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Backing Up

Backing up is the process of taking backups from your database via mysql-backup, and saving the backup file to a target. That target can be one of:

  • local file
  • SMB remote file
  • S3 bucket

Instructions and Examples for Backup Configuration Options

Database Names

By default, all databases in the database server are backed up, and the system databases named information_schema, performance_schema, sys and mysql are excluded. For example, if you set DB_NAMES_EXCLUDE=database1 db2 then these two databases will not be dumped.

Dumping just some databases

  • Environment variable: DB_NAMES=db1,db2,db3
  • CLI flag: --include=db1 --include=db2 --include=db3
  • Config file:
dump:
  include:
  - db1
  - db2
  - db3

Dumping all databases

  • Environment variable: DB_NAMES=
  • CLI flag: --include=
  • Config file:
dump:
  include:

Note that you do not need to set those explicitly; these are the defaults for those settings.

Dumping all databases except for one

  • Environment variable: DB_NAMES_EXCLUDE=notme,notyou
  • CLI flag: --exclude=notme,notyou
  • Config file:
dump:
  exclude:
  - notme
  - notyou

No Database Name

By default, the backup assumes you will restore the dump into a database with the same name as the one that you backed up. This means it will include the USE <database>; statement in the dump, so it will switch to the correct database when you restore the dump.

If you do not want the USE statement in the backup file, for example if you might want to restore the dump to a different database, you need to remove the USE <database>; statement from the dump. mysql-backup does this for you when you set:

  • Environment variable: NO_DATABASE_NAME=true.
  • CLI flag: --no-database-name=true
  • Config file:
dump:
  no-database-name: true

Remember that each database schema will be in its own file, so you can determine the original by looking at the filename.

Dump File

The backup file itself always is a compressed file the following format:

db_backup_YYYY-MM-DDTHH:mm:ssZ.<compression>

Where the date is RFC3339 date format, excluding the milliseconds portion.

  • YYYY = year in 4 digits
  • MM = month number from 01-12
  • DD = date for 01-31
  • HH = hour from 00-23
  • mm = minute from 00-59
  • ss = seconds from 00-59
  • T = literal character T, indicating the separation between date and time portions
  • Z = literal character Z, indicating that the time provided is UTC, or "Zulu"
  • compression = appropriate file ending for selected compression, one of: gz (gzip, default); bz2 (bzip2)

The time used is UTC time at the moment the dump begins.

Notes on format:

  • SMB does not allow for : in a filename (depending on server options), so they are replaced with the - character when writing to SMB.

  • Some shells do not handle a : in the filename gracefully. Although these usually are legitimate characters as far as the filesystem is concerned, your shell may not like it. To avoid this issue, you can set the "no-colons" options with the "safechars" configuration:

  • Environment variable: DB_DUMP_SAFECHARS=true

  • CLI flag: dump --safechars=true

  • Config file:

dump:
  safechars: true

Dump Target

You set where to put the dump file via configuration. The format is different between using environment variables and CLI flags, vs config file. The environment variable and CLI support only simple formats, i.e. a single URL for a target. For more advanced options, such as specific credentials and settings, use the config file.

Environment Variables and CLI

For example, to set it to a local directory named /db:

  • Environment variable: DB_DUMP_TARGET=/db
  • CLI flag: dump --target=/db

It must be a directory.

The value of the environment variable or CLI target can be one of three formats, depending on the type of target:

  • Local: If it starts with a / character or file:/// url, it will dump to a local path. If in a container, you should have it volume-mounted.
  • SMB: If it is a URL of the format smb://hostname/share/path/ then it will connect via SMB.
  • S3: If it is a URL of the format s3://bucketname.fqdn.com/path then it will connect via using the S3 protocol.

In addition, you can send to multiple targets by separating them with a whitespace for the environment variable, or native multiple options for other configuration options. For example, to send to a local directory and an SMB share:

  • Environment variable: DB_DUMP_TARGET="/db smb://hostname/share/path/"
  • CLI flag: dump --target=/db --target=smb://hostname/share/path/"
Local File

If the target starts with / or is a file:/// then it is assumed to be a directory. The file will be written to that directory.

The target must be to a directory, wherein the dump file will be saved, using the naming convention listed above.

