[BUG] waiting for the master to sign the yurthub certificate

Could you please post the version of yurthub and yurt-controller-manager and the log of yurt-controller-manager?
yurt-controller-manager: lastest
yurthub: : lastest

It seems that images are not latest enough, since we post images to dockerhub every day. It's impossible that the latest images were created 8 months ago.
Also, the tag latest is not the official released version. Please use v0.7.0 and try again.
openyurt/yurthub:v0.7.0
openyurt/yurt-controller-manager:v0.7.0
And I guess the error occurs because of using a newer yurt-controller-manager.yaml in which the authorization of approving kubernetes.io/legacy-unknown has been removed in pr #809.
@beatyman Thank you for raising issue. as @Congrool reply, if you can update your local yurt-app-manager/yurthub image, the problem will be solved.