Morning people, how do you manage to wake up early like 5 am as a computer person?

If i really need to wake up early I chug a couple liters of water right before bed.
To fall asleep quicker I listen to an audiobook with sleep timer and the lights out.

I notice that when I'm tired, dehydrated, or starving, my mind gets razor sharp and I become hyper focused.
I used to think that made me think better, but over time I've realised that sharpness =/= smarter.
Whatever logic I was holding in my head at 2am that I needed to put to screen actually wasn't as amazing as I thought it was, but my tired yet focused brain convinced me that it was genius.
Once I made that connection, I just started leaving TODOs in my comments of roughly what I was going for, and then go to sleep, reassuring my panicked brain that its "genius" can genuinely wait until morning for a clearer perspective.
I liken the experience to potheads who reach some half-baked inspiration that they can no longer put to words once cogent. It was never a great idea, it just interested you a lot in that heightened state.
In short: let go of your ideas. If they're truly amazing they'll still be there in the morning with a fresh pair of eyes.

If I need to get up at 5AM I just set my alarm and as soon as the alarm goes off I hop out of bed, to force myself to actually get up before I get the chance to start thinking about it (and postponing the getting up part).
As for what I do in the evening: if getting up at 5AM every day is my goal I just start by setting my alarm at 5, and aim to go to bed earlier. If I did go to bed late the night before, I would still set my alarm at 5 and just be tired the next day. Because the next day I'll feel so tired I'll automatically end up going to bed earlier. So it works itself out. So if I really wanted or needed to get up at 5AM every day I'd just do it even if I didn't sleep enough hours the night before. Once I'm in a routine I don't even need to set my alarm. I'll just automatically wake up at that hour.

If you always get up at 5am no matter when you go to bed, your body will eventually force you to go to bed at a decent time.

Go to bed at 9 pm. Get used to going to bed at that time. Your body will adjust.
- I do this same thing every night. No problems waking up at 5-6. It didn't take long to adjust to it.

Simple I sleep at 2 AM and wake up at 4.30-5.30 AM. Yeah my brain and body are fucked.

Biological alarm clock. AKA my kids wake me up.
- Use this one weird trick to hear a rendition of paw patrol sung as loud as they can at 4:30 am.
- I was going to say the same, ours wakes up way too early, and I'm looking forward to the teenage years when they want to sleep in and I get to wake em up.

I used to do this when I had a 1.5 hours commute (one way). If you can avoid it, don't do it. The world is not built for people that have to get up at 5 and be in bed by 10. I would run on 6.5 hours of sleep on average and I was constantly exhausted.
If you're a developer like me, it affects your productivity as well as your health. I would carpool, so I could nod off for a few winks on the way home. Sometimes when I was the one driving. It's bad for you. Don't do it.
If you must do it, the key is to make it a habit. Go to bed at the same time every night. Give yourself enough time to fall asleep and get a full 7-8 hours. Put away devices. Avoid any caffeine and alcohol after lunch. Get in shape if you can, it will help you sleep better. Avoid spicy foods in the evenings.
Stick to the schedule even on weekends, or at least don't try to make up for lost sleep then. It doesn't work.
You can still tinker, but you will have little time except weekends. Write down your ideas during the week and then hit the ground running when you have free time.
Don't forget to take time for yourself, family and touching some grass. Your computers will always be there. People will not.

Go to bed early. Easiest trick in the world.
You can also drink a bit of fluids before bed so your body naturally wakes up fairly early, the old Native American trick.
- Weak bladders beware, with this one trick you will wake up early. Not the way you want.

you all dont just wake up every 90 minutes no matter what?
- Get a sleep study done you might need medication or a CPAP
- does your brain run some kind of watchdog daemon?
  
  Mine apparently does. I can apparently will myself to wake up at a given time, or at least relatively close.

Go to bed reasonably early. The thing to watch/code/play will be there tomorrow. If you want to go out at night, do it on weekends. As for waking up, I'm used to it now (and my alarm clock app makes me solve a math problem to shut up :)) but long ago when I had trouble waking up, I'd put the alarm clock on a table on the other side of the room so I'd have to get up and walk over to shut it off. By the time that was done, blood is flowing and I'm awake.

