k8s启动容器实例应用时的问题总结

1.创建一个nginx的deployment，创建成功，查看pod分配的ip信息，在pod所在的node节点上使用ping的通，在master上ping不通：

分析:首先想到的就flanneld在两个节点上没有正常运行

    1.查看flanneld的网卡信息 

[root@k8s2-1 ~]# ifconfig
docker0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1472
        inet 10.25.1.1  netmask 255.255.255.0  broadcast 0.0.0.0
        inet6 fe80::42:c5ff:fe30:de12  prefixlen 64  scopeid 0x20<link>
        ether 02:42:c5:30:de:12  txqueuelen 0  (Ethernet)
        RX packets 58  bytes 3880 (3.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 18  bytes 1412 (1.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
ens33: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.191.21  netmask 255.255.255.0  broadcast 192.168.191.255
        inet6 fe80::370c:bd9e:9b5a:ed83  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:de:b2:e0  txqueuelen 1000  (Ethernet)
        RX packets 34986  bytes 15926405 (15.1 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 33482  bytes 6913324 (6.5 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
flannel0: flags=4305<UP,POINTOPOINT,RUNNING,NOARP,MULTICAST>  mtu 1472
        inet 10.25.1.0  netmask 255.255.0.0  destination 10.25.1.0
        inet6 fe80::1b37:644b:a7ca:c658  prefixlen 64  scopeid 0x20<link>
        unspec 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00  txqueuelen 500  (UNSPEC)
        RX packets 785  bytes 65940 (64.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 19  bytes 1488 (1.4 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 247  bytes 29744 (29.0 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 247  bytes 29744 (29.0 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
veth5112d6a: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1472
        inet6 fe80::54f3:44ff:fed1:43f3  prefixlen 64  scopeid 0x20<link>
        ether 56:f3:44:d1:43:f3  txqueuelen 0  (Ethernet)
        RX packets 18  bytes 1412 (1.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 41  bytes 3290 (3.2 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

    flannel0网卡信息就是安装flanneld组件后，自动创建的。一个tun虚拟网卡，接收不在同一主机的POD的数据，然后将收到的数据转发给flanneld进程

    venth5112a网卡：cni0为在同一主机pod共用的网桥，当kubelet创建容器时，将为此容器创建虚拟网卡vethxxx，并桥接到cni0网桥

    2.查看etcd中保存的网络配置信息，信息正常

[root@k8s1-1 ~]# etcdctl  ls
/k8s
/registry
[root@k8s1-1 ~]# etcdctl  ls  /k8s/network
/k8s/network/subnets
/k8s/network/config
[root@k8s1-1 ~]# etcdctl  ls  /k8s/network/subnets
/k8s/network/subnets/10.25.1.0-24
/k8s/network/subnets/10.25.15.0-24
/k8s/network/subnets/10.25.92.0-24
[root@k8s1-1 ~]# etcdctl  ls  /k8s/network/subnets/10.25.1.0-24
/k8s/network/subnets/10.25.1.0-24
[root@k8s1-1 ~]# etcdctl  get   /k8s/network/subnets/10.25.1.0-24
{"PublicIP":"192.168.191.21"}
[root@k8s1-1 ~]# etcdctl  get   /k8s/network/subnets/10.25.15.0-24
{"PublicIP":"192.168.191.20"}
[root@k8s1-1 ~]# etcdctl  get   /k8s/network/subnets/10.25.15.0-24

    3.查看node节点的路由信息，其中xxx.xxx.1.0  xxx.xxx.1.1网桥信息，在master中都时可以ping通的，具体到pod的ip时就ping不通，很纳闷。

    4.最后想到的就k8s还与iptables有关，执行了iptables -P INPUT ACCEPT;iptables -P FORWARD ACCEPT;iptables -F后再次ping终于成功了。

2.{kubelet k8s-node-2} spec.containers{ct} Warning BackOff Back-off restarting failed docker container

    镜像没有运行进程，当然就直接退出