PAS-C01 · Question #25
A company is migrating its SAP workloads to AWS. The company's IT team installs a highly available SAP S/4HANA system that uses the SAP HANA system replication cluster package on SUSE Linux…
The correct answer is C. Use an overlay IP address as a virtual IP address. E. Choose an overlay IP address outside the VPC CIDR block that hosts the application and the. In AWS, traditional virtual IP (VIP) addresses used in on-premises HA clusters do not work across Availability Zones because each AZ has its own subnet with a distinct CIDR block. After failover to a node in a different AZ, the original VIP is no longer reachable because it…
Question
A company is migrating its SAP workloads to AWS. The company's IT team installs a highly available SAP S/4HANA system that uses the SAP HANA system replication cluster package on SUSE Linux Enterprise Server. The IT team deploys the system by using cluster nodes in different Availability Zones within the same AWS Region. After the initial launch of the SAP application, the application is accessible. However, after failover, the IT team cannot access the application even though the system is up and running on the secondary node. After investigation, an SAP solutions architect discovers that the virtual IP address has not been used correctly. Which combination of steps should the SAP solutions architect take to resolve this problem? (Choose two.)
Options
- AUse an overlay IP address as a secondary IP address with the primary node of the cluster.
- BChoose an overlay IP address within the VPC CIDR block that corresponds with the secondary
- CUse an overlay IP address as a virtual IP address.
- DChoose an overlay IP address within the VPC CIDR block that corresponds with the primary node
- EChoose an overlay IP address outside the VPC CIDR block that hosts the application and the
How the community answered
(29 responses)- A10% (3)
- B7% (2)
- C79% (23)
- D3% (1)
Explanation
In AWS, traditional virtual IP (VIP) addresses used in on-premises HA clusters do not work across Availability Zones because each AZ has its own subnet with a distinct CIDR block. After failover to a node in a different AZ, the original VIP is no longer reachable because it belongs to the source AZ's subnet. The AWS solution is an overlay IP address. (C) The overlay IP must be used as the virtual IP address - this is the address that clients connect to and that gets routed to whichever node is currently primary. (E) The overlay IP must be chosen from outside the VPC CIDR block - this is critical. Because the IP is outside the VPC CIDR, AWS does not auto-route it; instead, the cluster software updates the VPC route table entry for that overlay IP to point to the active node's Elastic Network Interface (ENI). This works seamlessly across AZs because route table updates are VPC-wide. Options B and D (choosing an IP within the VPC CIDR of either node's subnet) would conflict with existing subnet routing and cannot be reassigned across AZs. Option A (overlay IP as secondary IP on primary node) is incorrect because a secondary IP on an ENI stays bound to that AZ's subnet.
Topics
Community Discussion
No community discussion yet for this question.