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Capsule supports databases running inside Docker containers. Instead of connecting over a network port, Capsule uses docker exec to run the dump command directly inside the container — no exposed port required.

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How it works

When you add a connection and specify a container name, Capsule:
  1. Runs docker exec <container> <dump-command> inside the container
  2. Streams the dump output to the host
  3. Encrypts and uploads the result — same as any other backup
The database tools (pg_dump, mysqldump, mongodump) must be present inside the container. Most official database images include them by default.

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Adding a Docker connection

In the Capsule TUI:
  1. Choose your database type (Postgres, MySQL, MongoDB)
  2. Fill in the connection details (host, port, credentials) as normal
  3. In the Docker container field, enter the container name or ID
Container name: my_postgres_container
Leave the container field blank for non-Docker connections.

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Find your container name

docker ps --format "table {{.Names}}\t{{.Image}}\t{{.Status}}"

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No exposed port needed

Because Capsule execs inside the container, the database port does not need to be published to the host (-p 5432:5432 is not required). This is safer — your database stays off the network.

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Docker Compose

If you use Docker Compose, the container name is typically <project>_<service>_1 or <project>-<service>-1 depending on your Compose version. 
# Find the exact name
docker compose ps

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Requirements

  • docker must be available in the PATH of the user running Capsule
  • The Capsule user must have permission to run docker exec (typically by being in the docker group)
# Add the capsule user to the docker group
sudo usermod -aG docker $USER
Run capsule doctor to verify Docker access.

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Troubleshooting

docker: permission denied Add the Capsule user to the docker group and log out/back in: 
sudo usermod -aG docker $USER
exec: pg_dump: executable file not found in container The dump tool is missing from the container image. Use a full database image (e.g., postgres:16) rather than a slim variant, or install the tools in the container. Container not found Double-check the container name with docker ps. The name is case-sensitive.