kubenetes创建pod后，无法启动容器

1、获取pod信息
[root@izwz98e5znt7xgdg8aj0cfz ~]# kubectl get pod

NAME                 READY     STATUS              RESTARTS   AGE
redis-master-c9gzd   0/1       ContainerCreating   0          17m

2、查看pod events
[root@izwz98e5znt7xgdg8aj0cfz ~]# kubectl describe pod redis-master-c9gzd

Name:       redis-master-c9gzd
Namespace:  default
Node:       127.0.0.1/127.0.0.1
Start Time: Sun, 05 Aug 2018 10:35:18 +0800
Labels:     name=redis-master
Status:     Pending
IP:     
Controllers:    ReplicationController/redis-master
Containers:
  master:
    Container ID:       
    Image:          kubeguide/redis-master
    Image ID:           
    Port:           6379/TCP
    State:          Waiting
      Reason:           ContainerCreating
    Ready:          False
    Restart Count:      0
    Volume Mounts:      <none>
    Environment Variables:  <none>
Conditions:
  Type      Status
  Initialized   True 
  Ready     False 
  PodScheduled  True 
No volumes.
QoS Class:  BestEffort
Tolerations:    <none>
Events:
  FirstSeen LastSeen    Count   From            SubObjectPath   Type        Reason      Message
  --------- --------    -----   ----            -------------   --------    ------      -------
  17m       17m     1   {default-scheduler }            Normal      Scheduled   Successfully assigned redis-master-c9gzd to 127.0.0.1
  17m       1m      8   {kubelet 127.0.0.1}         Warning     FailedSync  Error syncing pod, skipping: failed to "StartContainer" for "POD" with ErrImagePull: "image pull failed for registry.access.redhat.com/rhel7/pod-infrastructure:latest, this may be because there are no credentials on this request.  details: (open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory)"

  17m   8s  74  {kubelet 127.0.0.1}     Warning FailedSync  Error syncing pod, skipping: failed to "StartContainer" for "POD" with ImagePullBackOff: "Back-off pulling image \"registry.access.redhat.com/rhel7/pod-infrastructure:latest\""

错误信息为open /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt: no such file or directory，导致docker拉取pause镜像失败

3、查看redhat-ca.crt，发现是一个软连接，且该软连接对应的文件[root@izwz98e5znt7xgdg8aj0cfz ~]# ll /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt

lrwxrwxrwx 1 root root 27 Aug  4 07:12 /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt -> /etc/rhsm/ca/redhat-uep.pem

4、在网上找了该问题的处理方法，安装rhsm相关的库：yum install rhsm
安装完成后，执行一下docker pull registry.access.redhat.com/rhel7/pod-infrastructure:latest

如果依然报错，可参考下面的方法：

wget http://mirror.centos.org/centos/7/os/x86_64/Packages/python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm
rpm2cpio python-rhsm-certificates-1.19.10-1.el7_4.x86_64.rpm | cpio -iv --to-stdout ./etc/rhsm/ca/redhat-uep.pem | tee /etc/rhsm/ca/redhat-uep.pem

该令会生成/etc/rhsm/ca/redhat-uep.pem文件.

5、再次查看/etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt文件
[root@izwz98e5znt7xgdg8aj0cfz Guestbook]# ll /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt

lrwxrwxrwx 1 root root 27 Aug  4 07:12 /etc/docker/certs.d/registry.access.redhat.com/redhat-ca.crt -> /etc/rhsm/ca/redhat-uep.pem

[root@izwz98e5znt7xgdg8aj0cfz Guestbook]# ll /etc/rhsm/ca/redhat-uep.pem

-rw-r--r-- 1 root root 7732 Aug  5 11:00 /etc/rhsm/ca/redhat-uep.pem

发现文件/etc/rhsm/ca/redhat-uep.pem已经生成

6、此时再查看pod，已是running状态
[root@izwz98e5znt7xgdg8aj0cfz Guestbook]# kubectl get pod

NAME                 READY     STATUS    RESTARTS   AGE
redis-master-rbc3k   1/1       Running   0          25s

至此，docker拉取pause镜像失败的问题得到解决