Alpine PostgreSQL Backups

This is a minimalistic Docker container based on Alpine Linux with pghoard backup utility. It can be deployed to your cluster once and will manage backups for all configured PostgreSQL sites.

Container can be started either in backup or restoration mode, which is set by PGHOARD_RESTORE_SITE environment variable. If it's set to a valid host name from PG_HOSTS list, it will restore database to the latest available basebackup.

Installation

Image is available in nebo15/alpine-postgre-backup Docker Hub repo.

Environment variables

VAR_NAME	Default Value	Description
PGHOARD_ACTIVE_BACKUP_MODE	not set	Can be either pg_receivexlog or archive_command. If set to pg_receivexlog, pghoard will start up a pg_receivexlog process to be run against the database server. If archive_command is set, we rely on the user setting the correct archive_command in postgresql.conf. You can also set this to the experimental walreceiver mode whereby pghoard will start communicating directly with PostgreSQL through the replication protocol. (Note requires an unreleased version of psycopg2 library).
PGHOARD_BASEBACKUP_COUNT	2	How many basebackups should be kept around for restoration purposes. The more there are the more diskspace will be used.
PGHOARD_BASEBACKUP_INTERVAL_HOURS	24	How often to take a new basebackup of a cluster. The shorter the interval, the faster your recovery will be, but the more CPU/IO usage is required from the servers it takes the basebackup from. If set to a null value basebackups are not automatically taken at all.
PG_HOSTS	not set	List of PostgreSQL connections URLs separated by ;, eg: postgres://pghoard:secretpassword@host:5432/dbname;postgres://pghoard:secretpassword@other_host:5432/dbname. For each connection new pghoard backup site will be created.
PGHOARD_STATSD_ADDRESS	not set	Address or host on which StatsD server accepts metrics. StatsD collection will be disabled if this variable is not set.
PGHOARD_STATSD_PORT	8125	Port on which StatsD server accepts metrics.
PGHOARD_STATSD_FORMAT	datadog	Protocol that is supported by StatsD server: datadog or telegraf.
PGHOARD_LOG_LEVEL	INFO	Determines log level of pghoard.
PGHOARD_STORAGE_TYPE	not set	Where to store backups? Supported values: local, google, s3, azure, swift.

For restoration:

VAR_NAME	Default Value	Description
PGHOARD_RESTORE_SITE	not set	Host name of a backed-up database.
PGHOARD_ENCRYPTION_PRIVATE_KEY	not set	Private key to decrypt your backups. Optional.

Encrypt your backups:

VAR_NAME	Default Value	Description
PGHOARD_ENCRYPTION_KEY_ID	not set	Name of encryption key.
PGHOARD_ENCRYPTION_PUBLIC_KEY	not set	Public key to encrypt your backups.

Local storage

VAR_NAME	Default Value	Description
PGHOARD_DIRECTORY	not set

Amazon S3 storage

VAR_NAME	Default Value	Description
AWS_ACCESS_KEY_ID	not set
AWS_SECRET_ACCESS_KEY	not set
AWS_DEFAULT_REGION	not set
AWS_HOST	not set	Not required.
AWS_PORT	not set	Not required.
AWS_IS_SECURE	not set	Not required.
AWS_BUCKETNAME	not set

Google Cloud Storage

VAR_NAME	Default Value	Description
GCS_PROJECT_ID	not set	ID of a GCS project.
GCS_BUCKET_NAME	not set	Bucket name.
GCS_CREDENTIAL_FILE	not set	Path to the JSON credentials file. Generated in IAM -> Service Accounts.

OpenStack Swift storage

VAR_NAME	Default Value	Description
OS_USERNAME	not set
OS_PASSWORD	not set
OS_AUTH_URL	not set
OS_CONTAINER_NAME	not set
OS_REGION_NAME	not set	Not required.
OS_TENANT_NAME	not set

StatsD

If PGHOARD_STATSD_ADDRESS environment variable is set, this container will send meaningful metrics about backups:

• pghoard.compressed_size_ratio - (gauge) backups compression ratio.
• pghoard.last_upload_age - (gauge) number of seconds since last upload to the storage.
• pghoard.total_upload_size - (gauge) total upload volume.
• pghoard.upload_size - (rate) size of uploaded backup.
• pghoard.xlogs_since_basebackup - (gauge) number of XLogs since last basebackup.

License

See LICENSE.md.