The postgres Unix user

This page documents how the postgres user and its home directory are configured.

There’s a separate page about how to create Postgres users in the database .

Shell configuration

TPA will install a .bashrc file and ensure that it’s also included by the .profile or .bash_profile files.

It will set a prompt that includes the username and hostname and working directory, and ensure that postgres_bin_dir in in the PATH , and set PGDATA to the location of postgres_data_dir .

You can optionally specify extra_bashrc_lines to append arbitrary lines to .bashrc . (Use the YAML multi-line string syntax >- to avoid having to worry about quoting and escaping shell metacharacters.)

cluster_vars:
  extra_bashrc_lines:
  - alias la=ls\ -la
  - >-
    export PATH="$PATH":/some/other/dir

It will edit sudoers to allow sudo systemctl start/stop/reload/restart/status postgres , and also change ulimits to allow unlimited core dumps and raise the file descriptor limits.

SSH keys

TPA will use ssh-keygen to generate and install an SSH keypair for the postgres user, and edit .ssh/authorized_keys so that the instances in the cluster can ssh to each other as postgres .

TLS certificates

By default, TPA will generate a private key and a self-signed TLS certificate for use within the cluster. If you create cluster_name.key and cluster_name.crt files within your cluster directory, it will use that key and certificate instead of generating one.

We strongly recommend either using the self-signed certificate (perfectly sufficient to ensure that traffic between clients and server is encrypted in transit) or making some more secure alternative arrangement to install the TLS private key and certificate on the instances (where the private key does not leave the instances). The details depend on your certificate-signing infrastructure.

Username

The postgres_user and postgres_group settings (both postgres by default) are used consistently everywhere. You can change them if you need to run Postgres as a different user for some reason.