diff --git a/README.md b/README.md index 185184a..7e387ae 100644 --- a/README.md +++ b/README.md @@ -2,114 +2,42 @@ Backup Docker volumes locally or to any S3 compatible storage. -The [offen/docker-volume-backup](https://hub.docker.com/r/offen/docker-volume-backup) Docker image can be used as a lightweight (below 15MB) sidecar container to an existing Docker setup. It handles __recurring or one-off backups of Docker volumes__ to a __local directory__ or __any S3 compatible storage__ (or both), and __rotates away old backups__ if configured. It also supports __encrypting your backups using GPG__. +The [offen/docker-volume-backup](https://hub.docker.com/r/offen/docker-volume-backup) Docker image can be used as a lightweight (below 15MB) sidecar container to an existing Docker setup. +It handles __recurring or one-off backups of Docker volumes__ to a __local directory__ or __any S3 compatible storage__ (or both), and __rotates away old backups__ if configured. It also supports __encrypting your backups using GPG__. -## Configuration + -Backup targets, schedule and retention are configured in environment variables: +- [Quickstart](#quickstart) +- [Configuration reference](#configuration-reference) +- [How to](#how-to) + - [Stopping containers during backup](#stopping-containers-during-backup) + - [Automatically pruning old backups](#automatically-pruning-old-backups) + - [Encrypting your backup using GPG](#encrypting-your-backup-using-gpg) + - [Restoring a volume from a backup](#restoring-a-volume-from-a-backup) + - [Using with Docker Swarm](#using-with-docker-swarm) + - [Manually triggering a backup](#manually-triggering-a-backup) +- [Recipes](#recipes) + - [Backing up to AWS S3](#backing-up-to-aws-s3) + - [Backing up to MinIO](#backing-up-to-minio) + - [Backing up locally](#backing-up-locally) + - [Backing up to AWS S3 as well as locally](#backing-up-to-aws-s3-as-well-as-locally) + - [Running on a custom cron schedule](#running-on-a-custom-cron-schedule) + - [Rotating away backups that are older than 7 days](#rotating-away-backups-that-are-older-than-7-days) + - [Encrypting your backups using GPG](#encrypting-your-backups-using-gpg) + - [Running multiple instances in the same setup](#running-multiple-instances-in-the-same-setup) +- [Differences to `futurice/docker-volume-backup`](#differences-to-futuricedocker-volume-backup) -```ini -########### BACKUP SCHEDULE + -# Backups run on the given cron schedule and use the filename defined in the -# template expression. +--- -BACKUP_CRON_EXPRESSION="0 2 * * *" -# Format verbs will be replaced as in the `date` command. Omitting them -# will result in the same filename for every backup run, which means previous -# versions will be overwritten. -BACKUP_FILENAME="backup-%Y-%m-%dT%H-%M-%S.tar.gz" +Code and documentation for `v1` versions are found on [this branch][v1-branch]. -########### BACKUP STORAGE +[v1-branch]: https://github.com/offen/docker-volume-backup/tree/v1 -# Define credentials for authenticating against the backup storage and a bucket -# name. Although all of these values are `AWS`-prefixed, the setup can be used -# with any S3 compatible storage. +## Quickstart -AWS_ACCESS_KEY_ID="" -AWS_SECRET_ACCESS_KEY="" -AWS_S3_BUCKET_NAME="" - -# This is the FQDN of your storage server, e.g. `storage.example.com`. -# Do not set this when working against AWS S3. If you need to set a -# specific protocol, you will need to use the option below. - -# AWS_ENDPOINT="" - -# The protocol to be used when communicating with your storage server. -# Defaults to "https". You can set this to "http" when communicating with -# a different Docker container on the same host for example. - -# AWS_ENDPOINT_PROTO="https" - -# Setting this variable to any value will disable verification of -# SSL certificates. You shouldn't use this unless you use self-signed -# certificates for your remote storage backend. - -# AWS_ENDPOINT_INSECURE="true" - -# In addition to backing up you can also store backups locally. Pass in -# a local path to store your backups here if needed. You likely want to -# mount a local folder or Docker volume into that location when running -# the container. Local paths can also be subject to pruning of old -# backups as defined below. - -# BACKUP_ARCHIVE="/archive" - -########### BACKUP PRUNING - -# **IMPORTANT, PLEASE READ THIS BEFORE USING THIS FEATURE**: -# The mechanism used for pruning backups is not very sophisticated -# and applies its rules to **all files in the target directory** by default, -# which means that if you are storing your backups next to other files, -# these might become