After installing flannel, docker, and kubernetes on Alibaba Cloud ECS, run docker run -it bash on multiple nodes, and then ping each other's IPs. It is found that the network between the docker containers is not connected, and the iptables configuration of the host is wrong. The original FORWARD chain is configured to DROP by default
iptables -L -n
Chain FORWARD (policy DROP)
Update the FORWARD chain toACCEPT
iptables --policy FORWARD ACCEPT