GitHub Enterprise Backup Utilities

This repository includes backup and recovery utilities for GitHub Enterprise.

• Features
• Requirements
  • Backup host requirements
  • Storage requirements
  • GitHub Enterprise version requirements
• Getting started
• Using the backup and restore commands
• Scheduling backups
• Backup snapshot file structure
• Support

Features

The backup utilities implement a number of advanced capabilities for backup hosts, built on top of the backup and restore features already included in GitHub Enterprise.

• Complete GitHub Enterprise backup and recovery system via two simple utilities:
  ghe-backup and ghe-restore.
• Online backups. The GitHub appliance need not be put in maintenance mode for the duration of the backup run.
• Incremental backup of Git repository data. Only changes since the last snapshot are transferred, leading to faster backup runs and lower network bandwidth and machine utilization.
• Efficient snapshot storage. Only data added since the previous snapshot consumes new space on the backup host.
• Multiple backup snapshots with configurable retention periods.
• Backup commands run under the lowest CPU/IO priority on the GitHub appliance, reducing performance impact while backups are in progress.
• Runs under most Linux/Unix environments.
• MIT licensed, open source software maintained by GitHub, Inc.

Requirements

The backup utilities should be run on a host dedicated to long-term permanent storage and must have network connectivity with the GitHub Enterprise appliance.

Backup host requirements

Backup host software requirements are modest: Linux or other modern Unix operating system with rsync v2.6.4 or newer.

The backup host must be able to establish network connections outbound to the GitHub appliance over SSH (port 22).

Storage requirements

Storage requirements vary based on current Git repository disk usage and growth patterns of the GitHub appliance. We recommend allocating at least 5x the amount of storage allocated to the primary GitHub appliance for historical snapshots and growth over time.

GitHub Enterprise version requirements

For online and incremental backup support, the GitHub Enterprise instance must be running version 11.10.342 or above.

Earlier versions are supported, but online and incremental backups are not supported. We strongly recommend upgrading to the latest release if you're running a version prior to 11.10.342. Visit enterprise.github.com to download the most recent GitHub Enterprise version.

Getting started

1. Download the latest release version and extract or clone the repository using Git:

   git clone -b stable https://github.com/github/backup-utils.git

2. Copy the backup.config-example file to backup.config and modify as necessary. The GHE_HOSTNAME value must be set to the GitHub Enterprise host name. Additional options are available and documented in the configuration file but none are required for basic backup functionality.

3. Add the backup host's SSH key to the GitHub appliance as an Authorized SSH key. See Adding an SSH key for shell access for instructions.

4. Run bin/ghe-host-check to verify SSH connectivity with the GitHub appliance.

5. Run bin/ghe-backup to perform an initial full backup.

Using the backup and restore commands

After the initial backup, use the following commands:

• The ghe-backup command creates incremental snapshots of repository data, along with full snapshots of all other pertinent data stores.
• The ghe-restore command restores snapshots to the same or separate GitHub Enterprise appliance. If you are restoring to a separate appliance, follow the steps in Migrating GitHub Enterprise.

Example backup and restore usage

The following assumes that GHE_HOSTNAME is set to "github.example.com" in backup.config.

Creating a backup snapshot:

$ ghe-backup
Starting backup of github.example.com in snapshot 20140727T224148
Connect github.example.com OK (v11.10.343)
Backing up GitHub settings ...
Backing up SSH authorized keys ...
Backing up SSH host keys ...
Backing up MySQL database ...
Backing up Redis database ...
Backing up Git repositories ...
Backing up GitHub Pages ...
Backing up Elasticsearch indices ...
Completed backup of github.example.com in snapshot 20140727T224148 at 23:01:58

Restoring from last successful snapshot to a newly provisioned GitHub Enterprise appliance at IP "5.5.5.5":

$ ghe-restore 5.5.5.5
Starting rsync restore of 5.5.5.5 from snapshot 20140727T224148
Connect 5.5.5.5 OK (v11.10.343)
Enabling maintenance mode on 5.5.5.5 ...
Restoring Git repositories ...
Restoring GitHub Pages ...
Restoring MySQL database ...
Restoring Redis database ...
Restoring SSH authorized keys ...
Restoring Elasticsearch indices ...
Restoring SSH host keys ...
Completed restore of 5.5.5.5 from snapshot 20140817T174152
Visit https://5.5.5.5/setup/settings to configure the recovered appliance.

Any backup can be applied using the -s argument and the datestamp-named directory from the backup location.

The ghe-backup and ghe-restore commands also have a verbose output mode (-v) that lists files as they're being transferred. It's often useful to enable when output is logged to a file.

Scheduling backups

Regular backups should be scheduled using cron(8) or similar command scheduling service on the backup host. The backup frequency will dictate the worst case recovery point objective (RPO) in your backup plan. We recommend the following:

• Hourly backups for GitHub Enterprise versions 11.10.342 or greater (due to improved online and incremental backup support)
• Daily backups for versions prior to 11.10.342.

Note: the time required to do full offline backups of large datasets under GitHub Enterprise versions prior to 11.10.342 may prohibit the use of daily backups. We strongly recommend upgrading to 11.10.342 or greater in that case.

Example scheduling usage

The following examples assume the backup utilities are installed under /opt/backup-utils. The crontab entry should be made under the same user that manual backup/recovery commands will be issued under and must have write access to the configured GHE_DATA_DIR directory.

Note that the GHE_NUM_SNAPSHOTS option in backup.config should be tuned based on the frequency of backups. The ten most recent snapshots are retained by default. The number should be adjusted based on backup frequency and available storage.

To schedule hourly backup snapshots with verbose informational output written to a log file and errors generating an email:

[email protected]

0 * * * * /opt/backup-utils/bin/ghe-backup -v 1>>/opt/backup-utils/backup.log

To schedule nightly backup snapshots instead, use:

[email protected]

0 0 * * * /opt/backup-utils/bin/ghe-backup -v 1>>/opt/backup-utils/backup.log

Backup snapshot file structure

Backup snapshots are stored in rotating increment directories named after the date and time the snapshot was taken. Each snapshot directory contains a full backup snapshot of all relevant data stores. Repository, Search, and Pages data is stored efficiently via hard links.

The following example shows a snapshot file hierarchy for hourly frequency. There are five snapshot directories, with the current symlink pointing to the most recent successful snapshot:

./data
   |- 20140724T010000
   |- 20140725T010000
   |- 20140726T010000
   |- 20140727T010000
   |- 20140728T010000
      |- authorized-keys.json
      |- elasticsearch/
      |- enterprise.ghl
      |- mysql.sql.gz
      |- pages/
      |- redis.rdb
      |- repositories/
      |- settings.json
      |- ssh-host-keys.tar
      |- strategy
      |- version
   |- current -> 20140727T010000

Note: the GHE_DATA_DIR variable set in backup.config can be used to change the disk location where snapshots are written.

Support

If you find a bug or would like to request a feature in backup-utils, please open an issue or pull request on this repository. If you have a question related to your specific GitHub Enterprise setup or would like assistance with backup site setup or recovery, please contact our Enterprise support team instead.