Use VPC Peering (AWS) to Connect to Apache Cassandra | Instaclustr

Table of Contents

Setting up VPC Peering

VPC Peering is a method for routing traffic between two VPC’s privately. For an overview on VPC Peering see the AWS VPC Peering Guide. Instaclustr supports VPC peering as a mechanism for connecting directly to your Instaclustr managed cluster, from your own client VPC. VPC Peering allows you to access your cluster via private IP and makes for a much more secure network setup.

Note: If you only intend to connect to your cluster from a peered VPC, then make sure to enable Use private IPs to broadcast for auto-discovery under Cassandra Setup when you create a new cluster, or create a private network cluster.  If you’re peering into an existing public ip cluster, contact support to change the nodes’ broadcast address over to private ip. If you intend to connect from both the peered VPC and other sources then you can refer to our support article to understand your options.

  1. Once your cluster has been provisioned, you can create a VPC Peering request through the Instaclustr console. Navigate to the VPC Peering tab of your cluster and then click on Add a New VPC Connection.
  2. Fill in the required information on the VPC Peering Connections and click the Submit VPC Peering Request button.
  3. If the request is successfully submitted, the Peering Connection will appear as a new entry in a table with a status of Pending Request.

  4. In order to accept the request, you will need to login to your AWS console to accept the peering request and add a route in your VPC to our VPC.In order to accept the peering request, login to the AWS VPC console and navigate to Peering Connections. Select the pending VPC peering connection and choose Actions, Accept Request.In order to add a route in your VPC to your cluster’s VPC, navigate to the main route table of your VPC and add a route to your cluster’s network address block. Under Target, select the Peering Connection that you have just created.

  5. We automatically generate the routes within our VPC to ensure traffic is routed correctly to your VPC. Once you have accepted the peering request, the VPC peering connection will show up as active in your Instaclustr dashboard.Note: If you have EC2 instances running in your VPC that need access to the peering connection, make sure that you create an explicit subnet association in your VPC’s main route table to the subnet of that instance.A list of all of your VNet peering connections.

Note: To test the peering, you may try netcat or telnet. Port 9042 is the exposed port for CQL:

A result of 0 indicates success.

A telnet prompt indicates success, enter quit to close the connection. The same test can be run using port 7077 to test Spark connectivity.


A duplicate request for this VPC Peering Connection already exists.

This indicates that an existing peering request for this Account, VPC and network combination already exists.  Check the Peering Connection table at the bottom of the page to verify.

If you still cannot connect to the cluster via your Peered VPC connection, confirm that you have accepted the peering request, through the AWS Console.

Peering Request status is “Failed”

The most common causes of a failed peering request are:

  • The VPC ID or the account ID of the peering VPC are incorrect
  • The CIDR ranges of the two VPCs overlap
    For example, your cluster network is and you are trying to peer it with a VPC in the range  Because AWS will need to route traffic for to the peered VPC, the overlap will conflict with addresses in the cluster network and is therefore rejected.
  • The cluster VPC and the client VPC are in different regions
    For example, your cluster is in US-EAST-1 and you are attempting to peer it with US-WEST-2.  AWS does not currently support cross-region VPC Peering connections.

Further details are available on the AWS site.

Using Inter-region VPC-peering, Direct Connect and AWS Transit Gateways

For customers running in their own AWS account, the following additional networking scenarios are supported through Instaclustr’s Custom VPC feature:

Inter-region VPC Peering for cross-datacenter communication in multi datacenter Cassandra clusters. (Note: Inter-region VPC Peering for client to cluster communication is supported using the mechanisms above.)

AWS Transit Gateways to either connect from clients to clusters or between data centers in a multi datacenter Cassandra cluster.

AWS Direct Connect for either on-prem client to AWS hosted cluster connections or connections between on-prem data centers and AWS data centers in multi datacenter, hybrid-cloud Cassandra clusters, or to use a private connection for traffic between two AWS data centers.

These use cases require manual configuration of the VPC connectivity and the design and maintenance of this configuration is a customer responsibility unless otherwise agreed.

By Instaclustr Support
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