The c6g.large is a compute-optimized AWS EC2 instance: 2 vCPU and 4 GiB of memory, 2.00 GiB per vCPU. In the name, "c" stands for compute, "6" is the generation, "g" marks AWS Graviton (ARM) processors and "large" is the size within the c6g family. It runs on AWS Graviton2 Processor at 2.5 GHz, and AWS introduced it in June 2020. AWS has since shipped c7g, c8g and c9g; c7g.large is the direct replacement at this size, scoring 51,891 CoreMark/s against this instance's 40,301 — roughly 29% more throughput for the same vCPU count. Rackspace Spot's ch.vs2.medium is a like-for-like substitute at 2 vCPU and 4 GiB, $0.068/hr on AWS in US East (N. Virginia), from $0.002/hr on Rackspace Spot.
Match qualityx86 substitution
c6g.large is Graviton (arm64). Rackspace Spot does not have arm64 servers, so ch.vs2.medium is an x86_64 substitute with similar specs.
You will need x86 builds of your container images. Most software rebuilds without changes, but anything with compiled native code needs a real rebuild rather than a retag. Speed per core also differs between the two chips, so it is worth testing before deciding how many nodes to run.
