swarm deamon port VS. swarmkit port

I have two VMs (myvm1 and myvm2) and myvm1 is set as swarm manager.
scaab101:~ uadmin$ docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM DOCKER ERRORS
myvm1 – virtualbox Running tcp://192.168.99.100:2376 v17.06.1-ce
myvm2 – virtualbox Running tcp://192.168.99.101:2376 v17.06.1-ce
scaab101:~ uadmin$ docker-machine ssh myvm1 “docker swarm init –advertise-addr 192.168.99.100:2376”
Swarm initialized: current node (8g5gscgtpvnc4kg4rgqqp4czi) is now a manager.

To add a worker to this swarm, run the following command:

docker swarm join –token SWMTKN-1-24nwzfj1jww1w4b4sle3udr6a99rh7hhyca5w22scmpi8q9oh5-3rzbf69pv3yhe80b1xpfaczeg 192.168.99.100:2376

To add a manager to this swarm, run ‘docker swarm join-token manager’ and follow the instructions.
scaab101:~ uadmin$ docker-machine ssh myvm2 “docker swarm join” \
> –token SWMTKN-1-24nwzfj1jww1w4b4sle3udr6a99rh7hhyca5w22scmpi8q9oh5-3rzbf69pv3yhe80b1xpfaczeg \
scaab101:~ uadmin$ docker-machine ssh myvm2 “docker swarm join \
> –token SWMTKN-1-24nwzfj1jww1w4b4sle3udr6a99rh7hhyca5w22scmpi8q9oh5-3rzbf69pv3yhe80b1xpfaczeg \
> 192.168.99.100:2376”
Error response from daemon: rpc error: code = 13 desc = connection error: desc = “transport: remote error: tls: bad certificate”
exit status 1

(The error here is because I use 2376 to try to join myvm2 to swarm as a worker. 2376 here is swarm daemon port. I should use a different one, say, 2377 to join. 2377 here is a swarmkit port)
scaab101:~ uadmin$ docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM DOCKER ERRORS
myvm1 – virtualbox Running tcp://192.168.99.100:2376 v17.06.1-ce
myvm2 – virtualbox Running tcp://192.168.99.101:2376 v17.06.1-ce
scaab101:~ uadmin$ docker-machine ssh myvm1 “docker swarm leave –force”
Node left the swarm.
scaab101:~ uadmin$ docker-machine ls
NAME ACTIVE DRIVER STATE URL SWARM DOCKER ERRORS
myvm1 – virtualbox Running tcp://192.168.99.100:2376 v17.06.1-ce
myvm2 – virtualbox Running tcp://192.168.99.101:2376 v17.06.1-ce
scaab101:~ uadmin$ docker-machine ssh myvm1 “docker swarm init –advertise-addr 192.168.99.100:2377
Swarm initialized: current node (eq8iugdzo3aez24dhpj3au6hj) is now a manager.

To add a worker to this swarm, run the following command:

docker swarm join –token SWMTKN-1-1np3bem2tuziipajx9hnh8yj10pkovx046b4itinru1uazeq57-6e5noxm3to8lvmwbanqee048r 192.168.99.100:2377

To add a manager to this swarm, run ‘docker swarm join-token manager’ and follow the instructions.

scaab101:~ uadmin$ docker-machine ssh myvm2 “docker swarm join –token SWMTKN-1-1np3bem2tuziipajx9hnh8yj10pkovx046b4itinru1uazeq57-6e5noxm3to8lvmwbanqee048r 192.168.99.100:2377”
This node joined a swarm as a worker.
scaab101:~ uadmin$