According to the Cisco AppDynamics Professional Implementer (CAPI) documents, the two recommendations for servers in an Events Service Cluster are:

Should be on the same local network ©: This is a valid recommendation because the Events Service Cluster is based on Apache Cassandra, which is a distributed database that relies on network communication between the nodes. Having the servers on the same local network reduces the network latency and improves the performance and reliability of the cluster. The network bandwidth should be at least 1 Gbps, and the network firewall should allow the required ports for the Events Service Cluster12.

Should have identical hardware specifications (D): This is a valid recommendation because the Events Service Cluster is horizontally scalable, which means that the nodes share the data storage and processing load equally. Having identical hardware specifications for the servers ensures that the cluster is balanced and efficient, and avoids performance bottlenecks or failures due to hardware differences. The hardware specifications should meet the minimum requirements for the Events Service Cluster, such as CPU cores, RAM, disk space, and disk type12.

The incorrect options are:

Should be installed using the same user account (A): This is not a valid recommendation because the Events Service Cluster does not require the same user account for installation. The user account that is used to install the Events Service Cluster should have sudo privileges on the target hosts, but it does not have to be the same for all the hosts. The user account that is used to run the Events Service Cluster should have read and write permissions on the installation directory, but it does not have to be the same for all the hosts either12.

Should have eight or more CPU cores (B): This is not a valid recommendation because the Events Service Cluster does not require eight or more CPU cores for the servers. The minimum requirement for the CPU cores is four, and the recommended requirement is six. Having more CPU cores may improve the performance of the cluster, but it is not a mandatory recommendation12.

Should be running the same operating system version (E): This is not a valid recommendation because the Events Service Cluster does not require the same operating system version for the servers. The Events Service Cluster supports various Linux operating systems, such as CentOS, Red Hat, Ubuntu, and SUSE. The operating system version should be compatible with the Events Service version, but it does not have to be the same for all the hosts12.

References:

1: Events Service Requirements - AppDynamics

2: Events Service Deployment - AppDynamics