In order to attach storage volumes to EC2 host initiators, route tables associated between the Everpure Cloud Dedicated (PSC Dedicated) subnet and the EC2 host initiators subnet must allow iSCSI traffic to flow. There are two possible cases depending on where EC2 hosts are located.
Intra VPC Connectivity
Intra VPC connectivity refers to traffic flow between subnets in the same VPC. In most cases, route tables between subnets are set to "local", which allow traffic from any subnet range inside the VPC CIDR block. See the network diagram below.
Best Practices
It is recommended to keep EC2 hosts subnets on the same Availability Zone as PSC Dedicated subnet(s) to avoid data transfer egress charges.
Inter VPC Connectivity
Inter VPC connectivity can be achieved by leveraging VPC peering. VPC peering is used to establish network connection between two VPCs to allow traffic between them using private IP addresses. VPC peering doesn't allow transit communication; therefore, it is required to establish peering connecting between each VPC separately in 1:1 relationship.
There are three possible peering scenarios that fit PSC Dedicated host connectivity:
- Intra AZ peering: EC2 initiator hosts subnet are located in the same AZ as PSC Dedicated iSCSi subnet.
- Inter AZ peering: EC2 initiator hosts subnet are not located in the same AZ as PSC Dedicated iSCSi subnet.
- Inter Region peering: EC2 initiator hosts subnet are located in the different region.
Best Practices
- For same region VPC peering, It is recommended to keep EC2 hosts subnets on the same Availability Zone as PSC Dedicated subnet(s) to avoid data transfer egress charges.
- It is not recommended to attach a volume to an EC2 instance in a different region due to the high latency.
Transit Gateway
A Transit Gateway may be utilized to establish connectivity between Everpure Cloud Dedicated and EC2 hosts when they reside in different VPCs and within the same AZ. The use of a Transit Gateway to establish connectivity between a PSC Dedicated instance's VPC and EC2 host's VPC when they reside in different AZs is not supported.
Cross-Account VPC Connectivity
Cross-Account VPC connectivity can be established using the same VPC peering in the same account. Once you share VPC to another account using the account ID, the receiving account must accept the request to activate it.
You can use this document for a detailed procedure: Create a VPC peering connection with a VPC in another AWS account.
Each account has its own AZ mapping, make sure to map same AZ ID to avoid egress charges.
For more information check here Working with AZ IDs.