# Backup and restore a Docker volume on Mac OS X

This is a rough draft for backing up and restoring data contained in a Docker volume. I
can't say that this is a "best practice". For my limited testing at the moment, it seems
sufficient.

## Example `docker-compose.yml`

```yml
version: '3'
services:
   db:
      image: mysql:5.7
      environment:
         MYSQL_ROOT_PASSWORD: secret
         MYSQL_DATABASE: tacos
         MYSQL_USER: tacos
         MYSQL_PASSWORD: secret
      volumes:
         - databasedata:/var/lib/mysql
volumes:
   databasedata:
      driver: 'local'
```

To start:

```
docker-compose up
```


## Login and interact with MySQL

From the host machine, where `DEADBEEF0123` is the ID of the running container.

```
docker exec -it DEADBEEF0123 bash
```

In the container:

```
mysql -u tacos -p
```


## Backup MySQL

From the host machine:

```
CONTAINER='DEADBEEF0123'
DIR_TO_BACKUP='/var/lib/mysql'
BACKUP_NAME='backup.tar'
docker run --rm --volumes-from "${CONTAINER}" -v $(pwd):/backup alpine:3.8 tar cvf "/backup/${BACKUP_NAME}" "${DIR_TO_BACKUP}"
```


## Restore MySQL

From the host machine:

```
CONTAINER='DEADBEEF0123'
BACKUP_NAME='backup.tar'
docker run --rm --volumes-from "${CONTAINER}" -v $(pwd):/backup alpine:3.8 tar xvf "/backup/${BACKUP_NAME}"
```