IPIP模式下，若MTU值为1400时，webrouter存在网络问题

[cloudfly]

webrouter 到其他节点的 container 请求都会超时。

Send-Q出现阻塞

Proto Recv-Q Send-Q Local Address Foreign Address State 
tcp 0 0 0.0.0.0:8080 0.0.0.0:* LISTEN 
tcp 0 0 127.0.0.11:39252 0.0.0.0:* LISTEN 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37913 CLOSE_WAIT 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37914 CLOSE_WAIT 
tcp 0 3326 172.20.0.66:8080 172.20.0.3:37912 ESTABLISHED 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37908 CLOSE_WAIT 
tcp 0 25041 172.20.0.66:8080 172.20.0.3:38179 LAST_ACK 
tcp 0 25040 172.20.0.66:8080 172.20.0.3:38218 ESTABLISHED 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37867 CLOSE_WAIT 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37858 CLOSE_WAIT 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37907 CLOSE_WAIT 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37868 CLOSE_WAIT 
tcp 1 83212 172.20.0.66:8080 172.20.0.3:37859 CLOSE_WAIT

Drop 了很多网络包

tunl0: flags=193<UP,RUNNING,NOARP> mtu 1440
inet 172.20.0.128 netmask 255.255.255.255
tunnel txqueuelen 0 (IPIP Tunnel)
RX packets 351 bytes 57201 (55.8 KiB)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 283 bytes 35129 (34.3 KiB)
TX errors 0 dropped 329 overruns 0 carrier 0 collisions 0

[cloudfly]

@frostynova 了解是怎么个原理么？

想看看有没有方法绕过去，若不能就得在文档里说明一下了。

[frostynova]

https://github.com/projectcalico/calico-containers/issues/610

和这个相关么

[cloudfly]

恩，看起来应该就是这个问题了。