docker容器无法使用外网问题排查及解决办法

查看服务情况

dockcer info

发现如下预警信息：

WARNING: bridge-nf-call-iptables is disabled
WARNING: bridge-nf-call-ip6tables is disabled

查看 /etc/sysctl.conf配置是否包含：

net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.bridge.bridge-nf-call-arptables = 1
net.ipv4.ip_forward = 1

没有需要添加，添加完执行
sysctl -p
如果报错：

cannot stat /proc/sys/net/bridge/bridge-nf-call-iptables
cannot stat /proc/sys/net/bridge/bridge-nf-call-ip6tables

需要加载模块：

modprobe  br_netfilter

再次执行sysctl -p

到这里如果还不能解决问题

查看iptables -L是否包含docker的相关规则

如果没有执行下面指令：

#filter表规则
iptables -N DOCKER
iptables -N DOCKER-ISOLATION-STAGE-1
iptables -N DOCKER-ISOLATION-STAGE-2
iptables -N DOCKER-USER
iptables -A FORWARD -j DOCKER-USER
iptables -A FORWARD -j DOCKER-ISOLATION-STAGE-1
iptables -A FORWARD -o docker0 -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
iptables -A FORWARD -o docker0 -j DOCKER
iptables -A FORWARD -i docker0 ! -o docker0 -j ACCEPT
iptables -A FORWARD -i docker0 -o docker0 -j ACCEPT
iptables -A DOCKER-ISOLATION-STAGE-1 -i docker0 ! -o docker0 -j DOCKER-ISOLATION-STAGE-2
iptables -A DOCKER-ISOLATION-STAGE-1 -j RETURN
iptables -A DOCKER-ISOLATION-STAGE-2 -o docker0 -j DROP
iptables -A DOCKER-ISOLATION-STAGE-2 -j RETURN
iptables -A DOCKER-USER -j RETURN

#nat表规则
iptables -t nat -N DOCKER
iptables -t nat -A PREROUTING -m addrtype --dst-type LOCAL -j DOCKER
iptables -t nat -A OUTPUT ! -d 127.0.0.0/8 -m addrtype --dst-type LOCAL -j DOCKER
iptables -t nat -A POSTROUTING -s 172.17.0.0/16 ! -o docker0 -j MASQUERADE
iptables -t nat -A DOCKER -i docker0 -j RETURN