GCP Snapshot Automation Scripts

Pre- and post-snapshot hooks for Google Cloud Platform (GCP) Compute Engine persistent disk snapshots, ensuring application- and filesystem-consistent backups.

Overview

Taking live disk snapshots without quiescing active databases and filesystems can cause data corruption upon restore. These scripts coordinate a synchronized freeze and thaw across the storage and service stack.

Architecture & Flow

1. gcloud-snapshots/pre.sh (Quiesce):
   • Locks MySQL / MariaDB tables (FLUSH TABLES WITH READ LOCK)
   • Gracefully stops LiteSpeed web server (lswsctrl graceful)
   • Closes active Elasticsearch index
   • Flushes write buffers (sync) and freezes the XFS filesystem (xfs_freeze -f /)
2. GCP Disk Snapshot: Snapshot captured in a clean, crash-consistent state.
3. gcloud-snapshots/post.sh (Thaw & Resume):
   • Unfreezes XFS filesystem (xfs_freeze -u /)
   • Starts LiteSpeed web server (lswsctrl start)
   • Releases database lock (UNLOCK TABLES)
   • Reopens Elasticsearch index

Setup

Configure these scripts as pre/post snapshot guest environment scripts in Google Cloud Compute Engine snapshot schedules.