I am running ubuntu 16.04 server. I notice that upon boot, there is no text that scrolls by as services are being started, etc. After about 10-15 mins., I have a blank black screen, with no login prompt. I hit enter, and there is nothing. I press ctrl-alt-f1, and I get a terminal with yellow text. I do ctrl-alt-f2, and I get a terminal with white text. What is going on here?

Is this something new or is this first boot after a new install?

At boot time, do you get an option in the GRUB bootloader to boot into "Single User Mode" (or some such option). If so, give it a try and let us know what happens.

If your getting a terminal, you should be able to log in and find out what's going on! Did you try that? Sometimes on certain laptops the back light on the display is not driven properly. Take a flashlight and shine it at the screen during bootup, and see if there is a faint image of scrolling printk messages.

something is definitely going on, doesn't sound normal.
are you actually using that install as a server?
do you have a gui on that server? hopefully not...'
what "happened" before that?

I do not use a gui on my server.
Someone mentioned that plymouth may be the culprit.. here are results:

if the default terminal is not already 1, that was set by systemd startup scripts (ie, it made terminal n the startup terminal possibly running X, which was blank because of lack of keyboard, mouse, supported video card, or lack of background (no desktop installed, no twm))

if the terminal is yellow that's terminfo(1) /etc/terminfo and setterm(1)

if the terminal has a staircase effect during startup, thats:

# Set onlcr to avoid staircase effect.
stty onlcr 0>&1

if the screen is blank during boot, that could be many things: its' setup to display a logo instead of kernel text (which isn't showing), or even it simply uses a certain video card feature upon boot (mode setting) which doesn't clear until login

--------------------------------

your using a public distribution kernel which means it tries to "do everything for everyone"

the kernel is likely seeign you have some video chip, and doing something fancy to set you up for running XORG or wayland or (ubuntu now has it's own windows that has divererged from xorg and wayland, custom)

you should ignore the "problem" and just seek to set/change "runlevel" or startups so X is not started (you said you use text) and or just change the default TTY / VTY for login (not x login, terminal 1 text login). that used to be done in /etc/ inittab, but i can't say what systemd does. but google "systemd equivalent of inittab" and or systemd and login terminal

the color - as the person above said - you can see such details. you have a machine you can login to.

I'd also like to add that where as before text would scroll by showing what it was doing at start-up, now I just get a graphical ubuntu screen with loading dots.

would be nice to answer those questions (posted earlier) - especially: what happened before that?
If you think it is related to plymouth try to check this: https://wiki.ubuntu.com/Plymouth

^ yes.

so you are using it as a server.
there's no gui, yet there's plymouth? while not impossible in principle, this doesn't make any sense. purge plymouth.

I honestly can't recall what I've done, as it's been some time now. Maybe installed pihole? But I wouldn't think that would do this (but it did install some packages on its own...)