What is an overlay network and how does DNS resolution work?

Question

I cannot connect to an external server mongodbfrom my cluster docker swarm.

As I understand it, this is due to the fact that the cluster uses a network overlay driver. I'm right?

If not, how does the docker overlay driver work and how can I connect to an external server mongodbfrom a cluster?

Answer 1

Q. How does the docker overlay driver work?

I would recommend this good link for understanding the overlay network of road dockers and more globally how docker is archived .

It means that:

Docker DNS , Docker Engine, , Docker Swarm. Docker Engine DNS-, , MACVLAN.

Docker ( Swarm) DNS-, DNS- Docker Engine, DNS-.

, multi-host docker swarm mode, :

myservice. (client) . client curl docker.com myservice.

:

• DNS- client docker.com myservice.
• DNS- 127.0.0.11:53 DNS- Docker Engine.
• myservice IP (VIP) , IP- . , IP-.
• docker.com mynet, DNS- .

:

mongodb?

mongodb (, DNS mongodb.mydomain.com), , client , docker.com, , , , mongodb.mydomain.com , DNS- .

, docker DNS- mongodb.mydomain.com?

docker service, DNS- , :

docker service create \
--name myservice \
--network my-overlay-network \
--dns=10.0.0.2 \
myservice:latest

--dns=10.0.0.2. docker DNS- 10.0.0.2:53 , DNS- VIP.

, :

mongodb . , , . ?

"", docker engine DNS overlay network DNS-.

, !