kubectl：与服务器 XXX.XXX.XXXXXX 的连接被拒绝

Question

解决我自己的答案。看来真正的问题是通过 DNS 访问和连接到 accounts.google.com。在我检查我已 ping 后：

$ ping accounts.google.com
PING accounts.google.com (216.58.201.141) 56(84) bytes of data.
64 bytes from mad06s25-in-f13.1e100.net (216.58.201.141): icmp_seq=1 ttl=56 time=21.9 ms
64 bytes from mad06s25-in-f13.1e100.net (216.58.201.141): icmp_seq=2 ttl=56 time=19.0 ms
64 bytes from mad06s25-in-f13.1e100.net (216.58.201.141): icmp_seq=3 ttl=56 time=20.4 ms
^C
--- accounts.google.com ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2002ms
rtt min/avg/max/mdev = 19.070/20.468/21.914/1.173 ms

并在命令执行期间跟踪所有打开的文件：

$ strace -eopenat kubectl version
openat(AT_FDCWD, "/proc/sys/net/core/somaxconn", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/proc/stat", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC) = 3
Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:57:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
openat(AT_FDCWD, "/home/shakaran/.kube/config", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/home/shakaran/.config/gcloud/application_default_credentials.json", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/etc/nsswitch.conf", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 3
openat(AT_FDCWD, "/proc/sys/kernel/hostname", O_RDONLY|O_CLOEXEC) = 4
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 3
The connection to the server 104.155.120.114 was refused - did you specify the right host or port?
+++ exited with 1 +++

我尝试找出已打开的连接：

$ systemd-resolve --status | cat
Global
         DNS Servers: 127.0.1.1
                      8.8.8.8
                      8.8.4.4
          DNSSEC NTA: 10.in-addr.arpa
                      16.172.in-addr.arpa
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa
                      18.172.in-addr.arpa
                      19.172.in-addr.arpa
                      20.172.in-addr.arpa
                      21.172.in-addr.arpa
                      22.172.in-addr.arpa
                      23.172.in-addr.arpa
                      24.172.in-addr.arpa
                      25.172.in-addr.arpa
                      26.172.in-addr.arpa
                      27.172.in-addr.arpa
                      28.172.in-addr.arpa
                      29.172.in-addr.arpa
                      30.172.in-addr.arpa
                      31.172.in-addr.arpa
                      corp
                      d.f.ip6.arpa
                      home
                      internal
                      intranet
                      lan
                      local
                      private
                      test

Link 10 (vboxnet3)
      Current Scopes: LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 9 (vboxnet2)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 8 (vboxnet1)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 7 (vboxnet0)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 6 (docker0)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 5 (tun0)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

Link 3 (wlan0)
      Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: no
         DNS Servers: 8.8.8.8
                      8.8.4.4

Link 2 (eth0)
      Current Scopes: none
       LLMNR setting: yes
MulticastDNS setting: no
      DNSSEC setting: allow-downgrade
    DNSSEC supported: yes

我刚刚发现，在我运行接口禁用之后，我已启用 tun0 的 openvpn（阻止与 accounts.google.com 的连接）：

sudo ifconfig tun0 down

我完全理解：

$ kubectl version
Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:57:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:52:34Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
So sorry for all the noise. But probably it is a good idea add this in FAQ's or so for warning the users about VPNs

所以这个问题主要是被拒绝连接。这个问题可能有用Kubernetes 项目中的 #41975使用 -v=4 进行调试，例如：

$ kubectl version -v=4
Client Version: version.Info{Major:"1", Minor:"5", GitVersion:"v1.5.2", GitCommit:"08e099554f3c31f6e6f07b448ab3ed78d0520507", GitTreeState:"clean", BuildDate:"2017-01-12T04:57:25Z", GoVersion:"go1.7.4", Compiler:"gc", Platform:"linux/amd64"}
I0224 11:32:36.914299   30751 helpers.go:221] Connection error: Get https://XXX.XXX.XXX.XXX/api: Post https://accounts.google.com/o/oauth2/token: dial tcp: lookup accounts.google.com on 127.0.1.1:53: read udp 127.0.0.1:46403->127.0.1.1:53: read: connection refused
F0224 11:32:36.914378   30751 helpers.go:116] The connection to the server XXX.XXX.XXX.XXX was refused - did you specify the right host or port?

Answer 1