How to get a Docker container’s IP address from the host ?

To get a Docker container’s IP address from the host, use the docker inspect command with a filter to extract the IP address. The method depends on whether the container uses the default bridge network or a custom network.

1. Basic Command (Default Bridge Network)

For containers using the default bridge network:

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' <container_name_or_id>

Example:

docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' my_container
# Output: 172.17.0.2

2. For a Specific Network

If the container is part of a custom network (e.g., my_network):

docker inspect -f '{{.NetworkSettings.Networks.my_network.IPAddress}}' <container_name_or_id>

Example:

docker inspect -f '{{.NetworkSettings.Networks.app_network.IPAddress}}' my_container
# Output: 192.168.1.5

3. List All IPs (All Networks)

To see IP addresses for all networks the container is connected to:

docker inspect -f '{{json .NetworkSettings.Networks}}' <container_name_or_id> | jq .

Example Output:

{
  "bridge": {
    "IPAddress": "172.17.0.2",
    ...
  },
  "my_custom_network": {
    "IPAddress": "192.168.1.5",
    ...
  }
}

4. Quick One-Liner

Use grep and awk for simplicity:

docker inspect <container_name_or_id> | grep -i "ipaddress" | awk '{print $2}' | head -n 1

5. Get Container IP via docker exec

Execute a command inside the container (requires hostname or ip tools):

docker exec <container_name_or_id> hostname -I
# Output: 192.168.1.5

Notes

• Default Bridge Network: The IP is usually in the 172.17.0.x range.
• Custom Networks: Use docker network ls to list networks and docker network inspect <network> for details.
• Docker Compose: Containers in a Compose project use a network named <project>_default. Adjust the network name accordingly.

Example Workflow

1. Find the container ID/name:

   docker ps

2. Get the IP:

   docker inspect -f '{{.NetworkSettings.Networks.my_network.IPAddress}}' my_container

Use these commands to efficiently retrieve container IPs for debugging or networking tasks!