  • Environment variable: DB_DUMP_TARGET=/db
  • CLI flag: dump --target=/db

If running in a container, you will need to ensure that the directory target is mounted. See container considerations.

SMB

If you use a URL that begins with smb://, for example smb://host/share/path, the dump file will be saved to an SMB server.

The full URL must be to a directory on the SMB server, wherein the dump file will be saved, using the naming convention listed above.

If you need login credentials, you can either use the URL format smb://user:pass@host/share/path, or you can use the SMB user and password options:

  • Environment variable: SMB_USER=user SMB_PASS=pass
  • CLI flag: --smb-user=user --smb-pass=pass

The explicit credentials in SMB_USER and SMB_PASS override user and pass values in the URL.

Note that for smb, if the username includes a domain, e.g. your user is mydom\myuser, then you should use the smb convention of replacing the '' with a ';'. In other words smb://mydom;myuser:pass@host/share/path

S3

If you use a URL that begins with s3://, for example s3://bucket/path, the dump file will be saved to the S3 bucket.

The full URL must be to a directory in the S3 bucket, wherein the dump file will be saved, using the naming convention listed above.

Note that for s3, you'll need to specify your AWS credentials and default AWS region via the appropriate settings.

For example, to set the AWS credentials:

  • Environment variable: AWS_ACCESS_KEY_ID=accesskey AWS_SECRET_ACCESS_KEY=secretkey AWS_REGION=us-east-1
  • CLI flag: --aws-access-key-id=accesskey --aws-secret-access-key=secretkey --aws-region=us-east-1

If you are using an s3-interoperable storage system like DigitalOcean you will need to set the AWS endpoint URL via the AWS endpoint URL setting.

For example, to use Digital Ocean, whose endpoint URL is ${REGION_NAME}.digitaloceanspaces.com:

  • Environment variable: AWS_ENDPOINT_URL=https://nyc3.digitaloceanspaces.com
  • CLI flag: --aws-endpoint-url=https://nyc3.digitaloceanspaces.com

Note that if you have multiple S3-compatible backup targets, each with its own set of credentials, region or endpoint, then you must use the config file. There is no way to distinguish between multiple sets of credentials via the environment variables or CLI flags, while the config file provides credentials for each target.

Configuration File

The configuration file is the most flexible way to configure the dump target. It allows you to specify multiple targets, along with credentials and options for each target. It also keeps credentials in a file, rather than in the shell history, and makes the command-line much simpler. Finally, of course, it allows you to track the history of the file.

In the configuration file, a main section lists all potential targets, along with their configuration.

targets:
  s3:
    type: s3
    url: s3://bucket.us-west.amazonaws.com/databackup
    region: us-west-1
    endpoint: https://s3.us-west-1.amazonaws.com
    credentials:
      access-key-id: access_key_id
      secret-access-key: secret_access_key
  file:
    type: file
    url: file:///tmp/databackup
  otherfile:
    type: file
    url: /tmp/databackup
  smbshare:
    type: smb
    url: smb://cifshost:2125/databackup
    credentials:
      domain: mydomain
      username: user
      password: password

Notice that each section is a key-value, where the key is the unique name for that target. It need not have any meaning, other than a useful reference to you. For example, one of our targets is named s3, while another is named otherfile.

The uniquely named targets allow you to have separate configuration and credentials. For example, you can have two distinct s3-compatible targets, each with its own endpoint, region, and credentials. That would not be possible with the CLI or environment variables, as they rely on the common AWS_ACCESS_KEY_ID environment variable, or its CLI flag equivalent.

Once the targets are defined, you can reference them in the dump section by their unique keyed name:

dump:
  targets:
  - s3
  - file
  - otherfile
Custom backup file name

There may be use-cases where you need to modify the name and path of the backup file when it gets uploaded to the dump target.

For example, if you need the filename not to be <root-dir>/db_backup_<timestamp>.gz but perhaps <root-dir>/<year>/<month>/<day>/mybackup_<timestamp>.gz.

To do that, configure the environment variable DB_DUMP_FILENAME_PATTERN or its CLI flag or config file equivalent.

