sysctl -P 报错解决办法
问题症状
修改 linux 内核文件 
#vi /etc/sysctl.conf后执行sysctl  -P 报错
error: "net.bridge.bridge-nf-call-ip6tables" is an unknown key
error: "net.bridge.bridge-nf-call-iptables" is an unknown key
error: "net.bridge.bridge-nf-call-arptables" is an unknown key
 
解决方法如下：
modprobe bridge
lsmod|grep bridge