# Configure

> configure infra nodes, nginx, repo, dns, ntp, monitor system
---

The INFRA module primarily provides **monitoring** infrastructure and is [**optional**](/docs/install/minimal) for PostgreSQL service.

Unless you have manually configured dependencies on DNS/NTP services from INFRA nodes elsewhere, failures in the INFRA module typically won’t affect the normal operation of PostgreSQL database clusters.

In most cases, a single INFRA node is sufficient for typical scenarios. For production environments with higher requirements, we recommend using **2-3** INFRA nodes for high availability.

To improve resource utilization, PostgreSQL high availability typically relies on the [**`ETCD`**](/docs/etcd/) module, which can share nodes with the INFRA module.

Using more than 3 INFRA nodes provides limited benefits, but you can use more ETCD nodes (e.g., 5) to enhance the availability and reliability of DCS services.



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## Examples

To install the INFRA module on nodes, first add node IPs to the `infra` group in the [**inventory**](/docs/config/inventory) and assign them an Infra instance number [`infra_seq`](/docs/infra/param#infra_seq).

By default, a single INFRA node configuration meets most requirements. All configuration templates include a default `infra` group definition:

```yaml
all:
  children:
    infra: { hosts: { 10.10.10.10: { infra_seq: 1 } }}
```

The `10.10.10.10` IP placeholder in the `infra` group will be replaced with the [**current node’s primary IP address**](/docs/prepare/hardware#network) during [**configuration**](/docs/config/configure), meaning the INFRA module will be installed on the current node.

Then use the [`infra.yml`](/docs/infra/playbook/#infrayml) playbook to initialize the INFRA module on the node.

### More Nodes

To configure two INFRA nodes, add new IPs to `infra.hosts`:

```yaml
all:
  children:
    infra:
      hosts:
        10.10.10.10: { infra_seq: 1 }
        10.10.10.11: { infra_seq: 2 }
```

To configure three INFRA nodes with custom cluster/node parameters:

```yaml
all:
  children:
    infra:
      hosts:
        10.10.10.10: { infra_seq: 1 }
        10.10.10.11: { infra_seq: 2, repo_enabled: false }
        10.10.10.12: { infra_seq: 3, repo_enabled: false }
      vars:
        grafana_clean: false
        prometheus_clean: false
        loki_clean: false
```




------

## High Availability

Most components in the Infra module are “stateless/shared-state”. For these components, high availability primarily requires addressing load balancing.

Infra component load balancing can be achieved through two methods: Keepalived L2 VIP or HAProxy Layer 4 Load Balancing.

If your network environment supports Layer 2 connectivity, you can use Keepalived L2 VIP for high availability:

```yaml
infra:
  hosts:
    10.10.10.10: { infra_seq: 1 }
    10.10.10.11: { infra_seq: 2 }
    10.10.10.12: { infra_seq: 3 }
  vars:
    vip_enabled: true
    vip_vrid: 128
    vip_address: 10.10.10.8
    vip_interface: eth1

    infra_portal:
      home         : { domain: h.pigsty }
      grafana      : { domain: g.pigsty ,endpoint: "10.10.10.8:3000" , websocket: true }
      prometheus   : { domain: p.pigsty ,endpoint: "10.10.10.8:9058" }
      alertmanager : { domain: a.pigsty ,endpoint: "10.10.10.8:9059" }
      blackbox     : { endpoint: "10.10.10.8:9115" }
      loki         : { endpoint: "10.10.10.8:3100" }
```

In addition to configuring VIP-related parameters like [`vip_address`](/docs/node/param#vip_address), you need to modify endpoints for Infra services in [`infra_portal`](/docs/infra/param#infra_portal).