I had issues with keeping a stable sleep schedule for years, but now I found a method that works for me: every day, set your alarm clock to the same time no matter what (in your case 5 AM) even on weekends. Then, try going to sleep so you always get full 8 hours, if you fuck up and go to sleep too late then tough shit - you'll feel tired tomorrow which will serve as a punishment that your brain will hopefully recognize.
They key is to be consistent and not sleep in.

brush your teeth and go to bed early and don't eat at least two hours before sleeping. Mostly though its the alarm. 6am is a big boundary for me and waking up before is just... fuuuuuuuuucccccccckkkkkkkkk... Im not talking preference. My preference is to wake up whenever but stupid modern world dominated by clocks and schedules. sigh.

Travel to a different time zone (-4hr), stay for 3 days, and come back. Hard set your bio clock :3
- Fuck yeah, vacation to Australia here i come!

You gotta prioritize sleep, that's the only answer.
I just got to bed as soon as my kids do, me.

I wake up at 5-5:30 every day without an alarm. I always get into bed an hour before I need to sleep and read a book while listening to lofi. It helps to calm me down and put me in a sleepy mood. I don't have a tv in the bedroom, which helps eliminate possible distractions. Just keep doing it every day for a while and your body will get used to the schedule.

My cats wake me up in the morning around the same time, regardless of when I go to bed.

i don't. do you really have to get up at 5!?
- Yeah, honestly why bother doing this shit? You got to enjoy your life, because you only have one. If you purposefullly forsake your life in favor of your Job, then you are doing Something wrong. Especialy since nobody will thank you in that Part.
  I have Had some shitty Chefs myself, but whenever they try to mention my being late, i ASK them very seriously (voice deep, tone down), If they got some issue with my Work results. Those ones pretty much stopped doing that asking Sometime Afterwards. Funny enough my last Boss wanted US all to meet daily at 8:30 for a Status Report (called daily b/c WE are "agile"). Stopped doing that after a year, when we Just sat there for a year in those Status Meeting Just answering the bare Minimum of His questions to our respective works. After a year, he started doing only a weekly (were we can submit things to discuss) at a better and more reasonable time. Which Made us all happier. So Fight won.
- I'm very much so on this team. Single digit hours are too early, frankly.

Alcohol in the evenings, cocaine for breakfast. ;p
Seriously though, melatonin in the evenings can help you drift off in conjunction with the no screen time. Alarms every 15 minutes in the morning, first one around two hours before clocking in so you got time to hit snooze a couple times and poop and shower, get dressed and still have commute time.

I go to bed at 8pvm

I force myself out of bed, stretch, down a glass of water, take my shower, then make an espresso. Each step gives me just enough energy to do the next step, and no more, and the espresso lasts only long enough to get to work and down another coffee.

My first meetings are at 6am, so I usually get up around 4am. I use two alarms because I'm fairly sleepy deprived. And I play on my phone for like 20 min while I wake up.
- I hear that jobs in astronomy don't pay like they used to.

My alarm includes my Apple Watch vibrating. And if I don’t get up on time I miss the train, and the next one isn’t for a whole ‘nother hour.

Biological clock. After doing it for months I know feel sleepy around 10am, hit the bed, and wake up around 5.30 everyday. I set an alarm at 6am just in case but I usually wake before it.

Melatonin helps me sort of "enforce" a bed time. Whenever I realise I'm itchin' for a binge, I pop 5mg of melatonin and I'm dozy within 30-45 minutes. And it's not the full system shutdown you get with sleeping pills, it just brings about that organic "need to sleep now, will continue tomorrow" feeling.
Also, aging "helps." I'm in my mid 30s and have noticed that my bed time has become progressively earlier - used to pull 6 hours of sleep (usually 2AM-8AM) without issues in my late 20s, now I feel almost hungover if I don't get my 8 hours and/or wake up after 8AM, and need to compensate with naps for about a week.
I haven't needed to wake up earlier than 7AM regularly for over a decade, though, so YMMV with these specifics. But I still do recommend giving melatonin a shot. The only caveat I have for it is that it may mess with your blood sugar levels, so 100% consult a physician beforehand if you have such issues.