I have two servers in Docker Swarm, but when I need to add a third server - I get the result:
docker-machine加入節點時出現錯誤：
Error response from daemon: rpc error: code = 14 desc = grpc: the connection is unavailable
All servers in one network.
所有服務處於同意網絡
What could be the problem?
問題是？
From official Docker swarm tutorial
官方文檔，對於swarm之旅：
The following ports must be open on your docker hosts.
docker主機之間下面端口應該打開
**TCP port 2377 for cluster management communications
TCP and UDP port 7946 for communication among nodes
UDP port 4789 for overlay network traffic**
To enable this ports run the below command on all your docker hosts. kindly follow the digitalocen article for complete steps.
可以在所有docker hosts上運行以下命令，請參照完整的digitalocen完整步驟
firewall-cmd --add-port=2376/tcp --permanent
firewall-cmd --add-port=2377/tcp --permanent
firewall-cmd --add-port=7946/tcp --permanent
firewall-cmd --add-port=7946/udp --permanent
firewall-cmd --add-port=4789/udp --permanent