init_server

The init_server role performs initial server preparation for pgEdge cluster deployments. It installs required system packages, configures system settings, creates necessary users, and sets up SSH keys for inter-node communication.

This role performs the following tasks on inventory hosts:

• Install required system packages for Ansible and cluster operations.
• Configure SELinux settings according to deployment needs.
• Establish core dump handling for debugging purposes.
• Manage /etc/hosts entries for all cluster nodes.
• Disable RemoveIPC in systemd-logind to prevent shared memory segments from being removed when a user session ends.
• Create the postgres OS user and generate an SSH key pair for backup operations.
• Create a backup OS user on dedicated backup nodes.

Role Dependencies

This role requires the following role for normal operation:

• role_config provides shared configuration variables.

When to Use

Execute this role on all hosts in your cluster as the first step of any deployment. Always run init_server before any other roles; it establishes the foundation for the entire deployment.

In the following example, the playbook runs init_server on all hosts:

- hosts: all
  collections:
    - pgedge.platform
  roles:
    - init_server

Configuration

This role uses the following parameters from the inventory file:

See the Configuration Reference for a complete list of available parameters.

How It Works

This role operates in several phases to prepare servers for cluster deployment.

Package Installation

This role installs required system packages on all target hosts. The following common packages apply to all systems:

• acl provides access control lists for Ansible temporary files.
• jq provides JSON processing for status checks.
• nano provides a text editor for configuration management.
• less provides a pager utility for viewing output.
• rsync provides file synchronization for backup operations.
• python3-cryptography provides cryptography support for Ansible.

On RHEL-based systems, this role also installs kernel-modules-extra to provide additional kernel modules for core dumps. On Debian-based systems, this role installs systemd-coredump for core dump management.

SELinux Configuration

When you enable disable_selinux, this role modifies the SELinux configuration file, sets enforcement to disabled, and reboots the system to apply the change. The role only reboots when the SELinux state requires a change.

Core Dump Configuration

When you enable debug_pgedge, this role configures systemd-coredump settings, sets appropriate storage limits, and configures kernel parameters to allow unlimited core dump sizes.

RemoveIPC

This role disables the RemoveIPC setting in systemd-logind.conf. This prevents systemd from removing shared memory segments when a user session ends, which can disrupt running Postgres instances. The logind service restarts only if the setting was changed.

Host File Management

When you enable manage_host_file, this role gathers facts about all hosts in the cluster, maps hostnames to IP addresses, and adds entries to /etc/hosts on every node so all nodes can resolve each other by hostname.

User Creation

This role creates the postgres OS user and generates an ed25519 SSH key pair. On dedicated backup nodes, the role also creates the backup OS user with the name specified in backup_repo_user.

Usage Examples

In the following example, the playbook initializes all hosts with defaults:

- hosts: all
  collections:
    - pgedge.platform
  roles:
    - init_server

In the following example, the playbook disables optional features:

- hosts: all
  collections:
    - pgedge.platform
  roles:
    - role: init_server
      vars:
        debug_pgedge: false
        manage_host_file: false
        disable_selinux: false

Artifacts

During execution, this role generates and modifies the following files on inventory hosts:

Platform-Specific Behavior

On Debian-based systems, this role uses apt for package installation and installs systemd-coredump for core dump management. On RHEL-based systems, this role uses dnf, installs kernel-modules-extra for core dumps, and manages SELinux configuration when enabled.

Idempotency

This role is idempotent and safe to re-run on inventory hosts. The role skips SSH key generation and user creation when the targets already exist. The role may update /etc/hosts when you add new nodes to the cluster and reboots only when SELinux state requires a change.