Using Amazon Keyspaces with interface VPC endpoints - Amazon Keyspaces (for Apache Cassandra)

Using Amazon Keyspaces with interface VPC endpoints

Interface VPC endpoints enable private communication between your virtual private cloud (VPC) running in Amazon VPC and Amazon Keyspaces. Interface VPC endpoints are powered by AWS PrivateLink, which is an AWS service that enables private communication between VPCs and AWS services.

AWS PrivateLink enables this by using an elastic network interface with private IPs in your VPC so that network traffic does not leave the Amazon network. Interface VPC endpoints don't require an internet gateway, NAT device, VPN connection, or AWS Direct Connect connection. For more information, see Amazon Virtual Private Cloud and Interface VPC endpoints (AWS PrivateLink).

Using interface VPC endpoints for Amazon Keyspaces

You can create an interface VPC endpoint so that traffic between Amazon Keyspaces and your Amazon VPC resources starts flowing through the interface VPC endpoint. To get started, follow the steps to create an interface endpoint. Next, edit the security group associated with the endpoint that you created in the previous step, and configure an inbound rule for port 9142. For more information, see Adding, removing, and updating rules.

Populating system.peers table entries with interface VPC endpoint information

Apache Cassandra drivers use the system.peers table to query for node information about the cluster. Cassandra drivers use the node information to load balance connections and retry operations. Amazon Keyspaces populates nine entries in the system.peers table automatically for clients connecting through the public endpoint.

To provide clients connecting through interface VPC endpoints with similar functionality, Amazon Keyspaces populates the system.peers table in your account with an entry for each availability zone where a VPC endpoint is available. To look up and store available interface VPC endpoints in the system.peers table, Amazon Keyspaces requires that you grant the IAM entity used to connect to Amazon Keyspaces access permissions to query your VPC for the endpoint and network interface information.

Important

Populating the system.peers table with your available interface VPC endpoints improves load balancing and increases read/write throughput. It is recommended for all clients accessing Amazon Keyspaces using interface VPC endpoints.

To grant the IAM entity used to connect to Amazon Keyspaces permissions to look up the necessary interface VPC endpoint information, you can update your existing IAM role or user policy, or create a new IAM policy as shown in the following example.

{ "Version":"2012-10-17", "Statement":[ { "Sid":"ListVPCEndpoints", "Effect":"Allow", "Action":[ "ec2:DescribeNetworkInterfaces", "ec2:DescribeVpcEndpoints" ], "Resource":"*" } ] }

To confirm that the policy has been setup correctly, query the system.peers table to see networking information. If the system.peers table is empty, it could indicate that the policy hasn't been configured successfully or that you have exceeded the request rate quota for DescribeNetworkInterfaces and DescribeVPCEndpoints API actions. DescribeVPCEndpoints falls into the Describe* category and is considered a non-mutating action. DescribeNetworkInterfaces falls into the subset of unfiltered and unpaginated non-mutating actions, and different quotas apply. For more information, see Request token bucket sizes and refill rates in the Amazon EC2 API Reference.

If you do see an empty table, try again a few minutes later to rule out request rate quota issues. If your query returns results from the table, your policy has been configured correctly.

Controlling access to interface VPC endpoints for Amazon Keyspaces

VPC endpoint policies enable you to control access to resources in two ways:

  • IAM policy – You can control the requests, users, or groups that are allowed to access Amazon Keyspaces through a specific VPC endpoint. You can do this by using a condition key in the policy that is attached to an IAM user, group, or role.

  • VPC policy – You can control which VPC endpoints have access to your Amazon Keyspaces resources by attaching policies to them. To restrict access to a specific keyspace or table to only allow traffic coming through a specific VPC endpoint, edit the existing IAM policy that restricts resource access and add that VPC endpoint.

The following are example endpoint policies for accessing Amazon Keyspaces resources.

  • IAM policy example: Restrict all access to a specific Amazon Keyspaces table unless traffic comes from the specified VPC endpoint – This sample policy can be attached to an IAM user, role, or group. It restricts access to a specified Amazon Keyspaces table unless incoming traffic originates from a specified VPC endpoint.

    { "Version": "2012-10-17", "Statement": [ { "Sid": "UserOrRolePolicyToDenyAccess", "Action": "cassandra:*", "Effect": "Deny", "Resource": [ "arn:aws:cassandra:us-east-1:111122223333:/keyspace/mykeyspace/table/mytable", "arn:aws:cassandra:us-east-1:111122223333:/keyspace/system*" ], "Condition": { "StringNotEquals" : { "aws:sourceVpce": "vpce-abc123" } } } ] }
    Note

    To restrict access to a specific table, you must also include access to the system tables. System tables are read-only.

  • VPC policy example: Read-only access – This sample policy can be attached to a VPC endpoint. (For more information, see Controlling access to Amazon VPC resources). It restricts actions to read-only access to Amazon Keyspaces resources through the VPC endpoint it's attached to.

    { "Version": "2012-10-17", "Statement": [ { "Sid": "ReadOnly", "Principal": "*", "Action": [ "cassandra:Select" ], "Effect": "Allow", "Resource": "*" } ] }
  • VPC policy example: Restrict access to a specific Amazon Keyspaces table – This sample policy can be attached to a VPC endpoint. It restricts access to a specific table through the VPC endpoint that it's attached to.

    { "Version": "2012-10-17", "Statement": [ { "Sid": "RestrictAccessToTable", "Principal": "*", "Action": "cassandra:*", "Effect": "Allow", "Resource": [ "arn:aws:cassandra:us-east-1:111122223333:/keyspace/mykeyspace/table/mytable", "arn:aws:cassandra:us-east-1:111122223333:/keyspace/system*" ] } ] }
    Note

    To restrict access to a specific table, you must also include access to the system tables. System tables are read-only.

Availability

Amazon Keyspaces supports using interface VPC endpoints in all of the AWS Regions where the service is available. For more information, see Service endpoints for Amazon Keyspaces.

VPC Endpoint policies and Amazon Keyspaces point-in-time recovery (PITR)

If you are using IAM policies with condition keys to restrict incoming traffic, the table restore operation may fail. For example, if you restrict source traffic to specific VPC endpoints using aws:SourceVpce condition keys, the table restore operation fails. To allow Amazon Keyspaces to perform a restore operation on your principal's behalf, you must add an aws:ViaAWSService condition key to your IAM policy. The aws:ViaAWSService condition key allows access when any AWS service makes a request using the principal's credentials. For more information, see IAM JSON policy elements: Condition key in the IAM User Guide. The following policy is an example of this.

{ "Version":"2012-10-17", "Statement":[ { "Sid":"CassandraAccessForVPCE", "Effect":"Allow", "Action":"cassandra:*", "Resource":"*", "Condition":{ "Bool":{ "aws:ViaAWSService":"false" }, "StringEquals":{ "aws:SourceVpce":[ "vpce-12345678901234567" ] } } }, { "Sid":"CassandraAccessForAwsService", "Effect":"Allow", "Action":"cassandra:*", "Resource":"*", "Condition":{ "Bool":{ "aws:ViaAWSService":"true" } } } ] }