InstanceExists should return true when node is unmanaged ones

[MartinForReal]

What type of PR is this?

/kind bug

What this PR does / why we need it:

InstanceExists should return true when node is unmanaged nodes. These nodes are created by kwok/virtual kubelet.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?

virtual node will always exists

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[MartinForReal]

/cherrypick release-1.27

[k8s-infra-cherrypick-robot]

@MartinForReal: once the present PR merges, I will cherry-pick it on top of release-1.27 in a new PR and assign it to you.

In response to this:

/cherrypick release-1.27

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[MartinForReal]

/cherrypick release-1.26

[k8s-infra-cherrypick-robot]

@MartinForReal: once the present PR merges, I will cherry-pick it on top of release-1.26 in a new PR and assign it to you.

In response to this:

/cherrypick release-1.26

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[MartinForReal]

/cherrypick release-1.25

[k8s-infra-cherrypick-robot]

@MartinForReal: once the present PR merges, I will cherry-pick it on top of release-1.25 in a new PR and assign it to you.

In response to this:

/cherrypick release-1.25

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[feiskyer]

thanks for the fix!

/lgtm

[fuweid]

LGTM

Thanks

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: fuweid, MartinForReal

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [MartinForReal]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-infra-cherrypick-robot]

@MartinForReal: new pull request created: #4394

In response to this:

/cherrypick release-1.27

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[k8s-infra-cherrypick-robot]

@MartinForReal: new pull request created: #4395

In response to this:

/cherrypick release-1.26

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[k8s-infra-cherrypick-robot]

@MartinForReal: new pull request created: #4396

In response to this:

/cherrypick release-1.25

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.