The m5zn.12xlarge pairs 48 vCPU with 192 GiB of RAM, the 4.00 GiB-per-vCPU ratio that marks a general-purpose instance. In the name, "m" is the general-purpose line, "5" is the generation, "zn" marks a higher clock and enhanced networking and "12xlarge" is the size within the m5zn family. It runs on Intel Xeon Platinum 8252 at 4.5 GHz, and AWS introduced it in December 2020. AWS has since shipped m6i, m7i, m8i and m9g; m6i.12xlarge is the direct replacement at this size. Spot's node ladder tops out below this size, so m5zn.12xlarge becomes 3 × gp.vs1.2xlarge (48 vCPU, 192 GiB combined), $3.96/hr on AWS in US East (N. Virginia), from $0.123/hr on Rackspace Spot. 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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m5zn.12xlarge gives you 48 vCPU and 192 GiB in a single machine. The largest comparable Spot node, gp.vs1.2xlarge, is 16 vCPU and 64 GiB, so the equivalent here is 3 nodes rather than one.
Spot runs as managed Kubernetes, so a 3-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 48 cores and 192 GiB in one process, it does not.
