# Architecture

> Architecture and entities in the infra module
---

A standard Pigsty deployment comes with an [**`INFRA`**](/docs/infra/) module that provides the following services:

![](/img/pigsty/infra.png)

These are essential for a production-grade PostgreSQL service, and will be installed by default.

|      Component      |  Port  |   Domain   | Description                       |
|:-------------------:|:------:|:----------:|-----------------------------------|
|       `nginx`       |  `80`  | `h.pigsty` | Web Service Portal (YUM/APT Repo) |
|   `alertmanager`    | `9059` | `a.pigsty` | Alert Aggregation and delivery    |
|    `prometheus`     | `9058` | `p.pigsty` | Monitoring Time Series Database   |
|      `grafana`      | `3000` | `g.pigsty` | Visualization Platform            |
|       `loki`        | `3100` |     -      | Logging Collection Server         |
|    `pushgateway`    | `9091` |     -      | Collect One-Time Job Metrics      |
| `blackbox_exporter` | `9115` |     -      | ICMP, TCP, HTTP Probing           |
|      `dnsmasq`      |  `53`  |     -      | DNS Server, optional              |
|      `chronyd`      | `123`  |     -      | NTP Time Server, optional         |

**HA PG can be deployed without INFRA**

If you don't want these, the [**Minimal Install**](/docs/install/minimal) mode deploy HA Postgres without the Infra module.


- [Nginx](#nginx): Acts as a web server for local repo and a reverse proxy for other web UI services
- [Grafana](#grafana) : Visualization platform for metrics, dashboards, and data analytics
- [Loki](#loki): Centralized log aggregation and querying via Grafana
- [Prometheus](#prometheus): Time-series monitoring database for metrics collection, storage, and alert evaluation
- [AlertManager](#prometheus): Alert aggregation, notification dispatch, and silencing
- [PushGateway](#prometheus): Collects metrics from one-off and batch jobs
- [BlackboxExporter](#blackbox-exporter): Probes node IP and VIP reachability
- [DNSMASQ](#dnsmasq): DNS resolution for Pigsty’s internal domains
- [Chronyd](#chronyd): NTP time synchronization to keep all nodes in sync



The INFRA module isn’t mandatory for HA PostgreSQL - for instance, it’s omitted in [**Slim Install**](/docs/install/minimal) mode.

However, since INFRA provides essential supporting services for production-grade HA PostgreSQL clusters, it’s strongly recommended for most deployments.

If you already have your own infrastructure (Nginx, local repos, monitoring, DNS, NTP), you can disable INFRA and [**configure**](/docs/infra/config/) Pigsty to use your existing stack instead.


------



## Nginx

Nginx is the gateway for all WebUI services in Pigsty, serving on HTTP (80) / HTTPS (443) by default.

It exposes web UIs like Grafana, Prometheus, AlertManager, and HAProxy console, while also serving static resources like local yum/apt repos.

Nginx configuration follows [`infra_portal`](/docs/infra/param#infra_portal) definitions, for example:

```yaml
infra_portal:
  home         : { domain: h.pigsty }
  grafana      : { domain: g.pigsty ,endpoint: "${admin_ip}:3000" ,websocket: true }
  prometheus   : { domain: p.pigsty ,endpoint: "${admin_ip}:9058" }
  alertmanager : { domain: a.pigsty ,endpoint: "${admin_ip}:9059" }
  blackbox     : { endpoint: "${admin_ip}:9115" }
  loki         : { endpoint: "${admin_ip}:3100" }
  #minio        : { domain: sss.pigsty  ,endpoint: "${admin_ip}:9001" ,scheme: https ,websocket: true }
```

These `endpoint` definitions are referenced by other services - logs go to `loki` endpoint, Grafana datasources register to `grafana` endpoint, alerts route to `alertmanager` endpoint.

Pigsty allows rich Nginx customization as a local file server or reverse proxy, with self-signed or real HTTPS certs.

For more details, check these tutorials:

- [**Tutorial: DNS Configuration**](/docs/admin/domain)
- [**Tutorial: Nginx Service Exposure**](/docs/admin/portal)
- [**Tutorial: Certbot HTTPS Certificate Management**](/docs/admin/cert)



------

### Local Repo

During installation, Pigsty creates a local software repository on the INFRA node to speed up subsequent software installations.

Located at `/www/pigsty` and served by Nginx, it’s accessible via `http://h.pigsty/pigsty`.

Pigsty’s [offline package](/docs/install/offline) is a tarball of a pre-built repo directory. If `/www/pigsty` exists with a `/www/pigsty/repo_complete` marker, Pigsty skips downloading from upstream - perfect for air-gapped environments!

Repo definition lives in `/www/pigsty.repo`, fetchable via `http://${admin_ip}/pigsty.repo`:

```bash
curl -L http://h.pigsty/pigsty.repo -o /etc/yum.repos.d/pigsty.repo
```

You can also use the file repository directly without Nginx:

```ini
[pigsty-local]
name=Pigsty local $releasever - $basearch
baseurl=file:///www/pigsty/
enabled=1
gpgcheck=0
```

Local repo configs are in: [Config: INFRA - REPO](/docs/infra/param#repo)

------

### Prometheus

Prometheus, our TSDB for monitoring, listens on port 9058 (access via `IP:9058` or `http://p.pigsty`).

Key features:

- Service discovery via local static files with identity info
- Metric scraping, pre-processing, and TSDB storage
- Alert rule evaluation and forwarding to AlertManager

--------

## AlertManager

AlertManager handles alerts on port 9059 (`IP:9059` or `http://a.pigsty`). While it receives Prometheus alerts, you’ll need extra config (e.g., SMTP) for notifications.

Configs for Prometheus, AlertManager, PushGateway, and BlackboxExporter are in: [Config: INFRA - PROMETHEUS](/docs/infra/arch#prometheus)

------

### Grafana

Grafana, our visualization powerhouse, runs on port 3000 (`IP:3000` or `http://g.pigsty`).

Pigsty’s monitoring is dashboard-based with URL-driven navigation. Drill down or up quickly to pinpoint issues.

Fun fact: We’ve supercharged Grafana with extra viz plugins like ECharts - it’s not just monitoring, it’s a low-code data app platform!

Loki handles logs on port 3100, with Promtail shipping logs from nodes to the mothership.

Configs live in: [Config: INFRA - GRAFANA](/docs/infra/param#grafana) and [Config: INFRA - Loki](/docs/infra/param#loki)



------

### Ansible

Ansible is already installed on the [Admin Node](/docs/node/arch#admin-node) during [bootstrap](/docs/install/start#bootstrap).
So the `ansible` on [infra nodes](/docs/node/arch#infra-node) are not actually used.
But it gives you a viable backup option in case your admin node is compromised.

------

### DNSMASQ

DNSMASQ handles DNS resolution, with other modules registering their domains to INFRA’s DNSMASQ service.

DNS records live in `/etc/hosts.d/` on all INFRA nodes.

Configs: [Config: INFRA - DNS](/docs/infra/param#dns)

Pigsty sets it up just for your convenience, and Pigsty actually does NOT use it internally (static DNS records in `/etc/hosts` are used instead).


------

### Chronyd

Chronyd helps keep all nodes in sync!

NTP configs: [Config: NODES - NTP](/docs/node/param#node_time)

This is purely optional, if you already have your own NTP servers configured, just leave it alone.