[release-1.21] k3s --disable-agent flag never starts kube-scheduler in newer k3s versions

[brandond]

Backport to branch release-1.21:

• k3s --disable-agent flag never starts kube-scheduler in newer k3s versions #5118

[ShylajaDevadiga]

Validated on v1.21.11+k3s1
Installed node1 passing --disable-agent

ubuntu@ip-172-31-9-152:~$ kubectl get nodes
No resources found

ubuntu@ip-172-31-9-152:~$ kubectl get pods -A
NAMESPACE     NAME                                      READY   STATUS    RESTARTS   AGE
kube-system   helm-install-traefik-crd-s2qz4            0/1     Pending   0          83s
kube-system   helm-install-traefik-fs26g                0/1     Pending   0          83s
kube-system   metrics-server-ff9dbcb6c-vkf62            0/1     Pending   0          82s
kube-system   local-path-provisioner-84bb864455-24b6c   0/1     Pending   0          82s
kube-system   coredns-574bcc6c46-cltl7                  0/1     Pending   0          82s

Joined agent node

ubuntu@ip-172-31-9-152:~$ kubectl get pods -A
NAMESPACE     NAME                                      READY   STATUS              RESTARTS   AGE
kube-system   helm-install-traefik-crd-s2qz4            0/1     ContainerCreating   0          103s
kube-system   helm-install-traefik-fs26g                0/1     ContainerCreating   0          103s
kube-system   local-path-provisioner-84bb864455-24b6c   0/1     ContainerCreating   0          102s
kube-system   metrics-server-ff9dbcb6c-vkf62            0/1     ContainerCreating   0          102s
kube-system   coredns-574bcc6c46-cltl7                  0/1     ContainerCreating   0          102s

ubuntu@ip-172-31-9-152:~$ kubectl get pods -A
NAMESPACE     NAME                                      READY   STATUS      RESTARTS   AGE
kube-system   local-path-provisioner-84bb864455-24b6c   1/1     Running     0          3m13s
kube-system   coredns-574bcc6c46-cltl7                  1/1     Running     0          3m13s
kube-system   helm-install-traefik-crd-s2qz4            0/1     Completed   0          3m14s
kube-system   metrics-server-ff9dbcb6c-vkf62            1/1     Running     0          3m13s
kube-system   helm-install-traefik-fs26g                0/1     Completed   2          3m14s
kube-system   svclb-traefik-tk89l                       2/2     Running     0          62s
kube-system   traefik-56c4b88c4b-jfhql                  1/1     Running     0          62s

ubuntu@ip-172-31-9-152:~$ kubectl get nodes
NAME               STATUS   ROLES    AGE    VERSION
ip-172-31-12-112   Ready    <none>   110s   v1.21.11+k3s1
ubuntu@ip-172-31-9-152:~$