Switching Cluster Perspective in Karmadactl

Karmadactl introduces the flag operation-scope to specify the operation scope of Karmadactl commands. The value of the flag operation-scope is of enum type, with each enum value and its meaning as follows:

• karmada: the operation scope of karmadactl is Karmada control plane.
• members: the operation scope of karmadactl is member clusters.
• all: the operation scope of karmadactl includes Karmada control plane and member clusters.

Note that the operation-scope enumeration values supported by different commands are different, please refer to karmadactl [command] --help for details.

The introduction of operation-scope provides a flexible way to implement Karmadactl cluster perspective switching. Compared to Kubectl, Karmadactl can manage different target clusters without switching contexts. In addition, with Karmada's multi-cluster resource view, Karmadactl can access resource information of multiple target clusters at the same time, which greatly simplifies the daily operation and maintenance in multi-cluster scenarios.

How to Use

This section describes the application of the flag operation-scope to the various Karmadactl commands and uses karmadactl get as an example of how to see the distribution of resources across different clusters by switching cluster perspectives.

get

The command karmadactl get can be used to view the resources of a control plane or member cluster. In combination with the flag operation-scope and clusters, karmadactl get can display information about the resources of a cluster or clusters.

• operation-scope：The enumeration values karmada, members, and all are supported. Defaults to karmada.
• clusters：Used to specify target member clusters and only takes effect when the command's operation scope is members or all.

Assume that the Karmada control plane manages three member clusters, member1, member2, and member3 and that the Karmada control plane's Deployment resource, nginx, is distributed to all three of these member clusters. Then, we can:

• View the distribution of resources across the control plane and all member clusters.

  $ karmadactl get deployment nginx --operation-scope all      
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE   ADOPTION
  nginx   Karmada   0/2     6            0           18h   -
  nginx   member1   0/2     2            0           37s   Y
  nginx   member2   0/2     2            0           36s   Y
  nginx   member3   0/2     2            0           37s   Y

  The CLUSTER column represents the cluster in which the resource resides, and the ADOPTION column represents whether the resource has been taken over by the Karmada control plane.

• View the distribution of resources across the control plane and some of the member clusters.

  $ karmadactl get deployment nginx --operation-scope all --clusters member1,member2
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE     ADOPTION
  nginx   Karmada   4/2     6            4           18h     -
  nginx   member1   2/2     2            2           2m37s   Y
  nginx   member2   0/2     2            0           2m36s   Y

  When --clusters member1,member2 is set, the member cluster perspective of the command will be limited to clusters member1 and member2.

• View the resource of Karmada control plane.

  $ karmadactl get deployment nginx 
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE   ADOPTION
  nginx   Karmada   6/2     6            6           18h   -
  $ karmadactl get deployment nginx --operation-scope karmada 
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE   ADOPTION
  nginx   Karmada   6/2     6            6           18h   -

• View the distribution of resources across all member clusters.

  $ karmadactl get deployment nginx --operation-scope members
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE     ADOPTION
  nginx   member2   2/2     2            2           8m10s   Y
  nginx   member1   2/2     2            2           8m11s   Y
  nginx   member3   2/2     2            2           8m10s   Y

• View the distribution of resources across some of the member clusters.

  $ karmadactl get deployment nginx --operation-scope members --clusters member1,member2
  NAME    CLUSTER   READY   UP-TO-DATE   AVAILABLE   AGE    ADOPTION
  nginx   member1   2/2     2            2           9m7s   Y
  nginx   member2   2/2     2            2           9m6s   Y

describes

In combination with the flag operation-scope and cluster, the karmadactl describe command can be used to display details of resources in Karmada control plane or a member cluster.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.
• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.

attach

In combination with the flag operation-scope and cluster, the karmadactl attach command can attach to a running container in Karmada control plane or a member cluster.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.

• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.

explain

In combination with the flag operation-scope and cluster, the karmadactl explain command can get documentation for a resource in Karmada control plane or a member cluster. This is especially convenient for scenarios where member cluster resources are differentially configured via OverridePolicy.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.
• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.

exec

In combination with the flag operation-scope and cluster, the karmadactl exec command can execute a command in a container in Karmada control plane or a member cluster.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.
• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.

api-resources

In combination with the flag operation-scope and cluster, the karmadactl api-resources command can print the supported API resources on the server in Karmada control plane or a member cluster.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.
• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.

api-versions

In combination with the flag operation-scope and cluster, the karmadactl api-versions command can print the supported API versions on the server in Karmada control plane or a member cluster.

• operation-scope：The enumeration values karmada and members are supported. Default to karmada.
• cluster：Used to specify a target member cluster and only takes effect when the command's operation scope is members.