@Nguyen Huu Minh Tri (UTOP.PROD) ML compute instance cannot be scaled up and down, It is only a single node that can be used for smaller workloads. It does provide some productivity tools like Jupyter notebook, Rstudio, ability to configure custom applications which can be automated to start and stop when required.
If you are looking at options to scale out, then compute cluster should be used which can be configured with the minimum and maximum nodes with the required instance types.
I hope this answers your question!!
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