The following diagram shows logical architecture diagram of the RKE cluster deployed on a two-layer PowerFlex cluster setup with four storage only nodes and three compute only nodes.

Figure 3.              Logical architecture

Each Storage Only node includes two Intel Xeon Skylake 8-core processors, 192 GB RAM, and six 3.84 TB SSDs. From the PowerFlex (previously VxFlex OS) standpoint, the Red Hat Enterprise Linux 7.6 Storage only nodes run the SDS component of PowerFlex to provide storage capacity. A single protection domain is created from these four SDS systems. A single storage pool is created within this Protection Domain from which persistent storage volumes can be provisioned for Kubernetes pods. The three ESXi 6.7 Compute only nodes run the SDC components of the PowerFlex in order to access the volumes created in the storage pool.

The RKE cluster is deployed as virtual machines on a VMware vSphere 6.7 cluster. For Rancher to work, the minimum hardware requirement to run Kubernetes node components is one CPU and 1 GB of memory. Considering CPU and Memory, it is recommended to host the different roles of the Kubernetes cluster (etcd, controlplane, and workers) on different nodes so that they can scale independently from one another. In this solution, each virtual machine is configured with 4 virtual CPUs, 8 GB RAM, and thick provisioned disks on the PowerFlex backend storage.

The management node hosts the vCenter appliance, PowerFlex Gateway, DNS, and workstation for RKE.

For detailed configuration of PowerFlex integrated nodes, see Appendix A: Configuration.