Seeding a New Cluster with an Externally Created Backup - Amazon ElastiCache for Redis

Seeding a New Cluster with an Externally Created Backup

When you create a new Redis cluster, you can seed it with data from a Redis .rdb backup file. Seeding the cluster is useful if you currently manage a Redis instance outside of ElastiCache and want to populate your new ElastiCache for Redis cluster with your existing Redis data.

To seed a new Redis cluster from a Redis backup created within Amazon ElastiCache, see Restoring From a Backup with Optional Cluster Resizing.

When you use a Redis .rdb file to seed a new Redis cluster, you can do the following:

  • Upgrade from a nonpartitioned cluster to a Redis (cluster mode enabled) cluster running Redis version 3.2.4.

  • Specify a number of shards (called node groups in the API and CLI) in the new cluster. This number can be different from the number of shards in the cluster that was used to create the backup file.

  • Specify a different node type for the new cluster—larger or smaller than that used in the cluster that made the backup. If you scale to a smaller node type, be sure that the new node type has sufficient memory for your data and Redis overhead. For more information, see Ensuring That You Have Enough Memory to Create a Redis Snapshot.

  • Distribute your keys in the slots of the new Redis (cluster mode enabled) cluster differently than in the cluster that was used to create the backup file.

Note

You can't seed a Redis (cluster mode disabled) cluster from an .rdb file created from a Redis (cluster mode enabled) cluster.

Important
  • You must ensure that your Redis backup data doesn't exceed the resources of the node. For example, you can't upload an .rdb file with 5 GB of Redis data to a cache.m3.medium node that has 2.9 GB of memory.

    If the backup is too large, the resulting cluster has a status of restore-failed. If this happens, you must delete the cluster and start over.

    For a complete listing of node types and specifications, see Redis Node-Type Specific Parameters and Amazon ElastiCache Product Features and Details.

  • You can encrypt a Redis .rdb file with Amazon S3 server-side encryption (SSE-S3) only. For more information, see Protecting Data Using Server-Side Encryption.

Following, you can find topics that walk you through migrating your Redis cluster from outside ElastiCache for Redis to ElastiCache for Redis.

Step 1: Create a Redis Backup

To create the Redis backup to seed your ElastiCache for Redis instance

  1. Connect to your existing Redis instance.

  2. Run either the Redis BGSAVE or SAVE operation to create a backup. Note where your .rdb file is located.

    BGSAVE is asynchronous and does not block other clients while processing. For more information, see BGSAVE at the Redis website.

    SAVE is synchronous and blocks other processes until finished. For more information, see SAVE at the Redis website.

For additional information on creating a backup, see Redis Persistence at the Redis website.

Step 2: Create an Amazon S3 Bucket and Folder

When you have created the backup file, you need to upload it to a folder within an Amazon S3 bucket. To do that, you must first have an Amazon S3 bucket and folder within that bucket. If you already have an Amazon S3 bucket and folder with the appropriate permissions, you can skip to Step 3: Upload Your Backup to Amazon S3.

To create an Amazon S3 bucket

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Follow the instructions for creating an Amazon S3 bucket in Creating a Bucket in the Amazon Simple Storage Service Console User Guide.

    The name of your Amazon S3 bucket must be DNS-compliant. Otherwise, ElastiCache can't access your backup file. The rules for DNS compliance are:

    • Names must be at least 3 and no more than 63 characters long.

    • Names must be a series of one or more labels separated by a period (.) where each label:

      • Starts with a lowercase letter or a number.

      • Ends with a lowercase letter or a number.

      • Contains only lowercase letters, numbers, and dashes.

    • Names can't be formatted as an IP address (for example, 192.0.2.0).

    We strongly recommend that you create your Amazon S3 bucket in the same AWS Region as your new ElastiCache for Redis cluster. This approach makes sure that the highest data transfer speed when ElastiCache reads your .rdb file from Amazon S3.

