absent. This is also the only populating behavior those CRDs support. The value of the cnrm.cloud.google.com/state-into-spec annotation is absent in these resource CRs.

Merge

Merge is an unsupported behavior in CRDs added in 1.114.0 and later. The spec fields take on values from the API after a successful reconciliation unless they are not readable. More details can be found in Manage fields externally.

For CRDs supported in Config Connector version 1.113.0 and earlier, the default populating behavior is Merge. For a list of CRDs that support Merge, see the CRDs with Merge support section of this page. The default value of the cnrm.cloud.google.com/state-into-spec annotation is merge in these resource CRs. You can also configure the populating behavior to be Absent following the instructions in Skip populating unspecified fields into spec.

By default, in these resource CRs, fields which haven't been specified in your original YAML always appear in the CR spec. This means when you run kubectl get <resource kind> <resource name> -oyaml, many fields in the spec are not in your applied YAML.

As an example, assume the CRD schema let you specify two fields named foo and bar in spec, while your applied YAML file has only foo specified:

spec:
  foo: "foo"

You'll notice another field named bar appears in the CR if the YAML is applied successfully and the resource is UpToDate:

spec:
  foo: "foo"
  bar: "bar"

Due to the complexity of interaction between Config Connector and Google Cloud APIs, you might want to change this default behavior and skip populating the Kubernetes resource spec with unspecified fields.

Skip populating unspecified fields into spec

You can skip populating unspecified fields into spec for CRDs supported in Config Connector version 1.113.0 and earlier in either of the following ways:

Configure the cluster-level or namespace-level stateIntoSpec override to be Absent.
Specify the value of the cnrm.cloud.google.com/state-into-spec annotation as absent for the resource.

Configure the cluster-level or namespace-level `stateIntoSpec` override

When installing Config Connector, or updating the Config Connector installation, you can configure the cluster-level or namespace-level stateIntoSpec override to be Absent in the ConfigConnector CR or ConfigConnectorContext CR.

spec:
  stateIntoSpec: Absent

This makes Absent the default spec fields populating behavior for any new resources created in the cluster or in the namespace when you don't specify the cnrm.cloud.google.com/state-into-spec annotation in the new resource YAMLs. It means Config Connector will skip populating unspecified fields into the Kubernetes resource spec for these resources.

The stateIntoSpec field doesn't have a default value. Config Connector will determine the spec fields populating behavior based on the value of the cnrm.cloud.google.com/state-into-spec annotation, and it follows the logic below to determine the value of the annotation:

Use the value of the cnrm.cloud.google.com/state-into-spec annotation directly if it is specified and valid.
If the annotation is unspecified, use the corresponding value of the stateIntoSpec field in the ConfigConnectorContext CR.
If the ConfigConnectorContext CR doesn't exist or the stateIntoSpec field is unspecified, use the corresponding value of the stateIntoSpec field in the ConfigConnector CR.
If the ConfigConnector CR doesn't exist or the stateIntoSpec field is unspecified, use the default behavior based on the CRD described in spec fields populating behaviors.

Note that the only populating behavior CRDs added in version 1.114.0 and later follow is Absent regardless of the cnrm.cloud.google.com/state-into-spec annotation or the stateIntoSpec fields in the ConfigConnector CR or ConfigConnectorContext CR.

If you have already created the resource, but want to change the spec fields populating behavior to Absent, you should:

Ensure the cluster-level or namespace-level stateIntoSpec override to be Absent in the ConfigConnector CR or ConfigConnectorContext CR.
Abandon and acquire the resource. Ensure the YAML configuration used for acquisition does not have the cnrm.cloud.google.com/state-into-spec annotation.

Specify the resource-level `cnrm.cloud.google.com/state-into-spec` annotation

When creating your YAML file, you can specify the value of the cnrm.cloud.google.com/state-into-spec annotation as absent. This skips populating unspecified fields into the Kubernetes resource spec:

metadata:
  annotations:
    cnrm.cloud.google.com/state-into-spec: absent

This annotation has a default value of merge if not specified, which means Config Connector populates all unspecified fields into spec. This annotation is immutable, which means you can't update the annotation value of an existing Config Connector resource.

If you have already created the resource, but want to change the value of this annotation for a different populating behavior, you must follow these steps:

Edit and add annotation cnrm.cloud.google.com/deletion-policy: abandon to the existing Kubernetes resource to make sure deletion in next step won't delete the underlying Google Cloud resource.
Delete the resource from the Kubernetes cluster.
Add annotation cnrm.cloud.google.com/state-into-spec: absent into the YAML of the resource.
(Optional) remove cnrm.cloud.google.com/deletion-policy: abandon from the YAML.
Apply the updated YAML.

