kube-scheduler and kube-controller-manager restarting - kubernetes

Question

I have kubernetes 1.15.3 setup
My kube-controller & kube-scheduler are restarting very frequently . This is happening after kubernetes is upgraded to 1.15.3.
kubectl get po -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-5c98db65d4-nmt5d 1/1 Running 37 24d
coredns-5c98db65d4-tg4kx 1/1 Running 37 24d
etcd-ana01 1/1 Running 1 24d
kube-apiserver-ana01 1/1 Running 10 24d
**kube-controller-manager-ana01 1/1 Running 477 9d**
kube-flannel-ds-amd64-2srzb 1/1 Running 0 12d
kube-proxy-2hvcl 1/1 Running 0 23d
**kube-scheduler-ana01 1/1 Running 518 9d**
tiller-deploy-8557598fbc-kxntc 1/1 Running 0 11d
Here is the logs of the system
Type Reason Age From Message
---- ------ ---- ---- -------
Warning Unhealthy 39m (x500 over 23d) kubelet, ana01 Liveness probe failed: Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
Warning BackOff 39m (x1873 over 23d) kubelet, ana01 Back-off restarting failed container
Normal Pulled 28m (x519 over 24d) kubelet, ana01 Container image "k8s.gcr.io/kube-scheduler:v1.15.3" already present on machine
Normal Created 28m (x519 over 24d) kubelet, ana01 Created container kube-scheduler
Normal Started 27m (x519 over 24d) kubelet, ana01 Started container kube-scheduler
logs are
I0928 09:10:23.554335 1 serving.go:319] Generated self-signed cert in-memory
W0928 09:10:25.002268 1 authentication.go:387] failed to read in-cluster kubeconfig for delegated authentication: open /var/run/secrets/kubernetes.io/serviceaccount/token: no such file or directory
W0928 09:10:25.002523 1 authentication.go:249] No authentication-kubeconfig provided in order to lookup client-ca-file in configmap/extension-apiserver-authentication in kube-system, so client certificate authentication won't work.
W0928 09:10:25.002607 1 authentication.go:252] No authentication-kubeconfig provided in order to lookup requestheader-client-ca-file in configmap/extension-apiserver-authentication in kube-system, so request-header client certificate authentication won't work.
W0928 09:10:25.002947 1 authorization.go:177] **failed to read in-cluster kubeconfig for delegated authorization: open /var/run/secrets/kubernetes.io/serviceaccount/token: no such file or directory**
W0928 09:10:25.003116 1 authorization.go:146] No authorization-kubeconfig provided, so SubjectAccessReview of authorization tokens won't work.
I0928 09:10:25.021201 1 server.go:142] Version: v1.15.3