FHS: File Hierarchy Structure

Historical documentation restored from the Pigsty v1.5.1 tag.

Pigsty FHS

#------------------------------------------------------------------------------
# pigsty
#  ^-----@app                    # extra demo application resources
#  ^-----@bin                    # bin scripts
#  ^-----@docs                   # document (can be docsified)
#  ^-----@files                  # ansible file resources
#            ^-----@conf         # config template files
#            ^-----@rule         # soft link to prometheus rules
#            ^-----@ui           # soft link to grafana dashboards
#  ^-----@roles                  # ansible business logic
#  ^-----@templates              # ansible templates
#  ^-----@vagrant                # sandbox resources
#  ^-----configure               # configure wizard script
#  ^-----ansible.cfg             # default ansible config file
#  ^-----pigsty.yml              # default config file
#  ^-----*.yml                   # ansible playbooks

#------------------------------------------------------------------------------
# /etc/pigsty/
#  ^-----@targets                # file based service discovery targets definition
#  ^-----@dashboards             # static grafana dashboards
#  ^-----@datasources            # static grafana datasources
#  ^-----@playbooks              # extra ansible playbooks
#------------------------------------------------------------------------------

Prometheus FHS

#------------------------------------------------------------------------------
# Config FHS
#------------------------------------------------------------------------------
# /etc/prometheus/
#  ^-----prometheus.yml              # prometheus main config file
#  ^-----alertmanager.yml            # alertmanger main config file
#  ^-----@bin                        # util scripts: check,reload,status,new
#  ^-----@rules                      # record & alerting rules definition
#            ^-----@infra            # infrastructure rules & alert
#            ^-----@nodes            # nodes rules & alert
#            ^-----@pgsql            # pgsql rules & alert
#            ^-----@redis            # redis rules & alert
#            ^-----@..........       # etc...
#  ^-----@targets                    # file based service discovery targets definition
#            ^-----@infra            # infra static targets definition
#            ^-----@nodes            # nodes static targets definition
#            ^-----@pgsql            # pgsql static targets definition
#            ^-----@redis            # redis static targets definition
#            ^-----@.....            # other targets
#------------------------------------------------------------------------------

Postgres FHS

The following parameters are related to the PostgreSQL database dir:

pg_dbsu_home: Postgres default user’s home dir, default is /var/lib/pgsql.
pg_bin_dir: Postgres binary dir, defaults to /usr/pgsql/bin/.
pg_data: Postgres database dir, default is /pg/data.
pg_fs_main: Postgres main data disk mount point, default is /export.
pg_fs_bkup: Postgres backup disk mount point, default is /var/backups (optional, you can also choose to backup to a subdirectory on the primary data disk).

#------------------------------------------------------------------------------
# Create Directory
#------------------------------------------------------------------------------
# this assumes that
#   /pg is shortcut for postgres home
#   {{ pg_fs_main }} contains the main data             (MUST ALREADY MOUNTED)
#   {{ pg_fs_bkup }} contains archive and backup data   (MUST ALREADY MOUNTED)
#   cluster-version is the default parent folder for pgdata (e.g pg-test-12)
#------------------------------------------------------------------------------
# default variable:
#     pg_fs_main = /export           fast ssd
#     pg_fs_bkup = /var/backups      cheap hdd
#
#     /pg      -> /export/postgres/pg-test-12
#     /pg/data -> /export/postgres/pg-test-12/data
#------------------------------------------------------------------------------
- name: Create postgresql directories
  tags: pg_dir
  become: yes
  block:
    - name: Make sure main and backup dir exists
      file: path={{ item }} state=directory owner=root mode=0777
      with_items:
        - "{{ pg_fs_main }}"
        - "{{ pg_fs_bkup }}"

    # pg_cluster_dir:    "{{ pg_fs_main }}/postgres/{{ pg_cluster }}-{{ pg_version }}"
    - name: Create postgres directory structure
      file: path={{ item }} state=directory owner={{ pg_dbsu }} group=postgres mode=0700
      with_items:
        - "{{ pg_fs_main }}/postgres"
        - "{{ pg_cluster_dir }}"
        - "{{ pg_cluster_dir }}/bin"
        - "{{ pg_cluster_dir }}/log"
        - "{{ pg_cluster_dir }}/tmp"
        - "{{ pg_cluster_dir }}/conf"
        - "{{ pg_cluster_dir }}/data"
        - "{{ pg_cluster_dir }}/meta"
        - "{{ pg_cluster_dir }}/stat"
        - "{{ pg_cluster_dir }}/change"
        - "{{ pg_backup_dir }}/postgres"
        - "{{ pg_backup_dir }}/arcwal"
        - "{{ pg_backup_dir }}/backup"
        - "{{ pg_backup_dir }}/remote"

PG Binary FHS

On RedHat/CentOS, the default installation location for the Postgres distribution is:

/usr/pgsql-${pg_version}/

The installation playbook automatically creates a soft link to the currently installed version. For example, if version 14 of Postgres is installed, there are.

