I am check the cluster info and find kubernetes dashboard pod is pending:

[root@ops001 data]# kubectl get pods --all-namespaces
NAMESPACE     NAME                                   READY   STATUS                     RESTARTS   AGE
default       my-nginx-756fb87568-rcdsm              0/1     Pending                    0          81d
default       my-nginx-756fb87568-vtf46              0/1     Pending                    0          81d
default       soa-room-service-768cfd68d-5zxgd       0/1     Pending                    0          81d
kube-system   coredns-89764d78c-mbcbz                0/1     Pending                    0          123d
kube-system   kubernetes-dashboard-74d7cc788-8fggl   0/1     Pending                    0          15d
kube-system   kubernetes-dashboard-74d7cc788-mk9c7   0/1     UnexpectedAdmissionError   0          123d

this is lack of resource?this is the detail output:

[root@ops001 ~]#  kubectl describe pod kubernetes-dashboard-74d7cc788-8fggl --namespace kube-system
Name:                 kubernetes-dashboard-74d7cc788-8fggl
Namespace:            kube-system
Priority:             2000000000
Priority Class Name:  system-cluster-critical
Node:                 <none>
Labels:               k8s-app=kubernetes-dashboard
                      pod-template-hash=74d7cc788
Annotations:          scheduler.alpha.kubernetes.io/critical-pod:
                      seccomp.security.alpha.kubernetes.io/pod: docker/default
Status:               Pending
IP:
Controlled By:        ReplicaSet/kubernetes-dashboard-74d7cc788
Containers:
  kubernetes-dashboard:
    Image:      gcr.azk8s.cn/google_containers/kubernetes-dashboard-amd64:v1.10.1
    Port:       8443/TCP
    Host Port:  0/TCP
    Args:
      --auto-generate-certificates
    Limits:
      cpu:     100m
      memory:  300Mi
    Requests:
      cpu:        50m
      memory:     100Mi
    Liveness:     http-get https://:8443/ delay=30s timeout=30s period=10s #success=1 #failure=3
    Environment:  <none>
    Mounts:
      /certs from kubernetes-dashboard-certs (rw)
      /tmp from tmp-volume (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from kubernetes-dashboard-token-pmxpf (ro)
Volumes:
  kubernetes-dashboard-certs:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  kubernetes-dashboard-certs
    Optional:    false
  tmp-volume:
    Type:       EmptyDir (a temporary directory that shares a pod's lifetime)
    Medium:
    SizeLimit:  <unset>
  kubernetes-dashboard-token-pmxpf:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  kubernetes-dashboard-token-pmxpf
    Optional:    false
QoS Class:       Burstable
Node-Selectors:  <none>
Tolerations:     CriticalAddonsOnly
                 node.kubernetes.io/not-ready:NoExecute for 360s
                 node.kubernetes.io/unreachable:NoExecute for 360s
Events:          <none>

this is the node top output:

[root@ops001 ~]# top
top - 23:45:57 up 244 days,  5:56,  7 users,  load average: 3.45, 2.93, 3.77
Tasks: 245 total,   1 running, 244 sleeping,   0 stopped,   0 zombie
%Cpu(s): 38.6 us,  8.4 sy,  0.0 ni, 49.2 id,  3.4 wa,  0.0 hi,  0.4 si,  0.0 st
KiB Mem : 16266412 total,  3963688 free,  5617380 used,  6685344 buff/cache
KiB Swap:        0 total,        0 free,        0 used. 10228760 avail Mem

the kube-scheduler service is up.I have no idea where is going wrong.