Backing Up

The service supports a custom plan for creating a consistent backup of the MongoDB replica set that is uploaded to a remote location. The backup plan launches an instance of Percona-Lab/mongodb_consistent_backup, creates a consistent backup of the replica set and uploads the backup to remote storage. Currently only AWS S3 is supported as an upload destination for backups via the plan named ‘backup-s3’. More upload methods are coming in the future!

There are two ways to configure backups: via the DC/OS Percona Server for MongoDB service configuration section ‘Backup restore’ in the DC/OS web interface, or the DC/OS CLI.

Hidden secondary member

The service supports the ability to launch a dedicated MongoDB hidden secondary replica set member to perform backups. Hidden secondary members cannot become Primary in a failover situation and are hidden to application drivers.

The use of a dedicated backup secondary guarantees that backups (a very resource-intensive process) do not impact database nodes used by the application, therefore we recommend enabling this when using backups. Enabling a hidden secondary will add a task named backup-0-mongod to the service. This node will inherit all settings from the other replica set nodes.

Starting a backup

Backups are started using the Percona Server for MongoDB CLI module’s backup command.

If the AWS Access Key, Secret Key, S3 Bucket Name and S3 Bucket Prefix are already defined in your service options the following will start a backup: shell $ dcos percona-server-mongodb backup run s3

If the AWS configuration/credentials are not defined in the service options or you would like to override them, define the options on the command line with the following: shell $ dcos percona-server-mongodb backup run s3 \ --access-key=XXXXXXXXXXXXXXXXXXX \ --secret-key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX \ --bucket-name=my-s3-bucket-name \ --bucket-prefix=/mongobackups \ --region=eu-central-1

A successful start of the backup will return the following:

```javascript
{
  "message": "Received cmd: start"
}
```

A task named mongodb-consistent-backup-0-backup will exist for the duration of the backup and upload. In this example, a backup will be uploaded to s3://my-s3-bucket-name/mongobackups/<DATE> containing several subdirectories.

Stopping a backup

To stop a running backup process:

```shell
$ dcos percona-server-mongodb backup stop s3
```

Troubleshooting a backup

To troubleshoot problems with backups, add the flag --backup-verbose to the backup command. Please report any issues with mongodb_consistent_backup to https://github.com/Percona-Lab/mongodb_consistent_backup/issues/new.

Restoring

You can restore a mongodump-based backup stored on Amazon S3 using the DC/OS GUI and CLI tool, including backups created by the service.

Using backups created by Percona Server for MongoDB

To restore an AWS S3-based backup that was created by the Percona Server for MongoDB backup feature, note that the AWS S3 URL must point to the dump directory for the desired replica set.

Example: To restore the replica set rs to a backup located at AWS S3 URL s3://my-s3-bucket-name-here/backup/20170618_1600, provide the following URL to the Percona Server for MongoDB Restore features: s3://my-s3-bucket-name-here/backup/20170618_1600/rs/dump.

Restoring at Replica Set initiation

The service supports running a restoration after the initiation of the MongoDB Replica Set. This is useful for migrations to the percona-server-mongodb service, cloning environments, and so on.

Steps:

In the DC/OS web interface, go to Catalog.
Find the percona-server-mongodb service.
Press Review & Run.
Go to the Backup Restore tab in the service configuration.
Set your AWS Access Key (accessKey) and Secret Key (secretKey) in the Aws s3 configuration section. This user must have access to read the backup.
Enter the AWS S3 URL to the dump backup directory that was output by mongodump into the s3Url field.
Check the restoreAfterInit field, to enable the restore once the replica set has been initiated.
Wait for the task restore-0-restore-s3 to reach the FINISHED state.

Restore using the DC/OS CLI

Start a manual restoration using the Percona Server for MongoDB CLI module’s restore command.

If the AWS Access Key and Secret Key are already defined in your service options, the following will start a restore:

```shell
dcos percona-server-mongodb restore run s3 s3://my-s3-bucket-name-here/backup/dump
```

If the AWS configuration/credentials are not defined in the service options or you would like to override them, define the options on the command line with the following:

```shell
dcos percona-server-mongodb restore run s3 \
    --access-key=XXXXXXXXXXXXXXXXXXX \
    --secret-key=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX \
    s3://my-s3-bucket-name-here/backup/dump
```

Stopping a restore process

To stop a running backup restore process:

```shell
dcos percona-server-mongodb restore stop s3
```

Troubleshooting a restore process

See the Logs page of the restore-0-restore-s3 task to troubleshoot the restore process.

Disaster Recovery

Creating a backup and recovery plan