dashboard: Couldn't read CA certificate: open : no such file or directory

Environment

I installed a single-node kubernetes cluster on CentOS7 using kubeadm according to this manual, then installed the kubernetes-dashboard extension.

Dashboard version:  1.7.1
Kubernetes version: 1.7.5
Operating system: CentOS 7
Node.js version:
Go version: 1.8.3

Observed result

[root@ay pki]# kubectl get pods -n kube-system
NAME                                    READY     STATUS             RESTARTS   AGE
etcd-ay                                 1/1       Running            0          12d
kube-apiserver-ay                       1/1       Running            0          12d
kube-controller-manager-ay              1/1       Running            0          12d
kube-dns-209315428-666w5                3/3       Running            0          12d
kube-proxy-92ss6                        1/1       Running            0          12d
kube-scheduler-ay                       1/1       Running            0          12d
kubernetes-dashboard-1092119393-n9ww6   0/1       CrashLoopBackOff   185        15h
weave-net-wtf68                         2/2       Running            22         1d

[root@ay run]# kubectl logs kubernetes-dashboard-1092119393-n9ww6 -n kube-system
2017/10/25 00:57:16 Using in-cluster config to connect to apiserver
2017/10/25 00:57:16 Starting overwatch
2017/10/25 00:57:16 Using service account token for csrf signing
2017/10/25 00:57:16 No request provided. Skipping authorization
2017/10/25 00:57:16 Successful initial request to the apiserver, version: v1.7.5
2017/10/25 00:57:16 New synchronizer has been registered: kubernetes-dashboard-key-holder-kube-system. Starting
2017/10/25 00:57:16 Starting secret synchronizer for kubernetes-dashboard-key-holder in namespace kube-system
2017/10/25 00:57:16 Initializing secret synchronizer synchronously using secret kubernetes-dashboard-key-holder from namespace kube-system
2017/10/25 00:57:16 Initializing JWE encryption key from synchronized object
2017/10/25 00:57:16 Creating in-cluster Heapster client
2017/10/25 00:57:16 Metric client health check failed: the server could not find the requested resource (get services heapster). Retrying in 30 seconds.
2017/10/25 00:57:16 Serving securely on HTTPS port: 8443
2017/10/25 00:57:16 Couldn't read CA certificate: open : no such file or directory