PostgreSQL Backups with Docker

Prerequisites

the project was generated with use_docker set to y ;

the stack is up and running: docker-compose -f local.yml up -d postgres .

• When running these commands in production, switch to production.yml

Creating a Backup

To create a backup, run::

text

`$ docker-compose -f local.yml exec postgres backup
`

Assuming your project's database is named my_project here is what you will see: ::

text

`Backing up the 'my_project' database...  SUCCESS: 
'my_project' database backup 'backup_2022_03_13T09_05_07.sql.gz' has been created and 
placed in '/backups'.
`

• Keep in mind that /backups is the postgres container directory that is mounted on the container. *

Viewing the Existing Backups

To list existing backups

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` $ docker-compose -f local.yml exec postgres backups
`

These are the sample contents of /backups : ::

text

` These are the backups you have got:
total 92.5K
-rw-r--r-- 1 root root 51.3K Mar 24 03:04 backup_2022_03_24T03_04_07.sql.gz
-rw-r--r-- 1 root root 41.2K Mar 14 02:04 backup_2022_03_14T02_04_07.sql.gz
`

Copying Backups Locally

If you want to copy backups from your postgres container locally, docker cp command_ will help you on that.

For example, given 9c5c3f055843 is the container ID copying all the backups over to a local directory:

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`$ docker cp 9c5c3f055843:/backups ./backups
`

With a single backup file copied to . that would be:

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`$ docker cp 5j7c3fD89s43:/backups/backup_2022_03_14T02_04_07.sql.gz.sql.gz .
`

You can also get the container ID using docker-compose -f local.yml ps -q postgres so if you want to automate your backups, you don't have to check the container ID manually every time. Here is the full command ::

text

`$ docker cp $(docker-compose -f local.yml ps -q postgres):/backups ./backups
`

Docker reference for this command.

Restoring from the Existing Backup

To restore from one of the backups you have already got (take the backup_2022_03_14T02_04_07.sql.gz for example)

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`$ docker-compose -f local.yml exec postgres restore backup_2022_03_14T02_04_07.sql.gz
`

Example output will be

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`Restoring the 'my_project' database from the    '/backups/backup_2022_03_14T02_04_07.sql.gz' backup...
INFO: Dropping the database...
INFO: Creating a new database...
INFO: Applying the backup to the new database...
SET
SET
SET
SET
SET
set_config
 --------

(1 row)

 SET
 # ...
 ALTER TABLE
SUCCESS: The 'my_project' database has been restored from the '/backups/backup_2022_03_14T02_04_07.sql.gz' backup.
`

Backup to Amazon S3

For uploading your backups to Amazon S3 you can use the aws cli container. There is an upload command for uploading the postgres /backups directory recursively and there is a download command for downloading a specific backup.

The default S3 environment variables are used.

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`$ docker-compose -f production.yml run --rm awscli upload
$ docker-compose -f production.yml run --rm awscli download backup_2022_03_14T02_04_07.sql.gz
`