Cannot ping the VIP of a container by its service name across multi-host in 1.12 swarm mode #25497
Description
I cannot ping the container on another docker host by its service name if the --endpoint-mode is vip.
To reproduce the problem, I create a 2-node swarm cluster by following commands:
docker-machine create -d virtualbox node-1
docker-machine create -d virtualbox node-2
ManagerIP=`docker-machine ip node-1`
docker-machine ssh node-1 docker swarm init --advertise-addr ${ManagerIP}
WorkerToken=`docker-machine ssh node-1 docker swarm join-token worker | grep token | awk '{ print $2 }'`
docker-machine ssh node-2 "docker swarm join --token ${WorkerToken} ${ManagerIP}:2377 --advertise-addr $(docker-machine ip node-2)"Then, I created an overlay network:
eval "$(docker-machine env node-1)"
docker network create -d overlay frontendThen, I created 4 services
docker service create \
--name s1 \
--constraint 'node.hostname == node-1' \
--network frontend \
nginx:latest
docker service create \
--name s2 \
--constraint 'node.hostname == node-2' \
--network frontend \
nginx:latest
docker service create \
--name s3 \
--constraint 'node.hostname == node-1' \
--network frontend \
--endpoint-mode dnsrr \
nginx:latest
docker service create \
--name s4 \
--constraint 'node.hostname == node-2' \
--network frontend \
--endpoint-mode dnsrr \
nginx:latests1 and s2 are --endpoint-mode=vip by default,
s3 and s4 are specified --endpoint-mode=dnsrr.
As the constraints setting, s1 and s3 will run on node-1, and s2 and s4 will run on node-2.
Then, ping test matrix are:
| s1 | s2 | s3 | s4 | |
|---|---|---|---|---|
| s1 | ok | x | ok | ok |
| s2 | x | ok | ok | ok |
| s3 | ok | x | ok | ok |
| s4 | x | ok | ok | ok |
All vips acrossed multi-host are not pingable.
For the failed pings, it returned the error Destination Host Unreachable, such as,
root@ab79b97007a6:/# ping s1
PING s1 (10.0.0.2): 56 data bytes
92 bytes from ab79b97007a6 (10.0.0.7): Destination Host Unreachable
92 bytes from ab79b97007a6 (10.0.0.7): Destination Host Unreachable
92 bytes from ab79b97007a6 (10.0.0.7): Destination Host Unreachable
^C--- s1 ping statistics ---
4 packets transmitted, 0 packets received, 100% packet lossI tried the command ping tasks.{service-name} mentioned in #24201, it's pingable in all cases.