> ## Documentation Index
> Fetch the complete documentation index at: https://3to1go.docs.thesteau.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Install Central

> Run Central and its PostgreSQL database with Docker Compose.

Central ships as a Docker image, `ghcr.io/thesteau/3to1go-central`, and needs PostgreSQL. The example deployment in the repository runs both.

## Requirements

* Docker with Compose
* Enough disk for your snapshots (Central keeps full archives; see [retention](/central/snapshots#retention))
* A port Edges can reach, `6555` by default

## Set up

<Steps>
  <Step title="Get the example files">
    ```sh theme={null}
    mkdir 3to1go-central && cd 3to1go-central
    curl -fsSLO https://raw.githubusercontent.com/thesteau/3to1go/main/deploy-example/central/docker-compose.yml
    curl -fsSL  https://raw.githubusercontent.com/thesteau/3to1go/main/deploy-example/central/.env.example -o .env
    ```

    Or copy [`deploy-example/central/`](https://github.com/thesteau/3to1go/tree/main/deploy-example/central) from GitHub.
  </Step>

  <Step title="Edit .env">
    ```sh .env theme={null}
    # Host folder mounted into Central at /backups.
    BACKUP_DIR=./data/backups
    POSTGRES_DB=three_to_one_go
    POSTGRES_USER=three_to_one_go
    POSTGRES_PASSWORD=change-this-password
    # Only used when Central creates the first admin user.
    INITIAL_ADMIN_PASSWORD=admin
    ```

    Set a real `POSTGRES_PASSWORD`. Point `BACKUP_DIR` at wherever snapshots should live; see [Storage](/concepts/storage-and-3-2-1#where-central-can-store-snapshots).
  </Step>

  <Step title="Start it">
    ```sh theme={null}
    docker compose up -d
    ```

    Central waits for PostgreSQL to be healthy before starting.
  </Step>

  <Step title="Sign in">
    Open `http://<central-host>:6555/` and sign in as `admin`. See [Sign-in and accounts](/shared/sign-in).
  </Step>

  <Step title="Connect your first Edge">
    Click **Mint Edge Credential** and paste the result into Edge. See [Edge credentials](/central/edge-credentials).
  </Step>
</Steps>

## What gets created

The example Compose file keeps everything next to it:

```text theme={null}
3to1go-central/
├── docker-compose.yml
├── .env
├── config/          # issuer.key, trusted-certs/
├── hook-scripts/    # scripts for Custom Scripts
├── secrets/         # mounted at /run/secrets
└── data/
    ├── backups/     # snapshots (unless BACKUP_DIR points elsewhere)
    ├── staging/     # uploads in progress
    └── postgres/    # database files
```

<Warning>
  Preserve `config/` (it holds `issuer.key`) and a consistent backup of PostgreSQL, as well as the snapshot folder. Stop PostgreSQL before copying its data directory, or use PostgreSQL's backup tools. Losing the database loses snapshot metadata, users, and credential records; losing `issuer.key` invalidates every Edge credential.
</Warning>

## Update

```sh theme={null}
docker compose pull
docker compose up -d
```

## Build from source

To build the image yourself, use the Compose file in [`central/`](https://github.com/thesteau/3to1go/tree/main/central) instead. It builds from the repository root so the shared code is included.