我有三个节点组成的群:泊坞群缩放行为
$ sudo docker node ls
ID HOSTNAME STATUS AVAILABILITY MANAGER STATUS
i12s3zxsn4vu1c98bv3i5idr8 node03 Ready Active
i2ckxvsju4tmommxim3dbfq7l node02 Ready Active
wak4isl46dn7pbo39drrhphju * node01 Ready Active Leader
然后,我对群运行1个副本Nginx的和他的端口映射到8080:
$ sudo docker service create --replicas 1 --publish 8080:80 --name nginx nginx
$ sudo docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
neahnb9mvi1i nginx replicated 1/1 nginx:latest *:8080->80/tcp
从那里,我可以达到上http://node01:8080
接下来nginx的,我nginx的规模实例6:
$ sudo docker service scale nginx=6
$ sudo docker service ls
ID NAME MODE REPLICAS IMAGE PORTS
neahnb9mvi1i nginx replicated 6/6 nginx:latest *:8080->80/tcp
从那里,我仍然能够达到http://node01:8080 nginx。但是,如果docker swarm将多个节点公开为唯一主机,那么在如此缩放操作期间如何管理端口,因为我所有的nginx服务都映射到同一个8080端口上?在内部由swarm完成的所有服务实例之间是否存在循环负载均衡并在8080上返回答案?