# Concept

> Learn about core concept about Pigsty: architecture, cluster models, infra, PG HA, PITR, and service access.
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Section pages:

- [Architecture](/docs/concept/arch/): Pigsty's modular architecture, compose modules in a declarative manner
- [Cluster Model](/docs/concept/model/): Pigsty abstracts different types of functionalities into modules & clusters.
- [Monitor System](/docs/concept/monitor/): The architecture and implementation of Pigsty's monitoring system, the service discovery details
- [Self-Signed CA](/docs/concept/ca/): Pigsty comes with a set of self-signed CA PKI for issuing SSL certs to encrypt network traffic.
- [Infra as Code](/docs/concept/iac/): Pigsty treat infra & database as code. Manage them in a declarative manner
- [High Availability](/docs/concept/ha/): Pigsty uses Patroni to achieve high availability for PostgreSQL, ensuring automatic failover.
- [Point-in-Time Recovery](/docs/concept/pitr/): Pigsty utilizes pgBackRest for PostgreSQL point-in-time recovery, allowing users to roll back to any point within the backup policy limits.
- [Services & Access](/docs/concept/svc/): Pigsty employs HAProxy for service access, offering optional pgBouncer for connection pooling, and optional L2 VIP and DNS access.
- [Access Control](/docs/concept/ac/): Pigsty has moderate security best-practice: password & certs, built-in ACLs, encrypted network traffics and cold backups