【Docker】Docker Swarm连接出现connect: no route to host情况处理

问题

使用Docker Swarm集群部署在CentOS7上时，当worker主机加入集群的时，发生如下错误：

[[email protected] ~]# docker swarm join --token SWMTKN-1-3b4hjen0t7fvxm7w94958pvgayo9pjewbr1r1mbyjkkkwrqoyr-atbt37va65u1emg05rmgfxyi2 192.168.21.131:2377
Error response from daemon: rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp 192.168.21.131:2377: connect: no route to host"

产生原因

端口没有开放

解决办法

办法1：

关闭Leader主机的防火墙

systemctl stop firewalld

办法2

放行连接端口（如上述2377）

#放行命令
firewall-cmd --zone=public --add-port=2377/tcp --permanent #放行2377端口

#其他命令
firewall-cmd --query-port=2377/tcp  #查询2377端口是否开放
firewall-cmd --reload   #重载防火墙

[[email protected] ~]# firewall-cmd --query-port=2377/tcp
no
[[email protected] ~]# firewall-cmd --zone=public --add-port=2377/tcp --permanent 
success
[[email protected] ~]# firewall-cmd --reload
success
[[email protected] ~]# firewall-cmd --query-port=2377/tcp
yes

然后worker主机就可以加入集群了。

[[email protected] ~]# docker swarm join --token SWMTKN-1-3b4hjen0t7fvxm7w94958pvgayo9pjewbr1r1mbyjkkkwrqoyr-atbt37va65u1emg05rmgfxyi2 192.168.21.131:2377
This node joined a swarm as a worker.