Instance configuration#

This is an overview of the TPA settings you can use to customize the deployment process on cluster instances.

There’s also an overview of configuring a cluster , which explains how to use cluster and instance variables together to write a concise, easy-to-review config.yml .

System-level configuration#

The first thing TPA does is to ensure that Python is bootstrapped and ready to execute Ansible modules (a distribution-specific process). Then it completes various system-level configuration tasks before it

configures Postgres .

  • :ref:`Distribution support <Distribution support>`

  • :ref:`Setting up the TPA Python environment <Setting up the TPA Python environment>`  (`preferred_python_version` )

  • :ref:`Environment variables <Environment>`  (for example, `https_proxy` )

Package repositories#

You can use the pre-deploy hook

to execute tasks before any package repositories are configured.

  • :ref:`Configure YUM repositories <Configuring YUM repositories>`

(for RHEL, Rocky, and AlmaLinux)

  • :ref:`Configure APT repositories <Configuring APT repositories>`

(for Debian and Ubuntu)

  • :ref:`Configure 2ndQuadrant and EDB repositories <How TPA uses 2ndQuadrant and EDB repositories>`

(on any system)

  • :ref:`Configure a local package repository <Creating and using a local repository>`

(to ship packages to target instances)

You can use the post-repo hook

to execute tasks after package repository configuration. For example, you can use it to correct a problem with the repository configuration before installing any packages.

Package installation#

Once the repositories are configured, packages are installed at various stages throughout the deployment, beginning with a batch of system packages:

  • :ref:`Install non-Postgres packages <Installing packages>`

(for example, acl, openssl, sysstat)

Postgres and other components (for example, Barman, repmgr, pgbouncer) are installed separately according to the cluster configuration. See

Other system-level tasks#

  • :ref:`Create and mount file systems <Filesystem configuration>`  (including RAID, LUKS setup)

  • :ref:`Upload artifacts <Uploading artifacts>`  (files, directories, tar archives)

  • :ref:`Set sysctl values <Setting sysctl values>`

  • :ref:`Configure /etc/hosts <Configuring /etc/hosts>`

  • :ref:`Manage ssh_known_hosts entries <Managing SSH host keys>`

  • :ref:`Add system locale <Locale>`

Postgres#

Postgres configuration is an extended process that’s interleaved with the configuration of other components like repmgr and pgbouncer. The first step is to install Postgres.

Version selection#

Use the configure options to select a Postgres flavor and version, or set postgres_version in config.yml to specify the Postgres major version you want to install.

That’s all you need to do to set up a working cluster. Everything else described here is optional. You can control every aspect of the deployment if you want to, but the defaults are carefully selected to give you a sensible cluster as a starting point.

Installation#

The default postgres_installation_method is to install packages for the version of Postgres you selected, along with various extensions, according to the architecture’s needs:

  • :ref:`Install Postgres and Postgres-related packages <Installing Postgres-related packages>`

(for example, pglogical, BDR, and so on)

  • :ref:`Build and install Postgres and extensions from source <Postgres source installation>`

(for development and testing)

Whichever installation method you choose, TPA can give you the same cluster configuration with a minimum of effort.

Configuration#

  • :ref:`Configure the postgres Unix user <The postgres Unix user>`

  • :ref:`Run initdb to create the PGDATA directory <Running initdb>`

  • :ref:`Configure pg_hba.conf <pg_hba.conf>`

  • :ref:`Configure pg_ident.conf <pg_ident.conf>`

  • :ref:`Configure postgresql.conf <postgresql.conf>`

You can use the postgres-config hook

to execute tasks after the Postgres configuration files are installed (for example, to install additional configuration files).

Once the Postgres configuration is in place, TPA installs and configures other components, such as Barman, repmgr, pgbouncer, and haproxy, according to the details of the architecture.

Other components#

  • :ref:`Configure Barman <Barman>`

  • :ref:`Configure pgbouncer <Configuring pgbouncer>`

  • :ref:`Configure haproxy <Configuring haproxy>`

  • :ref:`Configure HARP <Configuring HARP>`

  • :ref:`Configure EFM <Configuring EFM>`

Configuring and starting services#

TPA installs systemd service unit files for each service. The service for Postgres is named postgres.service . You can use systemctl start postgres to start it and systemctl stop postgres to stop it.

If you’re deploying a cluster for the first time, TPA starts the Postgres service at this point. On an existing cluster, if there are any relevant configuration changes, TPA reloads or restarts the Postgres service as appropriate. If there are no changes and Postgres is already running, it leaves the service alone. (If Postgres isn’t running on an existing cluster, TPA starts it.)

In any case, Postgres is running at the end of this step.

After starting Postgres#

  • :ref:`Create Postgres users <The postgres Unix user>`

  • :ref:`Create Postgres tablespaces <Creating Postgres tablespaces>`

  • :ref:`Create Postgres databases <Creating Postgres databases>`

  • :ref:`Configure pglogical replication <pglogical configuration>`

  • :ref:`Configure .pgpass <Configuring .pgpass>`

You can use the postgres-config-final hook

to execute tasks after the post-startup Postgres configuration is complete (for example, to perform SQL queries to create objects or load data).

  • :ref:`Configure BDR <EDB Postgres Distributed configuration>`

You can use the post-deploy hook

to execute tasks after the deployment process is complete.