subject to deletion too. When using this option -# make sure the backup files are stored in a directory used exclusively -# for storing them or to configure BACKUP_PRUNING_PREFIX to limit -# removal to certain files. - -# Define this value to enable automatic pruning of old backups. The value -# declares the number of days for which a backup is kept. - -# BACKUP_RETENTION_DAYS="7" - -# In case the duration a backup takes fluctuates noticeably in your setup -# you can adjust this setting to make sure there are no race conditions -# between the backup finishing and the rotation not deleting backups that -# sit on the very edge of the time window. Set this value to a duration -# that is expected to be bigger than the maximum difference of backups. -# Valid values have a suffix of (s)econds, (m)inutes or (h)ours. - -# BACKUP_PRUNING_LEEWAY="1m" - -# In case your target bucket or directory contains other files than the ones -# managed by this container, you can limit the scope of rotation by setting -# a prefix value. This would usually be the non-parametrized part of your -# BACKUP_FILENAME. E.g. if BACKUP_FILENAME is `db-backup-%Y-%m-%dT%H-%M-%S.tar.gz`, -# you can set BACKUP_PRUNING_PREFIX to `db-backup-` and make sure -# unrelated files are not affected. - -# BACKUP_PRUNING_PREFIX="backup-" - -########### BACKUP ENCRYPTION - -# Backups can be encrypted using gpg in case a passphrase is given - -# GPG_PASSPHRASE="" - -########### STOPPING CONTAINERS DURING BACKUP - -# Containers can be stopped by applying a -# `docker-volume-backup.stop-during-backup` label. By default, all containers -# that are labeled with `true` will be stopped. If you need more fine grained -# control (e.g. when running multiple containers based on this image), you can -# override this default by specifying a different value here. - -# BACKUP_STOP_CONTAINER_LABEL="service1" -``` - -## Example in a docker-compose setup - -Most likely, you will use this image as a sidecar container in an existing docker-compose setup like this: +Add a `backup` service to your compose setup and mount the volumes you would like to see backed up: ```yml version: '3' @@ -129,24 +57,232 @@ services: backup: image: offen/docker-volume-backup:latest restart: always - env_file: ./backup.env + env_file: ./backup.env # see below for configuration reference volumes: + - data:/backup/my-app-backup:ro # Mounting the Docker socket allows the script to stop and restart # the container during backup. You can omit this if you don't want # to stop the container - /var/run/docker.sock:/var/run/docker.sock:ro - - data:/backup/my-app-backup:ro # If you mount a local directory or volume to `/archive` a local # copy of the backup will be stored there. You can override the - # location inside of the container by setting `BACKUP_ARCHIVE` - # - /path/to/local_backups:/archive + # location inside of the container by setting `BACKUP_ARCHIVE`. + # You can omit this if you do not want to keep local backups. + - /path/to/local_backups:/archive volumes: data: ``` -## Using with Docker Swarm +## Configuration reference -By default, Docker Swarm will restart stopped containers automatically, even when manually stopped. If you plan to have your containers / services stopped during backup, this means you need to apply the `on-failure` restart policy to your service's definitions. A restart policy of `always` is not compatible with this tool. +Backup targets, schedule and retention are configured in environment variables. +You can populate below template according to your requirements and use it as your `env_file`: + +```ini +########### BACKUP SCHEDULE + +# Backups run on the given cron schedule in `busybox` flavor. If no +# value is set, `@daily` will be used. If you do not want the cron +# to ever run, use `0 0 5 31 2 ?`. + +# BACKUP_CRON_EXPRESSION="0 2 * * *" + +# The name of the backup file including the `.tar.gz` extension. +# Format verbs will be replaced as in `strftime`. Omitting them +# will result in the same filename for every backup run, which means previous +# versions will be overwritten on subsequent runs. The default results +# in filenames like `backup-2021-08-29T04-00-00.tar.gz`. + +# BACKUP_FILENAME="backup-%Y-%m-%dT%H-%M-%S.tar.gz" + +########### BACKUP STORAGE + +# The name of the remote bucket that should be used for storing backups. If +# this is not set, no remote backups will be stored. + +# AWS_S3_BUCKET_NAME="backup-bucket" + +# Define credentials for authenticating against the backup storage and a bucket +# name. Although all of these keys are `AWS`-prefixed, the setup can be used +# with