kubeadm flannel出现ImagePullBackOff

• 查看具体错误原因

[root@node1 ~]# kubectl describe pod kube-flannel-ds-amd64-s6gpb
Error from server (NotFound): pods "kube-flannel-ds-amd64-s6gpb" not found
[root@node1 ~]#
[root@node1 ~]# kubectl describe pod  kube-flannel-ds-amd64-s6gpb  -n kube-system
Name:         kube-flannel-ds-amd64-s6gpb
Namespace:    kube-system
Priority:     0
Node:         node2/192.168.198.189
Start Time:   Fri, 21 Feb 2020 21:56:34 +0800
Labels:       app=flannel
              controller-revision-hash=67f65bfbc7
              pod-template-generation=1
              tier=node
Annotations:  
Status:       Pending
IP:           192.168.198.189
IPs:
  IP:           192.168.198.189
Controlled By:  DaemonSet/kube-flannel-ds-amd64
Init Containers:
  install-cni:
    Container ID:
    Image:         quay.io/coreos/flannel:v0.11.0-amd64
    Image ID:
    Port:          
    Host Port:     
    Command:
      cp
    Args:
      -f
      /etc/kube-flannel/cni-conf.json
      /etc/cni/net.d/10-flannel.conflist
    State:          Waiting
      Reason:       ImagePullBackOff
    Ready:          False
    Restart Count:  0
    Environment:    
    Mounts:
      /etc/cni/net.d from cni (rw)
      /etc/kube-flannel/ from flannel-cfg (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from flannel-token-z7mqh (ro)
Containers:
  kube-flannel:
    Container ID:
    Image:         quay.io/coreos/flannel:v0.11.0-amd64
    Image ID:
    Port:          
    Host Port:     
    Command:
      /opt/bin/flanneld
    Args:
      --ip-masq
      --kube-subnet-mgr
    State:          Waiting
      Reason:       PodInitializing
    Ready:          False
    Restart Count:  0
    Limits:
      cpu:     100m
      memory:  50Mi
    Requests:
      cpu:     100m
      memory:  50Mi
    Environment:
      POD_NAME:       kube-flannel-ds-amd64-s6gpb (v1:metadata.name)
      POD_NAMESPACE:  kube-system (v1:metadata.namespace)
    Mounts:
      /etc/kube-flannel/ from flannel-cfg (rw)
      /run/flannel from run (rw)
      /var/run/secrets/kubernetes.io/serviceaccount from flannel-token-z7mqh (ro)
Conditions:
  Type              Status
  Initialized       False
  Ready             False
  ContainersReady   False
  PodScheduled      True
Volumes:
  run:
    Type:          HostPath (bare host directory volume)
    Path:          /run/flannel
    HostPathType:
  cni:
    Type:          HostPath (bare host directory volume)
    Path:          /etc/cni/net.d
    HostPathType:
  flannel-cfg:
    Type:      ConfigMap (a volume populated by a ConfigMap)
    Name:      kube-flannel-cfg
    Optional:  false
  flannel-token-z7mqh:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  flannel-token-z7mqh
    Optional:    false
QoS Class:       Burstable
Node-Selectors:  
Tolerations:     :NoSchedule
                 node.kubernetes.io/disk-pressure:NoSchedule
                 node.kubernetes.io/memory-pressure:NoSchedule
                 node.kubernetes.io/network-unavailable:NoSchedule
                 node.kubernetes.io/not-ready:NoExecute
                 node.kubernetes.io/pid-pressure:NoSchedule
                 node.kubernetes.io/unreachable:NoExecute
                 node.kubernetes.io/unschedulable:NoSchedule
Events:
  Type     Reason     Age                From               Message
  ----     ------     ----               ----               -------
  Warning  Failed     9h                 kubelet, node2     Failed to pull image "quay.io/coreos/flannel:v0.11.0-amd64": rpc error: code = Unknown desc = Error response from daemon: Get https://quay.io/v2/: net/http: request canceled (Client.Timeout exceeded while awaiting headers)
  Normal   Pulling    9h (x4 over 9h)    kubelet, node2     Pulling image "quay.io/coreos/flannel:v0.11.0-amd64"
  Warning  Failed     9h (x3 over 9h)    kubelet, node2     Failed to pull image "quay.io/coreos/flannel:v0.11.0-amd64": rpc error: code = Unknown desc = Error response from daemon: Get https://quay.io/v2/: net/http: TLS handshake timeout
  Warning  Failed     9h (x4 over 9h)    kubelet, node2     Error: ErrImagePull
  Normal   BackOff    9h (x6 over 9h)    kubelet, node2     Back-off pulling image "quay.io/coreos/flannel:v0.11.0-amd64"
  Warning  Failed     8h (x185 over 9h)  kubelet, node2     Error: ImagePullBackOff
  Normal   Scheduled  46m                default-scheduler  Successfully assigned kube-system/kube-flannel-ds-amd64-s6gpb to node2

从上面可以看到，是因为拉取镜像失败。可以采取手动拉取镜像的方式：

• 在集群内所有节点上操作：

# 手动拉取flannel的docker镜像
docker pull easzlab/flannel:v0.11.0-amd64
# 修改镜像名称
docker tag easzlab/flannel:v0.11.0-amd64 quay.io/coreos/flannel:v0.11.0-amd64

• 在master节点上安装flannel:

下载flannel资源配置清单
[root@K8S00 ~]# wget  https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
安装flannel
[root@K8S00 ~]# kubectl apply -f kube-flannel.yml 
podsecuritypolicy.policy/psp.flannel.unprivileged configured
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.apps/kube-flannel-ds-amd64 created
daemonset.apps/kube-flannel-ds-arm64 created
daemonset.apps/kube-flannel-ds-arm created
daemonset.apps/kube-flannel-ds-ppc64le created
daemonset.apps/kube-flannel-ds-s390x created