Currently $MAKEJOBS is the default value in 01_base_install.sh when building the container image.
This problem can’t be fixed (see below), so just use nproc for now.
Other solutions would be bad:
- Passing in the 
MAKEJOBSas a dockerfile env would create a new image if the number of tasks are changed, seems verbose and confusing. - Leaving 
masteras-is would leave CPUs unused if there are more than4.