any S3 compatible storage. + +# AWS_ACCESS_KEY_ID="" +# AWS_SECRET_ACCESS_KEY="" + +# This is the FQDN of your storage server, e.g. `storage.example.com`. +# Do not set this when working against AWS S3 (the default value is +# `s3.amazonaws.com`). If you need to set a specific (non-https) protocol, you +# will need to use the option below. + +# AWS_ENDPOINT="storage.example.com" + +# The protocol to be used when communicating with your storage server. +# Defaults to "https". You can set this to "http" when communicating with +# a different Docker container on the same host for example. + +# AWS_ENDPOINT_PROTO="https" + +# Setting this variable to `true` will disable verification of +# SSL certificates. You shouldn't use this unless you use self-signed +# certificates for your remote storage backend. + +# AWS_ENDPOINT_INSECURE="true" + +# In addition to storing backups remotely, you can also keep local copies. +# Pass a container-local path to store your backups if needed. You also need to +# mount a local folder or Docker volume into that location (`/archive` +# by default) when running the container. In case the specified directory does +# not exist (nothing is mounted) in the container when the backup is running, +# local backups will be skipped. Local paths are also be subject to pruning of +# old backups as defined below. + +# BACKUP_ARCHIVE="/archive" + +########### BACKUP PRUNING + +# **IMPORTANT, PLEASE READ THIS BEFORE USING THIS FEATURE**: +# The mechanism used for pruning old backups is not very sophisticated +# and applies its rules to **all files in the target directory** by default, +# which means that if you are storing your backups next to other files, +# these might become subject to deletion too. When using this option +# make sure the backup files are stored in a directory used exclusively +# for such files, or to configure BACKUP_PRUNING_PREFIX to limit +# removal to certain files. + +# Define this value to enable automatic rotation of old backups. The value +# declares the number of days for which a backup is kept. + +# BACKUP_RETENTION_DAYS="7" + +# In case the duration a backup takes fluctuates noticeably in your setup +# you can adjust this setting to make sure there are no race conditions +# between the backup finishing and the rotation not deleting backups that +# sit on the edge of the time window. Set this value to a duration +# that is expected to be bigger than the maximum difference of backups. +# Valid values have a suffix of (s)econds, (m)inutes or (h)ours. By default, +# one minute is used. + +# BACKUP_PRUNING_LEEWAY="1m" + +# In case your target bucket or directory contains other files than the ones +# managed by this container, you can limit the scope of rotation by setting +# a prefix value. This would usually be the non-parametrized part of your +# BACKUP_FILENAME. E.g. if BACKUP_FILENAME is `db-backup-%Y-%m-%dT%H-%M-%S.tar.gz`, +# you can set BACKUP_PRUNING_PREFIX to `db-backup-` and make sure +# unrelated files are not affected by the rotation mechanism. + +# BACKUP_PRUNING_PREFIX="backup-" + +########### BACKUP ENCRYPTION + +# Backups can be encrypted using gpg in case a passphrase is given. + +# GPG_PASSPHRASE="" + +########### STOPPING CONTAINERS DURING BACKUP + +# Containers can be stopped by applying a +# `docker-volume-backup.stop-during-backup` label. By default, all containers +# that are labeled with `true` will be stopped. If you need more fine grained +# control (e.g. when running multiple containers based on this image), you can +# override this default by specifying a different value here. + +# BACKUP_STOP_CONTAINER_LABEL="service1" +``` + +## How to + +### Stopping containers during backup + +In many cases, it will be desirable to stop the services that are consuming the volume you want to backup in order to ensure data integrity. +This image can automatically stop and restart containers and services (in case you are running Docker in Swarm mode). +By default, any container that is labeled `docker-volume-backup.stop-during-backup=true` will be stopped before the backup is being taken and restarted once it has finished. + +In case you need more fine grained control about which containers should be stopped (e.g. when backing up multiple volumes on different schedules), you can set the `BACKUP_STOP_CONTAINER_LABEL` environment variable and then use the same value for labeling: + +```yml +version: '3' + +services: + app: + # definition for app ... + labels: + - docker-volume-backup.stop-during-backup=service1 + + backup: + image: offen/docker-volume-backup:latest + environment: + BACKUP_STOP_CONTAINER_LABEL: service1 + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Automatically pruning old backups + +When `BACKUP_RETENTION_DAYS` is configured, the image will check if there are any backups in the remote bucket or local archive that are older than the given retention value and rotate these backups away. + +Be aware that this mechanism looks at __all files in the target bucket or archive__, which means that other files that are older than the given deadline are deleted as well. In case you need to use a target that cannot be used exclusively for your backups, you can configure `BACKUP_PRUNING_PREFIX` to limit which files are considered eligible for deletion: + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz + BACKUP_PRUNING_PREFIX: backup- + BACKUP_RETENTION_DAYS: 7 + volumes: + - ${HOME}/backups:/archive + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Encrypting your backup using GPG + +The image supports encrypting backups using GPG out of the box. +In case a `GPG_PASSPHRASE` environment variable is set, the backup will be encrypted using the given key and saved as a `.gpg` file instead. + +Assuming you have `gpg` installed, you can decrypt such a backup using (your OS will prompt for the passphrase before decryption can happen): + +```console +gpg -o backup.tar.gz -d backup.tar.gz.gpg +``` + +### Restoring a volume from a backup + +In case you need to restore a volume from a backup, the most straight forward procedure to do so would be: + +- Stop the container(s) that are using the volume +- Untar the backup you want to restore + ```console + tar -C /tmp -xvf backup.tar.gz + ``` +- Using a temporary one-off container, mount the volume (the example assumes it's named `data`) and copy over the backup. Make sure you copy the correct path level (this depends on how you mount your volume into the backup container), you might need to strip some leading elements + ```console + docker run -d --name backup_restore -v data:/backup_restore alpine + docker cp /tmp/backup/data-backup backup_restore:/backup_restore + docker stop backup_restore + docker rm backup_restore + ``` +- Restart the container(s) that are using the volume + +Depending on your setup and the application(s) you are running, this might involve other steps to be taken still. + +### Using with Docker Swarm + +By default, Docker Swarm will restart stopped containers automatically, even when manually stopped. +If you plan to have your containers / services stopped during backup, this means you need to apply the `on-failure` restart policy to your service's definitions. +A restart policy of `always` is not compatible with this tool. --- @@ -162,7 +298,7 @@ services: memory: 25M ``` -## Manually triggering a backup +### Manually triggering a backup You can manually trigger a backup run outside of the defined cron schedule by executing the `backup` command inside the container: @@ -170,15 +306,207 @@ You can manually trigger a backup run outside of the defined cron schedule by ex docker exec backup ``` ---- +## Recipes + +This section lists configuration for some real-world use cases that you can mix and match according to your needs. + +### Backing up to AWS S3 + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Backing up to MinIO + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + AWS_ENDPOINT: minio.example.com + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: MINIOACCESSKEY + AWS_SECRET_ACCESS_KEY: MINIOSECRETKEY + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Backing up locally + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + - ${HOME}/backups:/archive + +volumes: + data: +``` + +### Backing up to AWS S3 as well as locally + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + - ${HOME}/backups:/archive + +volumes: + data: +``` + +### Running on a custom cron schedule + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + # take a backup on every hour + BACKUP_CRON_EXPRESSION: "0 * * * *" + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Rotating away backups that are older than 7 days + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + BACKUP_FILENAME: backup-%Y-%m-%dT%H-%M-%S.tar.gz + BACKUP_PRUNING_PREFIX: backup- + BACKUP_RETENTION_DAYS: 7 + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Encrypting your backups using GPG + +```yml +version: '3' + +services: + # ... define other services using the `data` volume here + backup: + image: offen/docker-volume-backup:latest + environment: + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + GPG_PASSPHRASE: somesecretstring + volumes: + - data:/backup/my-app-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data: +``` + +### Running multiple instances in the same setup + +```yml +version: '3' + +services: + # ... define other services using the `data_1` and `data_2` volumes here + backup_1: &backup_service + image: offen/docker-volume-backup:latest + environment: &backup_environment + BACKUP_CRON_EXPRESSION: "0 2 * * *" + AWS_BUCKET_NAME: backup-bucket + AWS_ACCESS_KEY_ID: AKIAIOSFODNN7EXAMPLE + AWS_SECRET_ACCESS_KEY: wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY + # Label the container using the `data_1` volume as `docker-volume-backup.stop-during-backup=service1` + BACKUP_STOP_CONTAINER_LABEL: service1 + volumes: + - data_1:/backup/data-1-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + backup_2: + <<: *backup_service + environment: + <<: *backup_environment + # Label the container using the `data_2` volume as `docker-volume-backup.stop-during-backup=service2` + BACKUP_CRON_EXPRESSION: "0 3 * * *" + BACKUP_STOP_CONTAINER_LABEL: service2 + volumes: + - data_2:/backup/data-2-backup:ro + - /var/run/docker.sock:/var/run/docker.sock:ro + +volumes: + data_1: + data_2: +``` ## Differences to `futurice/docker-volume-backup` This image is heavily inspired by the `futurice/docker-volume-backup`. We decided to publish this image as a simpler and more lightweight alternative because of the following requirements: -- The original image is based on `ubuntu` and additional tools, making it very heavy. This version is roughly 1/25 in compressed size (it's ~12MB). -- The original image uses a shell script, when this is written in Go, which makes it easier to extend and maintain (more verbose also). -- The original image proposed to handle backup rotation through AWS S3 lifecycle policies. This image adds the option to rotate away old backups through the same command so this functionality can also be offered for non-AWS storage backends like MinIO. Local copies of backups can also be pruned once they reach a certain age. +- The original image is based on `ubuntu` and requires additional tools, making it heavy. +This version is roughly 1/25 in compressed size (it's ~12MB). +- The original image uses a shell script, when this version is written in Go, which makes it easier to extend and maintain (more verbose too). +- The original image proposed to handle backup rotation through AWS S3 lifecycle policies. +This image adds the option to rotate away old backups through the same command so this functionality can also be offered for non-AWS storage backends like MinIO. +Local copies of backups can also be pruned once they reach a certain age. - InfluxDB specific functionality from the original image was removed. - `arm64` and `arm/v7` architectures are supported. - Docker in Swarm mode is supported. diff --git a/cmd/backup/main.go b/cmd/backup/main.go index 9fceffa..3291ed7 100644 --- a/cmd/backup/main.go +++ b/cmd/backup/main.go @@ -262,7 +262,7 @@ func (s *script) takeBackup() error { // encryptBackup encrypts the backup file using PGP and the configured passphrase. // In case no passphrase is given it returns early, leaving the backup file -// untouched. +// untouched. func (s *script) encryptBackup() error { if s.c.GpgPassphrase == "" { return nil @@ -311,14 +311,14 @@ func (s *script) copyBackup() error { if err != nil { return fmt.Errorf("copyBackup: error uploading backup to remote storage: %w", err) } - s.logger.Infof("Uploaded a copy of backup `%s` to bucket `%s`", s.file, s.c.AwsS3BucketName) + s.logger.Infof("Uploaded a copy of backup `%s` to bucket `%s`.", s.file, s.c.AwsS3BucketName) } if _, err := os.Stat(s.c.BackupArchive); !os.IsNotExist(err) { if err := copy(s.file, path.Join(s.c.BackupArchive, name)); err != nil { return fmt.Errorf("copyBackup: error copying file to local archive: %w", err) } - s.logger.Infof("Stored copy of backup `%s` in local archive `%s`", s.file, s.c.BackupArchive) + s.logger.Infof("Stored copy of backup `%s` in local archive `%s`.", s.file, s.c.BackupArchive) } return nil } @@ -345,7 +345,6 @@ func (s *script) pruneOldBackups() error { time.Sleep(s.c.BackupPruningLeeway) } - s.logger.Infof("Trying to prune backups older than %d day(s) now.", s.c.BackupRetentionDays) deadline := time.Now().AddDate(0, 0, -int(s.c.BackupRetentionDays)) if s.c.AwsS3BucketName != "" { @@ -468,6 +467,8 @@ func (s *script) pruneOldBackups() error { return nil } +// must exits the script run non-zero and prematurely in case the given error +// is non-nil. func (s *script) must(err error) { if err != nil { s.logger.Fatalf("Fatal error running backup: %s", err)