# FAQ

> frequently asked questions
---

## Who Can Run Docker Commands?

By default, Pigsty adds both the **management user** running the playbook on the remote host (i.e., the SSH login user) and the user defined by the [`node_admin_username`](/docs/node/param#node_admin_username) parameter to the operating-system group **`docker`**.
 Any account in this group can manage Docker via the `docker` CLI.

Need to grant another user Docker access? Just add that OS user to the **`docker`** group:

```bash
sudo usermod -aG docker <username>
```

------

## Working Through a Proxy

During installation, if the [`proxy_env`](/docs/infra/param#proxy_env) parameter is set, Pigsty writes the specified HTTP proxy settings to `/etc/docker/daemon.json`.

Docker will then route all image pulls from upstream registries through this proxy.

**Tip:** Running the `configure` playbook with the `-x` flag automatically captures your current shell's proxy variables and injects them into `proxy_env`.

------

## Using Mirror Registries

Inside mainland China you may encounter Great Firewall restrictions. Historically, mirrors such as **quay.io** could be used:

```bash
docker login quay.io   # enter your credentials to log in
```

> **Update (June 2024):** All previously accessible Docker mirrors in China have now been blocked. Please pull images via a proxy.

------

## Adding Docker to Monitoring

When the Docker module is installed, you can register Docker as a Prometheus target for a specific node by running the **`docker_register`** (alias **`register_prometheus`**) task:

```bash
./docker.yml -l <your-node-selector> -t register_prometheus
```

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## Software Templates

Pigsty ships a collection of [software templates](/docs/app/) that launch popular stacks with **Docker Compose**—ready to use out of the box.

Just make sure the Docker module is installed first.