    Note

    To keep your data as secure as possible, make the permissions on your Amazon S3 bucket as restrictive as you can. At the same time, the permissions still need to allow the bucket and its contents to be used to seed your new Redis cluster.

To add a folder to an Amazon S3 bucket

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the bucket to upload your .rdb file to.

  3. Choose Create folder.

  4. Enter a name for your new folder.

  5. Choose Save.

    Make note of both the bucket name and the folder name.

Step 3: Upload Your Backup to Amazon S3

Now, upload the .rdb file that you created in Step 1: Create a Redis Backup. You upload it to the Amazon S3 bucket and folder that you created in Step 2: Create an Amazon S3 Bucket and Folder. For more information on this task, see Add an Object to a Bucket. Between steps 2 and 3, choose the name of the folder you created .

To upload your .rdb file to an Amazon S3 folder

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the Amazon S3 bucket you created in Step 2.

  3. Choose the name of the folder you created in Step 2.

  4. Choose Upload.

  5. Choose Add files.

  6. Browse to find the file or files you want to upload, then choose the file or files. To choose multiple files, hold down the Ctrl key while choosing each file name.

  7. Choose Open.

  8. Confirm the correct file or files are listed in the Upload dialog box, and then choose Upload.

Note the path to your .rdb file. For example, if your bucket name is myBucket and the path is myFolder/redis.rdb, enter myBucket/myFolder/redis.rdb. You need this path to seed the new cluster with the data in this backup.

For additional information, see Bucket Restrictions and Limitations in the Amazon Simple Storage Service Developer Guide.

Step 4: Grant ElastiCache Read Access to the .rdb File

Now, grant ElastiCache read access to your .rdb backup file. You grant ElastiCache access to your backup file in a different way depending if your bucket is in a default AWS Region or an opt-in AWS Region.

AWS Regions introduced before March 20, 2019, are enabled by default. You can begin working in these AWS Regions immediately. Regions introduced after March 20, 2019, such as Asia Pacific (Hong Kong) and Middle East (Bahrain), are disabled by default. You must enable, or opt in, to these Regions before you can use them, as described in Managing AWS Regions in the AWS General Reference.

Choose your approach depending on your AWS Region:

Grant ElastiCache Read Access to the .rdb File in a Default Region

AWS Regions introduced before March 20, 2019, are enabled by default. You can begin working in these AWS Regions immediately. Regions introduced after March 20, 2019, such as Asia Pacific (Hong Kong) and Middle East (Bahrain), are disabled by default. You must enable, or opt in, to these Regions before you can use them, as described in Managing AWS Regions in the AWS General Reference.

To grant ElastiCache read access to the backup file in an AWS Region enabled by default

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the S3 bucket that contains your .rdb file.

  3. Choose the name of the folder that contains your .rdb file.

  4. Choose the name of your .rdb backup file. The name of the selected file appears above the tabs at the top of the page.

    Image: File selected in S3 console
  5. Choose Permissions.

  6. If aws-scs-s3-readonly or one of the canonical IDs in the following list is not listed as a user, do the following:

    1. Under Access for other AWS accounts, choose Add account.

    2. In the box, add the AWS Region's canonical ID as shown following:

      • AWS GovCloud (US-West) Region:

        40fa568277ad703bd160f66ae4f83fc9dfdfd06c2f1b5060ca22442ac3ef8be6
        Important

        The backup must be located in an S3 bucket in AWS GovCloud (US) for you to download it to a Redis cluster in AWS GovCloud (US).

      • AWS Regions enabled by default:

        540804c33a284a299d2547575ce1010f2312ef3da9b3a053c8bc45bf233e4353
    3. Set the permissions on the bucket by choosing Yes for the following:

      • Read object

      • Read object permissions

    4. Choose Save.

  7. Choose Overview, and then choose Download.

Grant ElastiCache Read Access to the .rdb File in an Opt-In Region

AWS Regions introduced before March 20, 2019, are enabled by default. You can begin working in these AWS Regions immediately. Regions introduced after March 20, 2019, such as Asia Pacific (Hong Kong) and Middle East (Bahrain), are disabled by default. You must enable, or opt in, to these Regions before you can use them, as described in Managing AWS Regions in the AWS General Reference.