/usr/pgsql -> /usr/pgsql-14

Therefore, the default pg_bin_dir is /usr/pgsql/bin/, and this path is added to the PATH environment variable for all users in /etc/profile.d/pgsql.sh.

PG Data FHS

Pigsty assumes at least one primary data disk (pg_fs_main) and an optional backup data disk (pg_fs_bkup) on the single node used to deploy the database instance. Usually, the primary data disk is a high-performance SSD, while the backup disk is a high-capacity inexpensive HDD.

#------------------------------------------------------------------------------
# Create Directory
#------------------------------------------------------------------------------
# this assumes that
#   /pg is shortcut for postgres home
#   {{ pg_fs_main }} contains the main data             (MUST ALREADY MOUNTED)
#   {{ pg_fs_bkup }} contains archive and backup data   (MAYBE ALREADY MOUNTED)
#   {{ pg_cluster }}-{{ pg_version }} is the default parent folder
#    for pgdata (e.g pg-test-14)
#------------------------------------------------------------------------------
# default variable:
#     pg_fs_main = /export           fast ssd
#     pg_fs_bkup = /var/backups      cheap hdd
#
#     /pg      -> /export/postgres/pg-test-14
#     /pg/data -> /export/postgres/pg-test-14/data

PG Cluster FHS

# basic
{{ pg_fs_main }}     /data                      # contains all business data (pg,consul,etc..)
{{ pg_dir_main }}    /data/postgres             # contains postgres main data
{{ pg_cluster_dir }} /data/postgres/pg-test-14  # contains cluster `pg-test` data (of version 13)
                     /data/postgres/pg-test-14/bin            # binary scripts
                     /data/postgres/pg-test-14/log            # misc logs
                     /data/postgres/pg-test-14/tmp            # tmp, sql files, records
                     /data/postgres/pg-test-14/conf           # configurations
                     /data/postgres/pg-test-14/data           # main data directory
                     /data/postgres/pg-test-14/meta           # identity information
                     /data/postgres/pg-test-14/stat           # stats information
                     /data/postgres/pg-test-14/change         # changing records

{{ pg_fs_bkup }}     /var/backups                      # contains all backup data (pg,consul,etc..)
{{ pg_dir_bkup }}    /var/backups/postgres             # contains postgres backup data
{{ pg_backup_dir }}  /var/backups/postgres/pg-test-14  # contains cluster `pg-test` backup (of version 13)
                     /var/backups/postgres/pg-test-14/backup   # base backup
                     /var/backups/postgres/pg-test-14/arcwal   # WAL archive
                     /var/backups/postgres/pg-test-14/remote   # mount NFS/S3 remote resources here

# links
/pg             -> /data/postgres/pg-test-14                 # pg root link
/pg/data        -> /data/postgres/pg-test-14/data            # real data dir
/pg/backup      -> /var/backups/postgres/pg-test-14/backup   # base backup
/pg/arcwal      -> /var/backups/postgres/pg-test-14/arcwal   # WAL archive
/pg/remote      -> /var/backups/postgres/pg-test-14/remote   # mount NFS/S3 remote resources here

Pgbouncer FHS

Pgbouncer is run using the Postgres user, and the config file is located in /etc/pgbouncer. The config file includes.

pgbouncer.ini: the main config file
userlist.txt: lists the users in the connection pool
pgb_hba.conf: lists the access privileges of the connection pool users
database.txt: lists the databases in the connection pool

Redis FHS

Pigsty provides essential support for Redis deployment and monitoring.

Redis binaries are installed in /bin/ using RPM-packages or copied binaries, including:

redis-server
redis-server
redis-cli
redis-sentinel
redis-check-rdb
redis-check-aof
redis-benchmark
/usr/libexec/redis-shutdown

For a Redis instance named redis-test-1-6379, the resources associated with it are shown below:

/usr/lib/systemd/system/redis-test-1-6379.service               # Services
/etc/redis/redis-test-1-6379.conf                               # Config
/data/redis/redis-test-1-6379                                   # Database Catalog
/data/redis/redis-test-1-6379/redis-test-1-6379.rdb             # RDB File
/data/redis/redis-test-1-6379/redis-test-1-6379.aof             # AOF file
/var/log/redis/redis-test-1-6379.log                            # Log
/var/run/redis/redis-test-1-6379.pid                            # PID