Docker Docker Networking docker network create docker network connect docker network inspect

1. Core Command / Concept

Create and manage Docker networks to isolate and connect containers. docker network create

2. Step-by-Step

1. Check if Docker is running: docker ps
2. Create a new network: docker network create my-network
3. Verify the network exists: docker network ls
4. Connect a container to the network: docker run -d --net=my-network my-image
5. Inspect the network: docker network inspect my-network
6. Disconnect a container from the network: docker network disconnect my-network container-id
7. Remove the network: docker network rm my-network
8. Clean up: docker rm $(docker ps -aq)

3. Real Commands with Examples

1. Purpose: Create a new network for a web application.
   Command: docker network create --driver=bridge --subnet=10.0.0.0/24 my-web-network Flags: --driver specifies the network driver, --subnet sets the network address range.
2. Purpose: Connect a container to an existing network.
   Command: docker run -d --net=my-web-network my-web-image Flags: --net specifies the network to connect to.
3. Purpose: Inspect a network to view its details.
   Command: docker network inspect my-web-network Flags: None, but you can specify the network name.

4. Common Errors

1. Error: Error response from daemon: network with name "my-network" already exists Why: You tried to create a network with a name that already exists.
   Fix: docker network rm my-network before recreating it.
2. Error: Error response from daemon: network "my-network" is not available Why: You tried to connect a container to a network that doesn't exist.
   Fix: docker network create my-network before connecting the container.
3. Error: Error response from daemon: container with id "container-id" is not connected to network "my-network" Why: You tried to disconnect a container from a network it's not connected to.
   Fix: docker network connect my-network container-id before disconnecting.

5. Quick Checks

1. Situation: You want to check if a container is connected to a network.
   Command: docker network inspect my-network Correct Response: The container's ID is listed under the "Containers" section.
2. Situation: You want to check if a network exists.
   Command: docker network ls Correct Response: The network name is listed in the output.
3. Situation: You want to check if a container is running.
   Command: docker ps Correct Response: The container's ID is listed in the output.

6. Last-Minute Reference

• docker network create flags: --driver, --subnet, --gateway • docker network inspect output: network name, ID, driver, subnet, gateway • docker network rm removes all networks by default; use docker network rm -f to force removal • docker network disconnect removes a container from a network; use docker network disconnect -f to force removal • docker network connect connects a container to a network; use docker network connect -f to force connection • docker network ls lists all networks; use docker network ls -f to filter by name or driver • docker network inspect output includes network statistics; use docker network inspect -v to view verbose output • docker network create creates a new network; use docker network create -d to specify the driver • docker network rm removes a network; use docker network rm -f to force removal • docker network disconnect removes a container from a network; use docker network disconnect -f to force removal