how to create docker overlay network between multi hosts?

Question

I have been trying to create an overlay network between two hosts with no success. I keep getting the error message:

mavungu@mavungu-Aspire-5250:~$ sudo docker -H tcp://192.168.0.18:2380 network create -d overlay myapp
Error response from daemon: 500 Internal Server Error: failed to parse pool request for address space "GlobalDefault" pool "" subpool "": cannot find address space GlobalDefault (most likely the backing datastore is not configured)

mavungu@mavungu-Aspire-5250:~$ sudo docker network create -d overlay myapp
[sudo] password for mavungu:
Error response from daemon: failed to parse pool request for address space "GlobalDefault" pool "" subpool "": cannot find address space GlobalDefault (most likely the backing datastore is not configured)

My environment details:

mavungu@mavungu-Aspire-5250:~$ sudo docker info Containers: 1
Images: 364 Server Version: 1.9.1 Storage Driver: aufs Root Dir:
/var/lib/docker/aufs Backing Filesystem: extfs Dirs: 368 Dirperm1
Supported: true Execution Driver: native-0.2 Logging Driver:
json-file Kernel Version: 3.19.0-26-generic Operating System: Ubuntu
15.04 CPUs: 2 Total Memory: 3.593 GiB Name: mavungu-Aspire-5250 Registry: https://index.docker.io/v1/ WARNING: No swap limit support

I have a swarm cluster working well with consul as the discovery mechanism:

mavungu@mavungu-Aspire-5250:~$ sudo docker -H tcp://192.168.0.18:2380 info 

Containers: 4 
Images: 51 
Role: primary
Strategy: spread
Filters: health, port, dependency, affinity, constraint
Nodes: 2
mavungu-Aspire-5250: 192.168.0.36:2375
└ Containers: 1
└ Reserved CPUs: 0 / 2
└ Reserved Memory: 0 B / 3.773 GiB
└ Labels: executiondriver=native-0.2, kernelversion=3.19.0-26-generic, operatingsystem=Ubuntu 15.04, storagedriver=aufs
mavungu-HP-Pavilion-15-Notebook-PC: 192.168.0.18:2375
└ Containers: 3
└ Reserved CPUs: 0 / 4
└ Reserved Memory: 0 B / 3.942 GiB
└ Labels: executiondriver=native-0.2, kernelversion=4.2.0-19-generic, operatingsystem=Ubuntu 15.10, storagedriver=aufs
CPUs: 6
Total Memory: 7.715 GiB
Name: bb47f4e57436

My consul is available at 192.168.0.18:8500 and it works well with the swarm cluster.

I would like to be able to create an overlay network across the two hosts. I have configured the docker engines on both hosts with this additional settings:

DOCKER_OPTS="-D --cluster-store-consul://192.168.0.18:8500 --cluster-advertise=192.168.0.18:0"

DOCKER_OPTS="-D --cluster-store-consul://192.168.0.18:8500 --cluster-advertise=192.168.0.36:0"

I had to stop and restart the engines and reset the swarm cluster... After failing to create the overlay network, I changed the --cluster-advertise setting to this :

DOCKER_OPTS="-D --cluster-store-consul://192.168.0.18:8500 --cluster-advertise=192.168.0.18:2375"

DOCKER_OPTS="-D --cluster-store-consul://192.168.0.18:8500 --cluster-advertise=192.168.0.36:2375"

But still it did not work. I am not sure of what ip:port should be set for the --cluster-advertise= . Docs, discussions and tutorials are not clear on this advertise thing.

There is something that I am getting wrong here. Please help.

Answer 1

For anyone coming to this since Docker 1.12 was released, this is now trivially easy - Swarm Mode is built into the engine and you don't need Consul or any other extra components.

Assuming you have two hosts with Docker installed, intitialize the Swarm on the first machine:

> docker swarm init
Swarm initialized: current node (6ujd4o5fx1dmav5uvv4khrp33) is now a manager

To add a worker to this swarm, run the following command:                                                                                                   
docker swarm join \                                                                                                                                     
--token SWMTKN-1-54xs4bn7qs6su3xjjn7ul5am9z9073by2aqpey56tnccbi93zy-blugim00fuozg6qs289etc \                                                         
172.17.0.54:2377

That host becomes the first manager node in the swarm, and it writes out the command you use to join other nodes to the swarm - the secret token, and the IP address where the manager is listening.

On the second host:

> docker swarm join 172.17.0.54:2377 --token SWMTKN-1-54xs4bn7qs6su3xjjn7ul5am9z9073by2aqpey56tnccbi93zy-blugim00fuozg6qs289etc
This node joined a swarm as a worker.

Now you have a secure 2-node swarm which has service discovery, rolling updates and service scaling.

Create your overlay network on the manager node with:

> docker network create -d overlay my-net
d99lmsfzhcb16pdp2k7o9sehv

And you now have a multi-host overlay network with built-in DNS, so services can resolve each other based on service name.