To further explain the difference introduced by this annotation, assume there is a spec with the following schema:

foo1: string
foo2: string
bars:
- bar:
    br1: string
    br2: string
barz:
  bz1: string
  bz2: string

Also assume you have specified the spec in your YAML as:

spec:
  foo1: "foo1"
  bars:
  - br1: "1_br1"
  - br1: "2_br1"
  barz:
    bz1: "bz1"

Then by default, the populated spec in the created Kubernetes resource might be:

spec:
  foo1: "foo1"
  foo2: "foo2"
  bars:
  - br1: "1_br1"
    br2: "1_br2"
  - br1: "2_br1"
    br2: "2_br2"
  barz:
    bz1: "bz1"
    bz2: "bz2"

While if you set cnrm.cloud.google.com/state-into-spec: absent, the final spec in the created Kubernetes resource will be:

spec:
  foo1: "foo1"
  bars:
  - br1: "1_br1"
  - br1: "2_br1"
  barz:
    bz1: "bz1"

When to use `cnrm.cloud.google.com/state-into-spec: absent`

In most cases, you'll want to set cnrm.cloud.google.com/state-into-spec: absent to get the Absent populating behavior for spec fields. Here are the most common scenarios that will benefit from the Absent populating behavior.

Manage unspecified fields in a list externally

Config Connector treats all list fields in Kubernetes resource spec as atomic fields. As a result, by default, your change made to a subfield in the list from outside of Config Connector will be reverted by Config Connector. However, you can use this annotation to let Config Connector unmanage subfields in list. For more information, see Behavior for list fields in resource spec.

Resolve fighting between config management tools and Config Connector

If you are using config management tools like Config Sync or Argo CD, you may notice a fight between the config management tool and Config Connector. An example is the KNV2005 error explained in troubleshooting guide. The root cause of these types of issues are because:

Config Connector will populate and default unspecified values in list in the spec, the spec.bars[0].br2 is an example.
Both config management tools and Config Connector treat list fields as atomic, thus the added spec.bars[0].br2 is treated as a drift by config management tools and will be removed to correct the drift.

To resolve these issues, you can set cnrm.cloud.google.com/state-into-spec: absent so that Config Connector doesn't add unspecified field spec.bars[0].br2 into the spec.

Resolve GET/PUT symmetry issues

GET/PUT symmetry refers to a design principle in REST API. Specifically, it means when a GET response is sent as a PUT request to the same URL, the expected result is a HTTP 200 OK response with no change in the state of the underlying REST resource.

The unspecified fields populated by Config Connector in the Kubernetes resource spec are as a result of a GET request. This means in future reconciliations, Config Connector may send a PUT/PATCH request to the underlying Google Cloud API, with these unspecified field values learned from the GET request. This is usually not a problem, but it is possible some Google Cloud APIs will reject the PUT/PATCH request because of these unspecified field values. In the same example, the populated spec.barz.bz2 with value "bz2" may result an HTTP 400 client error or other unexpected responses if the API implementation violates the GET/PUT symmetry principle.

To avoid this category of issues, you can experiment setting cnrm.cloud.google.com/state-into-spec: absent and check if the errors during reconciliation will go away.

Observed State

If you need to set cnrm.cloud.google.com/state-into-spec: absent, but your solution depends on the populated values from unspecified fields, check if these fields exist under status.observedState in the CRD schema. If they're represented under status.observedState, then you can set cnrm.cloud.google.com/state-into-spec: absent and still access the values of the unspecified fields after a successful reconciliation.

The status.observedState field contains the live state of the selected, observed fields of the resource that Config Connector observed in the last successful reconciliation. The observed fields are selected if they are dependencies of common use cases, and are computed spec fields. You can find the observed fields in the CRD schemas.

If you can't find the observed fields you want, check for an existing issue or open a new issue in the public issue trackers .

Kinds with `Merge` support

The following are all the Config Connector kinds that support Merge populating behavior:

