Overlay Multi-Host Networking

• Just choose --driver overlay when creating network
• For container-to-container traffic inside a single Swarm
• Optional IPSec (AES) encryption on network creation
• Each service can be connected to multiple networks
  • (e.g. front-end, back-end)

Example usage

• Create a new overlay network

[node1] ~> docker network create --driver overlay
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[node1] ~> docker network ls
NETWORK ID          NAME                DRIVER              SCOPE
64f4be5e2bbc        bridge              bridge              local
9b9ee0e5dd9c        docker_gwbridge     bridge              local
eafbd0580460        host                host                local
pti3tm6t2sr7        ingress             overlay             swarm
ffbzfzxwfxwh        mydrupal            overlay             swarm
a6ee62ad8781        none                null                local

• Create postgres service

[node1] ~> docker service create --name psql --network mydrupal -e POSTGRES_PASSWORD=mypass postgres
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[node1] ~> docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
y5v2pro56rtl        psql                replicated          1/1                 postgres:latest

[node1] ~> docker service ps y5v2pro56rtl
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
tswse0npw0i7        psql.1              postgres:latest     node1               Running             Running 2 minutes ago

• Create drupal service

[node1] ~> docker service create --name drupal --network mydrupal -p 80:80 drupal
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[node1] ~> docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE               PORTS
854hpf1t4w9u        drupal              replicated          1/1                 drupal:latest       *:80->80/tcp
y5v2pro56rtl        psql                replicated          1/1                 postgres:latest

[node1] ~> docker service ps drupal
ID                  NAME                IMAGE               NODE                DESIRED STATE       CURRENT STATE            ERROR               PORTS
hqbo9ejku1yo        drupal.1            drupal:latest       node2               Running             Running 47 seconds ago

• You can connect to drupal on any of the nodes IPs which is kinda cool