To grant ElastiCache read access to the backup file in an opt-in AWS Region

  1. Sign in to the AWS Management Console and open the Amazon S3 console at https://console.aws.amazon.com/s3/.

  2. Choose the name of the S3 bucket that contains your .rdb file.

  3. Choose the name of the folder that contains your .rdb file.

  4. Choose the name of your .rdb backup file. The name of the selected file appears above the tabs at the top of the page.

    Image: File selected in S3 console
  5. Choose the Permissions tab.

  6. Under Permissions, choose Bucket policy.

  7. Update the policy to grant ElastiCache required permissions to perform operations:

    • Add [ "Service" : "region-full-name.elasticache-snapshot.amazonaws.com" ] to Principal.

    • Add the following permissions required for exporting a snapshot to the Amazon S3 bucket:

      • "s3:GetObject"

      • "s3:ListBucket"

      • "s3:GetBucketAcl"

    The following is an example of what the updated policy might look like.

    { "Version": "2012-10-17", "Id": "Policy15397346", "Statement": [ { "Sid": "Stmt15399483", "Effect": "Allow", "Principal": { "Service": "ap-east-1.elasticache-snapshot.amazonaws.com" }, "Action": [ "s3:GetObject", "s3:ListBucket", "s3:GetBucketAcl" ], "Resource": [ "arn:aws:s3:::example-bucket", "arn:aws:s3:::example-bucket/backup1.rdb", "arn:aws:s3:::example-bucket/backup2.rdb" ] } ] }

Step 5: Seed the ElastiCache Cluster With the .rdb File Data

Now you are ready to create an ElastiCache cluster and seed it with the data from the .rdb file. To create the cluster, follow the directions at Creating a Cluster or Creating a Redis Replication Group from Scratch. Be sure to choose Redis as your cluster engine.

The method you use to tell ElastiCache where to find the Redis backup you uploaded to Amazon S3 depends on the method you use to create the cluster:

Seed the ElastiCache for Redis cluster or replication group with the .rdb file data

  • Using the ElastiCache console

    After you choose the Redis engine, expand the Advanced Redis settings section and locate Import data to cluster. In the Seed RDB file S3 location box, type in the Amazon S3 path for the files(s). If you have multiple .rdb files, type in the path for each file in a comma separated list. The Amazon S3 path looks something like myBucket/myFolder/myBackupFilename.rdb.

  • Using the AWS CLI

    If you use the create-cache-cluster or the create-replication-group operation, use the parameter --snapshot-arns to specify a fully qualified ARN for each .rdb file. For example, arn:aws:s3:::myBucket/myFolder/myBackupFilename.rdb. The ARN must resolve to the backup files you stored in Amazon S3.

  • Using the ElastiCache API

    If you use the CreateCacheCluster or the CreateReplicationGroup ElastiCache API operation, use the parameter SnapshotArns to specify a fully qualified ARN for each .rdb file. For example, arn:aws:s3:::myBucket/myFolder/myBackupFilename.rdb. The ARN must resolve to the backup files you stored in Amazon S3.

Important

When seeding a Redis (cluster mode enabled) cluster, you must configure each node group (shard) in the new cluster or replication group. Use the parameter --node-group-configuration (API: NodeGroupConfiguration) to do this. For more information, see the following:

During the process of creating your cluster, the data in your Redis backup is written to the cluster. You can monitor the progress by viewing the ElastiCache event messages. To do this, see the ElastiCache console and choose Cache Events. You can also use the AWS ElastiCache command line interface or ElastiCache API to obtain event messages. For more information, see Viewing ElastiCache Events.