The c5n.18xlarge is a compute-optimized AWS EC2 instance: 72 vCPU and 192 GiB of memory, 2.67 GiB per vCPU. In the name, "c" stands for compute, "5" is the generation, "n" marks enhanced networking and "18xlarge" is the size within the c5n family. It runs on Intel Xeon Platinum 8124M at 3 GHz, and AWS introduced it in November 2018. AWS has since shipped c6i, c7i, c8i and c9g. No single Spot node covers 72 vCPU and 192 GiB, so the equivalent is a fleet: 6 × ch.vs1.2xlarge, 96 vCPU and 192 GiB in total, about 94% below the US East (N. Virginia) on-demand rate. Spot delivers compute as managed Kubernetes, so a node pool of that size is the native shape of the answer rather than a workaround — provided the workload scales horizontally.
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c5n.18xlarge gives you 72 vCPU and 192 GiB in a single machine. The largest comparable Spot node, ch.vs1.2xlarge, is 16 vCPU and 32 GiB, so the equivalent here is 6 nodes rather than one.
Spot runs as managed Kubernetes, so a 6-node pool is the normal way to run things rather than a workaround. If your workload already sits behind a load balancer, a queue or a scheduler, it spreads across them without changes. If it needs all 72 cores and 192 GiB in one process, it does not.