AccessContextManagerAccessLevel
AccessContextManagerAccessPolicy
AccessContextManagerServicePerimeter
AlloyDBBackup
AlloyDBCluster
AlloyDBUser
ApigeeEnvironment
ApigeeOrganization
ArtifactRegistryRepository
BigQueryDataset
BigQueryJob
BigQueryTable
BigtableAppProfile
BigtableGCPolicy
BigtableInstance
BigtableTable
BillingBudgetsBudget
BinaryAuthorizationAttestor
BinaryAuthorizationPolicy
CertificateManagerCertificate
CertificateManagerCertificateMap
CertificateManagerCertificateMapEntry
CloudBuildTrigger
CloudFunctionsFunction
CloudIdentityGroup
CloudIdentityMembership
CloudSchedulerJob
ComputeAddress
ComputeBackendBucket
ComputeBackendService
ComputeDisk
ComputeExternalVPNGateway
ComputeFirewall
ComputeFirewallPolicy
ComputeFirewallPolicyAssociation
ComputeForwardingRule
ComputeHTTPHealthCheck
ComputeHTTPSHealthCheck
ComputeHealthCheck
ComputeImage
ComputeInstance
ComputeInstanceGroup
ComputeInstanceGroupManager
ComputeInstanceTemplate
ComputeInterconnectAttachment
ComputeNetwork
ComputeNetworkEndpointGroup
ComputeNetworkFirewallPolicy
ComputeNetworkPeering
ComputeNodeGroup
ComputeNodeTemplate
ComputePacketMirroring
ComputeProjectMetadata
ComputeRegionNetworkEndpointGroup
ComputeReservation
ComputeResourcePolicy
ComputeRoute
ComputeRouter
ComputeRouterInterface
ComputeRouterNAT
ComputeRouterPeer
ComputeSSLCertificate
ComputeSSLPolicy
ComputeSecurityPolicy
ComputeServiceAttachment
ComputeSharedVPCHostProject
ComputeSharedVPCServiceProject
ComputeSnapshot
ComputeSubnetwork
ComputeTargetGRPCProxy
ComputeTargetHTTPProxy
ComputeTargetHTTPSProxy
ComputeTargetInstance
ComputeTargetPool
ComputeTargetSSLProxy
ComputeTargetTCPProxy
ComputeTargetVPNGateway
ComputeURLMap
ComputeVPNGateway
ComputeVPNTunnel
ConfigControllerInstance
ContainerAnalysisNote
ContainerAttachedCluster
ContainerCluster
ContainerNodePool
DLPDeidentifyTemplate
DLPInspectTemplate
DLPJobTrigger
DLPStoredInfoType
DNSManagedZone
DNSPolicy
DNSRecordSet
DataFusionInstance
DataflowFlexTemplateJob
DataflowJob
DataprocAutoscalingPolicy
DataprocCluster
DataprocWorkflowTemplate
EdgeContainerCluster
EdgeContainerNodePool
EdgeContainerVpnConnection
EdgeNetworkNetwork
EdgeNetworkSubnet
EventarcTrigger
FilestoreBackup
FilestoreInstance
FirestoreIndex
Folder
GKEHubFeature
GKEHubMembership
IAMAccessBoundaryPolicy
IAMAuditConfig
IAMCustomRole
IAMPartialPolicy
IAMPolicy
IAMPolicyMember
IAMServiceAccount
IAMServiceAccountKey
IAMWorkforcePool
IAMWorkforcePoolProvider
IAMWorkloadIdentityPool
IAMWorkloadIdentityPoolProvider
IAPBrand
IAPIdentityAwareProxyClient
IdentityPlatformConfig
IdentityPlatformOAuthIDPConfig
IdentityPlatformTenant
IdentityPlatformTenantOAuthIDPConfig
KMSCryptoKey
KMSKeyRing
LoggingLogBucket
LoggingLogExclusion
LoggingLogSink
LoggingLogView
MemcacheInstance
MonitoringAlertPolicy
MonitoringGroup
MonitoringMetricDescriptor
MonitoringMonitoredProject
MonitoringNotificationChannel
MonitoringService
MonitoringServiceLevelObjective
MonitoringUptimeCheckConfig
NetworkConnectivityHub
NetworkConnectivitySpoke
NetworkSecurityAuthorizationPolicy
NetworkSecurityClientTLSPolicy
NetworkSecurityServerTLSPolicy
NetworkServicesEndpointPolicy
NetworkServicesGRPCRoute
NetworkServicesGateway
NetworkServicesHTTPRoute
NetworkServicesMesh
NetworkServicesTCPRoute
NetworkServicesTLSRoute
OSConfigGuestPolicy
OSConfigOSPolicyAssignment
PrivateCACAPool
PrivateCACertificate
PrivateCACertificateAuthority
PrivateCACertificateTemplate
Project
PubSubLiteReservation
PubSubSchema
PubSubSubscription
PubSubTopic
RecaptchaEnterpriseKey
RedisInstance
ResourceManagerLien
ResourceManagerPolicy
RunJob
RunService
SQLDatabase
SQLSSLCert
SQLUser
SecretManagerSecret
SecretManagerSecretVersion
Service
ServiceDirectoryEndpoint
ServiceDirectoryNamespace
ServiceDirectoryService
ServiceIdentity
ServiceNetworkingConnection
SourceRepoRepository
SpannerDatabase
SpannerInstance
StorageBucket
StorageBucketAccessControl
StorageDefaultObjectAccessControl
StorageNotification
StorageTransferJob
VPCAccessConnector

The following kinds don't support the Merge populating behavior starting from the corresponding version:

Kind Name	Version
LoggingLogMetric	1.118.1