The content is a string that contains a pattern to be used for the filename. The pattern can contain the following placeholders:

  • {{.now}} - date of the backup, as included in {{.dumpfile}} and given by date -u +"%Y-%m-%dT%H:%M:%SZ"
  • {{.year}}
  • {{.month}}
  • {{.day}}
  • {{.hour}}
  • {{.minute}}
  • {{.second}}
  • {{.compression}} - appropriate extension for the compression used, for example, .gz or .bz2

Example run:

mysql-backup dump --source-filename-pattern="db-plus-wordpress_{{.now}}.gz"

If the execution time was 20180930151304, then the file will be named plus-wordpress_20180930151304.gz.

Backup pre and post processing

mysql-backup is capable of running arbitrary scripts for pre-backup and post-backup (but pre-upload) processing. This is useful if you need to include some files along with the database dump, for example, to backup a WordPress install.

In order to execute those scripts, you deposit them in appropriate dedicated directories and inform mysql-backup about the directories. Any file ending in .sh in the directory will be executed.

  • When using the binary, set the directories via the environment variable DB_DUMP_PRE_BACKUP_SCRIPTS or DB_DUMP_POST_BACKUP_SCRIPTS, or their CLI flag or config file equivalents.
  • When using the mysql-backup container, these are automatically set to the directories /scripts.d/pre-backup/ and /scripts.d/post-backup/, inside the container respectively. It is up to you to mount them.

Example run binary:

mysql-backup dump --pre-backup-scripts=/path/to/pre-backup/scripts --post-backup-scripts=/path/to/post-backup/scripts

Example run container:

docker run -d --restart=always -e DB_USER=user123 -e DB_PASS=pass123 -e DB_DUMP_FREQUENCY=60 \
  -e DB_DUMP_BEGIN=2330 -e DB_DUMP_TARGET=/db -e DB_SERVER=my-db-container:db \
  -v /path/to/pre-backup/scripts:/scripts.d/pre-backup \
  -v /path/to/post-backup/scripts:/scripts.d/post-backup \
  -v /local/file/path:/db \
  databack/mysql-backup

Or, if you prefer docker compose:

version: '2.1'
services:
  backup:
    image: databack/mysql-backup
    restart: always
    volumes:
     - /local/file/path:/db
     - /path/to/pre-backup/scripts:/scripts.d/pre-backup
     - /path/to/post-backup/scripts:/scripts.d/post-backup
    env:
     - DB_DUMP_TARGET=/db
     - DB_USER=user123
     - DB_PASS=pass123
     - DB_DUMP_FREQUENCY=60
     - DB_DUMP_BEGIN=2330
     - DB_SERVER=mysql_db
    command: dump
  mysql_db:
    image: mysql
    ....

The following environment variables are available:

  • DUMPFILE: full path in the container to the dump output file, and the file that will be uploaded to the target
  • NOW: date of the backup, as included in DUMPFILE and given by date -u +"%Y-%m-%dT%H:%M:%SZ"
  • DUMPDIR: path to the destination directory so for example you can copy a new tarball including some other files along with the sql dump.
  • DEBUG: To enable debug mode in post-backup scripts.

In addition, all of the environment variables set for the container will be available to the script.

For example, the following script will append data to the backup file after the dump is done:

#!/bin/bash
# Append data from /path/to/extra/files to the backup file after the dump is done.
if [[ -n "$DEBUG" ]]; then
  set -x
fi

if [ -e ${DUMPFILE} ];
then
  mv ${DUMPFILE} ${DUMPFILE}.tmp
  tar -zcvf /tmp/extra-files.tgz /path/to/extra/files
  cat ${DUMPFILE}.tmp /tmp/extra-files.tgz > ${DUMPFILE}
else
  echo "ERROR: Backup file ${DUMPFILE} does not exist!"
fi

Important: For post-processing, remember that at the end of the script, the dump file must be in the location specified by the DUMPFILE variable. If you move it, you must move it back.

Encrypting the Backup

Post-processing gives you options to encrypt the backup using openssl or any other tools. You will need to have it available on your system. When running in the mysql-backup container, the openssl binary is available to the processing scripts.

The sample examples/encrypt.sh provides a sample post-processing script that you can use to encrypt your backup with AES256.