> ## Documentation Index
> Fetch the complete documentation index at: https://docs.pg-sharding.tech/llms.txt
> Use this file to discover all available pages before exploring further.

# SPQR Infra Mode

> Combined router and coordinator deployment for resource efficiency

🚧 **This section is under construction**

## Overview

SPQR Infra mode is a special deployment where each `spqr-router` instance acts as **both a router and a coordinator** in a single binary. This mode is ideal when you want to save CPU and memory resources or simplify your deployment architecture.

In SPQR Infra mode:

* A single `spqr-router` binary provides both routing and coordination functions
* Multiple instances form a distributed consensus group
* An etcd cluster is required for distributed state
* You should run an odd number of instances (1, 3, or 5)
* Reduced operational overhead compared to separate router and coordinator deployments

## Setup

### 1. Deploy etcd Cluster

Set up an etcd cluster to serve as the QDB. For production, we recommend using a 3-node cluster.

**Example: Single-node etcd (for testing)**

```bash theme={null}
etcd --listen-client-urls http://0.0.0.0:2379 \
     --advertise-client-urls http://localhost:2379
```

For production, follow the [etcd clustering guide](https://etcd.io/docs/latest/op-guide/clustering/).

🚧 **This section is under construction**