# Configuration > Describe database and infrastructure as code using declarative Configuration --- **Pigsty treats Infra & Database as Code.** You can describe the infrastructure & database clusters through a declarative interface. All your essential work is to describe your need in the [inventory](#inventory), then materialize it with a simple idempotent playbook. ---------------- ## Inventory Each pigsty deployment has a corresponding config **inventory**. It could be stored in a local git-managed file in [YAML](https://docs.ansible.com/ansible/2.9/user_guide/playbooks_variables.html) format or dynamically generated from [CMDB](https://docs.ansible.com/ansible/2.9/user_guide/intro_dynamic_inventory.html) or any ansible compatible format. Pigsty uses a monolith YAML config file as the default config inventory, which is [`pigsty.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/pigsty.yml), [located](https://github.com/Vonng/pigsty/blob/v2.7.0/ansible.cfg#L3) in the pigsty home directory. The inventory consists of two parts: **global vars** & multiple **group definitions**. You can define new clusters with inventory groups: `all.children`. And describe infra and set global default parameters for clusters with global vars: `all.vars`. Which may look like this: ```yaml all: # Top-level object: all vars: {...} # Global Parameters children: # Group Definitions infra: # Group Definition: 'infra' hosts: {...} # Group Membership: 'infra' vars: {...} # Group Parameters: 'infra' etcd: {...} # Group Definition: 'etcd' pg-meta: {...} # Group Definition: 'pg-meta' pg-test: {...} # Group Definition: 'pg-test' redis-test: {...} # Group Definition: 'redis-test' # ... ``` There are lots of config examples under [`files/pigsty`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/README.md) ---------------- ## Cluster Each group may represent a cluster, which could be a Node cluster, PostgreSQL cluster, Redis cluster, Etcd cluster, or Minio cluster, etc... They all use the same format: **group vars** & **hosts**. You can define cluster members with `all.children..hosts` and describe cluster with cluster parameters in `all.children..vars`. Here is an example of 3 nodes PostgreSQL HA cluster named `pg-test`: ```yaml pg-test: # Group Name vars: # Group Vars (Cluster Parameters) pg_cluster: pg-test hosts: # Group Host (Cluster Membership) 10.10.10.11: { pg_seq: 1, pg_role: primary } # Host1 10.10.10.12: { pg_seq: 2, pg_role: replica } # Host2 10.10.10.13: { pg_seq: 3, pg_role: offline } # Host3 ``` You can also define parameters for a specific host, as known as **host vars**. It will override group vars and global vars. Which is usually used for assigning identities to nodes & database instances. ---------------- ## Parameter Global vars, Group vars, and Host vars are dict objects consisting of a series of K-V pairs. Each pair is a named **Parameter** consisting of a string name as the key and a value of one of five types: boolean, string, number, array, or object. Check parameter reference for detailed syntax & semantics. Every parameter has a proper default value except for mandatory **IDENTITY PARAMETERS**; they are used as identifiers and must be set explicitly, such as [`pg_cluster`](/docs/reference/param/#pg_cluster), [`pg_role`](/docs/reference/param/#pg_role), and [`pg_seq`](/docs/reference/param/#pg_seq). Parameters can be specified & overridden with the following precedence. ```bash Playbook Args > Host Vars > Group Vars > Global Vars > Defaults ``` For examples: * Force removing existing databases with Playbook CLI Args `-e pg_clean=true` * Override an instance role with Instance Level Parameter `pg_role` on Host Vars * Override a cluster name with Cluster Level Parameter `pg_cluster` on Group Vars. * Specify global NTP servers with Global Parameter `node_ntp_servers` on Global Vars * If no `pg_version` is set, it will use the default value from role implementation (16 by default) ---------------- ## Template There are numerous preset config templates for different scenarios under the [`files/pigsty`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/README.md) directory. During [`configure`](/docs/setup/install#configure) process, you can specify a template using the -m parameter. Otherwise, the single-node installation config template will be automatically selected based on your OS distribution. - EL 8 / 9: [`el8.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/el8.yml) / [`el9.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/el9.yml) - Debian 12: [`debian12.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/debian12.yml) - Ubuntu 22.04 jammy: [`ubuntu22.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/ubuntu22.yml) Although the Pigsty no longer officially supports these OS distros, you can still use the following templates for older major OS versions to perform online installation: - EL 7：[`el7.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/el7.yml) - Debian 11 bullseye: [`debian11.