docker swarm - etcd cluster is unavailable or misconfigured

Question

I'm trying to get started with docker swarm using etcd for the discovery backend . My etcd server is at etcd.programster.org (10.1.0.44) whilst my docker node is at swarm1.programster.org (10.1.0.47). All machines are running on Virtualbox instances on my local network (10.1.0.x).

I manage to get my etcd server running with the following:

MY_IP="10.1.0.44"

./etcd \
-name infra0 \
-initial-advertise-peer-urls http://$MY_IP:2380 \
-listen-peer-urls="http://0.0.0.0:2380,http://0.0.0.0:7001" \
-listen-client-urls="http://0.0.0.0:2379,http://0.0.0.0:4001" \
-advertise-client-urls="http://$MY_IP:2379" \
-initial-cluster-token etcd-cluster-1 \
-initial-cluster infra0=http://$MY_IP:2380 \
-initial-cluster-state new

I can set and retrieve key values from swarm1.programster.org just fine with curl and etcd.

# setting key with etcdctl
./etcdctl --peers http://etcd.programster.org:4001 set etc://etcd.programster.org/mykey "test"

# setting key with curl
curl -L \
http://etcd.programster.org:4001/v2/keys/mykey \
-XPUT -d value="test"

# retrieving key with etcdctl
./etcdctl --peers http://etcd.programster.org:4001 get etc://etcd.programster.org/mykey

# retrieving key with curl
curl -L http://etcd.programster.org:4001/v2/keys/mykey

However, whenever I run a swarm based command such as:

docker run swarm list etcd://10.1.0.44/

or

docker run swarm join --advertise=10.1.0.47:2375 etcd://10.1.0.44/

I always get the following error message:

[timestamp] client: etcd cluster is unavailable or misconfigured

Have I configured my etcd server incorrectly or perhaps there is a networking configuration that I need to perform on the docker node first? I have not performed any TLS authentication yet for simplicity but perhaps swarm will not work without this?

Context

• All machines are running Debian 8 (3.16.0-4-amd64). Also tested with Ubuntu 14.04 for swarm1.programster.org.
• Docker version 1.9.1, build a34a1d5
• etcd version 2.2.2

Answer 1

Try including the port number like this:

docker run swarm join --advertise=10.1.0.47:2375 etcd://10.1.0.44:2379/swarm

I had the same issue and I assumed docker would intelligently infer the port number from "etcd://" - I was wrong.