Kubernetes StatefulSet

Provides a production-hardened instance of a Kubernetes StatefulSet with the following enhancements:

Automatic headless service creation
Standardized resource labels
Pod and container security hardening
Persistent volume creation and mounting with automatic integrations with the
PVC Autoresizer and Velero
Temporary directory mounting
ConfigMap and Secret mounting
Downward-API integrations
Service account configuration with default permissions
Integration with the Panfactum bin-packing scheduler
High-availability scheduling constraints
Readiness and liveness probe configurations
Automatic reloading via the Reloader
Vertical pod autoscaling
Pod disruption budget
Toleration switches for the various Panfactum node classes

Usage

Basics

This module follows the basic workload deployment patterns describe in this guide.

Horizontal Autoscaling

By default, this module does not have horizontal autoscaling built-in. If you wish to add horizontal autoscaling via the HPA (or similar controller), you should set ignore_replica_count to true to prevent this module from overriding the replica count set via horizontal autoscaling.

Persistence

One of the core use cases for a StatefulSet is the ability to persistent data across pod restarts through the use of Persistent Volume Claims (PVCs).

You can configure the StatefulSet’s PVCs via the volume_mounts input. This input is a map of names (arbitrary) to configuration values for each volume that should mounted to every pod in the StatefulSet.

The configuration values are as follows:

storage_class: The Storage Class to use for the volume. To learn more about the available storage class options, see our guide.
initial_size_gb: The size of the volume when it is first created.
increase_gb: How much the volume will grow every time it is autoscaled by the PVC autoresizer.
increase_threshold_percent: When free storage drops below this percent on the volume, the volume will be autoscaled.
size_limit_gb: The maximum size the volume is allowed to grow to.
mount_path: Absolute path inside each container that the volume is mounted to.
backups_enabled: Whether the PVC snapshots will be created when Velero backups are created (by default hourly).

PVCs can only be autoscaled every six hours (AWS limitation), so you must choose autoscaling parameters that ensure autoscaling can keep pace with your data growth rate.

You can configure the retention policy of the volumes through the volume_retention_policy input.