Docker 容器启动：WARNING: IPv4 forwarding is disabled. Networking will not work

第一次启动还正常呢，第二次启动就不可以了。

[root[@xxxxxx](https://my.oschina.net/xxww) ~]#  docker run -d -P training/webapp python app.py
WARNING: IPv4 forwarding is disabled. Networking will not work.
a73aab05adde4xxxxxxxxxxff205ba8a9262bcb6759fda787e30764b6a32963e

解决办法：在宿主机（就是Docker所在的操作系统）上操作

1. 修改 /usr/lib/sysctl.d/00-system.conf 文件，在结尾添加 net.ipv4.ip_forward=1，

    [root[@xxxxxx](https://my.oschina.net/xxww) ~]# vim /usr/lib/sysctl.d/00-system.conf
   
    # Kernel sysctl configuration file
    #
    # For binary values, 0 is disabled, 1 is enabled.  See sysctl(8) and
    # sysctl.conf(5) for more details.
   
    # Disable netfilter on bridges.
    net.bridge.bridge-nf-call-ip6tables = 0
    net.bridge.bridge-nf-call-iptables = 0
    net.bridge.bridge-nf-call-arptables = 0
    net.ipv4.ip_forward=1
   

2. 然后重启 network

    [root[@xxxxxx](https://my.oschina.net/xxww) ~]# systemctl restart network
   

再执行启动容器就可以了

[root[@bogon](https://my.oschina.net/u/3914826) sysctl.d]#  docker run -d -P training/webapp python app.py
5b5783abf0a2xxxxxxxxxx5ec5f79099415ad46e18122aa120852d47958b5eb7

参考文档：Locutus