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/debian11.yml) - Ubuntu 20.04 focal：[`ubuntu20.yml`](https://github.com/Vonng/pigsty/blob/v2.7.0/files/pigsty/ubuntu20.yml) ---------------- ## Switch Config Inventory To use a different config inventory, you can copy & paste the content into the `pigsty.yml` file in the home dir as needed. You can also explicitly specify the config inventory file to use when executing Ansible playbooks by using the `-i` command-line parameter, for example: ```bash ./node.yml -i files/pigsty/rpmbuild.yml # use another file as config inventory, rather than the default pigsty.yml ``` If you want to modify the **default** config inventory filename, you can change the `inventory` parameter in the [`ansible.cfg`](https://github.com/Vonng/pigsty/blob/v2.7.0/ansible.cfg#L6) file in the home dir to point to your own inventory file path. This allows you to run the `ansible-playbook` command without explicitly specifying the `-i` parameter. Pigsty allows you to use a database (CMDB) as a dynamic configuration source instead of a static configuration file. Pigsty provides three convenient scripts: - [`bin/inventory_load`](https://github.com/Vonng/pigsty/blob/v2.7.0/bin/inventory_load): Loads the content of the `pigsty.yml` into the local PostgreSQL database (`meta`.`pigsty`) - [`bin/inventory_cmdb`](https://github.com/Vonng/pigsty/blob/v2.7.0/bin/inventory_cmdb): Switches the configuration source to the local PostgreSQL database (`meta`.`pigsty`) - [`bin/inventory_conf`](https://github.com/Vonng/pigsty/blob/v2.7.0/bin/inventory_cmdb): Switches the configuration source to the local static configuration file `pigsty.yml` ---------------- ## Reference Pigsty have 280+ parameters, check [Parameter](/docs/reference/param/) for details. | Module | Section | Description | Count | |:-----------------------------------------:|---------------------------------------------------------|----------------------------------|-------| | [`INFRA`](/docs/reference/param/#infra) | [`META`](/docs/reference/param/#meta) | Pigsty Metadata | 4 | | [`INFRA`](/docs/reference/param/#infra) | [`CA`](/docs/reference/param/#ca) | Self-Signed CA | 3 | | [`INFRA`](/docs/reference/param/#infra) | [`INFRA_ID`](/docs/reference/param/#infra_id) | Infra Portals & Identity | 2 | | [`INFRA`](/docs/reference/param/#infra) | [`REPO`](/docs/reference/param/#repo) | Local Software Repo | 9 | | [`INFRA`](/docs/reference/param/#infra) | [`INFRA_PACKAGE`](/docs/reference/param/#infra_package) | Infra Packages | 2 | | [`INFRA`](/docs/reference/param/#infra) | [`NGINX`](/docs/reference/param/#nginx) | Nginx Web Server | 7 | | [`INFRA`](/docs/reference/param/#infra) | [`DNS`](/docs/reference/param/#dns) | DNSMASQ Nameserver | 3 | | [`INFRA`](/docs/reference/param/#infra) | [`PROMETHEUS`](/docs/reference/param/#prometheus) | Prometheus Stack | 18 | | [`INFRA`](/docs/reference/param/#infra) | [`GRAFANA`](/docs/reference/param/#grafana) | Grafana Stack | 6 | | [`INFRA`](/docs/reference/param/#infra) | [`LOKI`](/docs/reference/param/#loki) | Loki Logging Service | 4 | | [`NODE`](/docs/reference/param/#node) | [`NODE_ID`](/docs/reference/param/#node_id) | Node Identity Parameters | 5 | | [`NODE`](/docs/reference/param/#node) | [`NODE_DNS`](/docs/reference/param/#node_dns) | Node domain names & resolver | 6 | | [`NODE`](/docs/reference/param/#node) | [`NODE_PACKAGE`](/docs/reference/param/#node_package) | Node Repo & Packages | 5 | | [`NODE`](/docs/reference/param/#node) | [`NODE_TUNE`](/docs/reference/param/#node_tune) | Node Tuning & Kernel features | 10 | | [`NODE`](/docs/reference/param/#node) | [`NODE_ADMIN`](/docs/reference/param/#node_admin) | Admin User & Credentials | 7 | | [`NODE`](/docs/reference/param/#node) | [`NODE_TIME`](/docs/reference/param/#node_time) | Node Timezone, NTP, Crontabs | 5 | | [`NODE`](/docs/reference/param/#node) | [`NODE_VIP`](/docs/reference/param/#node_vip) | Node Keepalived L2 VIP | 8 | | [`NODE`](/docs/reference/param/#node) | [`HAPROXY`](/docs/reference/param/#haproxy) | HAProxy the load balancer | 10 | | [`NODE`](/docs/reference/param/#node) | [`NODE_EXPORTER`](/docs/reference/param/#node_exporter) | Node Monitoring Agent | 3 | | [`NODE`](/docs/reference/param/#node) | [`PROMTAIL`](/docs/reference/param/#promtail) | Promtail logging Agent | 4 | | [`DOCKER`](/docs/reference/param/#docker) | [`DOCKER`](/docs/reference/param/#docker) | Docker Daemon | 4 | | [`ETCD`](/docs/reference/param/#etcd) | [`ETCD`](/docs/reference/param/#etcd) | ETCD DCS Cluster | 10 | | [`MINIO`](/docs/reference/param/#minio) | [`MINIO`](/docs/reference/param/#minio) | MINIO S3 Object Storage | 15 | | [`REDIS`](/docs/reference/param/#redis) | [`REDIS`](/docs/reference/param/#redis) | Redis the key-value NoSQL cache | 20 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_ID`](/docs/reference/param/#pg_id) | PG Identity Parameters | 11 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_BUSINESS`](/docs/reference/param/#pg_business) | PG Business Object Definition | 12 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_INSTALL`](/docs/reference/param/#pg_install) | Install PG Packages & Extensions | 10 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_BOOTSTRAP`](/docs/reference/param/#pg_bootstrap) | Init HA PG Cluster with Patroni | 39 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_PROVISION`](/docs/reference/param/#pg_provision) | Create in-database objects | 9 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_BACKUP`](/docs/reference/param/#pg_backup) | Set Backup Repo with pgBackRest | 5 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_SERVICE`](/docs/reference/param/#pg_service) | Exposing service, bind vip, dns | 9 | | [`PGSQL`](/docs/reference/param/#pgsql) | [`PG_EXPORTER`](/docs/reference/param/#pg_exporter) | PG Monitor agent for Prometheus | 15 |