Docker Overlay Driver and Overlay Networking

1. What is overlay networking in Docker?
2. How do you create a network overlay?
3. What is Docker Network Driver?
4. How do you communicate between two Docker containers in separate networks?
5. How does network overlay work?
6. What is overlay and underlay?
7. What is overlay routing?
8. What is meant by overlay network?
9. Which statement is true about overlay network?
10. What is the Docker subnet?
11. Does Docker use NAT?
12. What is Bridge Docker?

What is overlay networking in Docker?

The overlay network driver creates a distributed network among multiple Docker daemon hosts. This network sits on top of (overlays) the host-specific networks, allowing containers connected to it (including swarm service containers) to communicate securely when encryption is enabled.

How do you create a network overlay?

Use a user-defined overlay network

1. Create the user-defined overlay network. ...
2. Start a service using the overlay network and publishing port 80 to port 8080 on the Docker host. ...
3. Run docker network inspect my-overlay and verify that the my-nginx service task is connected to it, by looking at the Containers section.

What is Docker Network Driver?

In between applications and the network sits Docker networking, affectionately called the Container Network Model or CNM. ... The most commonly used built-in network drivers are bridge, overlay and macvlan. Together they cover a very broad list of networking use cases and environments.

How do you communicate between two Docker containers in separate networks?

3 Answers. Containers in different networks can not communicate with each other because iptables drop such packets. This is shown in the DOCKER-ISOLATION-STAGE-1 and DOCKER-ISOLATION-STAGE-2 chains in the filter table. Rules can be added to DOCKER-USER chain to allow communication between different networks.

How does network overlay work?

Simply put, an overlay network is a virtual network of nodes and logical links, which are built on top of an existing network. Using overlay networks, multiple layers of network abstraction can be created to run virtualized network layers, which are supported by a physical infrastructure.

What is overlay and underlay?

An overlay network is formed on top of the underlay in direction to construct a virtualized network. The data plane traffic and control plane signaling is controlled within each virtualized network, upholding segregation between the networks in accumulation to freedom from the underlay network.

What is overlay routing?

1. The concept of using an overlay network to route packets, as a result packets will follow a different route than when the normal direct Internet route is followed.

What is meant by overlay network?

An overlay network is a communication network constructed on top of an another communication network. The nodes of the overlay network are interconnected with logical connections, which form an overlay topology.

Which statement is true about overlay network?

Answer : Overlay networks are first created on the manager nodes. Then they are created on the worker nodes once a task is scheduled on the specific worker node.

What is the Docker subnet?

Summary. Docker uses the default 172.17. 0.0/16 subnet for container networking. If this subnet is not available for docker in your environment (for example because your network already uses this subnet), you must configure Docker to use a different subnet.

Does Docker use NAT?

It randomly chooses an address and subnet from a private defined range. All the Docker containers are connected to this bridge and use the NAT rules created by docker to communicate with the outside world.

What is Bridge Docker?

In terms of Docker, a bridge network uses a software bridge which allows containers connected to the same bridge network to communicate, while providing isolation from containers which are not connected to that bridge network. ... Bridge networks apply to containers running on the same Docker daemon host.