Create the following file as
/etc/sysctl.d/01-pidmax.conf, then reboot your
kernel.pid_max = 132
What it does
It limits the system to a maximum of 132 processes, which is typically not enough to complete a normal boot.
Why it works
This sets the highest process ID that the kernel can assign to a process to 132, effectively limiting the system to 132 processes in total.