A rift in the NTP world

https://lwn.net/SubscriberLink/713901/7bb511312e996566/

by Tomte • 9 years ago

173 144 9 years ago

deelowe• 9 years ago

Ugh. Why can't people just act civilized to each other? I can't believe this type of empire building goes on even for projects as auturistic has NTP.

adekok• 9 years ago

There are a large percentage of people for whom power games are more important than getting things done. See narcissism, cluster B, etc.

Those people are toxic, and removing them from your community makes everything better. If you can't do that, ensure that the only topics of discussion are reality based, and focussed on getting things done.

I'm not saying the people here meet those criteria. But it does answer your question.

okket• 9 years ago

And the winner of the battle between NTP (classic) and NTPsec is... chrony

https://chrony.tuxfamily.org/comparison.html

xenophonf5• 9 years ago

There's lots of good things chrony does that NTP doesn't and vice versa, but since chrony doesn't support Windows (roughly a third of the server market), I wouldn't claim that it's the clear winner.

curun1r• 9 years ago

Doesn't Microsoft have their own NTP implementations for use in the Windows world? IIRC, it's called Windows Time Service and it's included with Active Directory.

At a previous job, we pointed our in-office linux dev systems at our Windows domain controller and never had any issues with time synchronization. Since this was back in this embrace-and-extend days, I was pleasantly surprised by how interoperable MS was when it came to NTP.

derekp7• 9 years ago

I wonder how much the funding of NTPsec plays into this story? Funding is tied to the need for a project. If a project can claim an exaggerated need, then they can get more funding. So you end up with a conflict of interest when you hear one side's version of of reality.

gbrown_• 9 years ago

    Several years ago, the project's inadequate funding became known in the media
    and Stenn received partial funding from the Linux Foundation's Core
    Infrastructure Initiative, which was started after the discovery of how the
    minimal resources of the OpenSSL project left systems vulnerable to the
    Heartbleed vulnerability.

No no no no. Yes more funding and resources are good for these things but Heartbleed did not come about because of that. It came about to due broken development practices and the developers focusing on adding more features rather than working through the issues people had reported in their bug tracker.

The work done in NTPsec echos this in what seems to be a repeat of OpenSSL/ LibreSSL with NTP/ NTPsec.

Yes forking is the "easy way out" in these circumstances and it's a shame to see efforts split in such projects but in reality it's often what's needed to get things moving in the right direction.

falcolas2• 9 years ago

broken development practices and the developers focusing on adding more features rather than working through the issues

Both of those problems are easily attributed to a lack of funding. Fulfilling feature requests generates money, fixing bugs does not. When you can only afford to spend 10 hours a week on a project, you're going to end up cutting corners to work around those time limits.

HedgeMage9• 9 years ago

In the case of Network Time Foundation, the nonprofit wrapper for NTP classic, the problem was largely mismanagement of funding. NTF funded Harlan Stenn's work on NTP, but funded no other developers. It did, however, fund a fundraiser and two part-time administrative staff. The two administrative staff came to one FTE (full-time-equivalent) total, and I forget how much the fundraiser was working. In any case, the org had funded more FTE in overhead than in technical staff.

By contrast, the temporary rescue team funded a project-manager-slash-information-security-officer, three developers, and a bright intern who did a great deal of documentation work. Granted, these were not all full-time positions, and I was able to lean on my parent organization for administrative support, so while paperwork was minimal I didn't have to fund it directly.

NTPSec's staff has varied over time, but at the time I stepped down to hand the ISO role off to my successor, they had the following funded positions: a project manager, an ISO, two developers, and a sysadmin-slash-developer. (Note: not all of these were full-time positions, and some were funded by third parties rather than by NTPSec directly.)

Open source infrastructure software projects, when well run, do not spend over half their resources on non-development work. It's just not responsible. It's how you lose donor confidence, and how you fail to maintain good software engineering practice even when you have the resources to do better.

This has been a running theme in open source failures in the last few years: "it will be better if we throw more money at it!". Sometimes this is true: there are developers out there simply burning out for lack of resources and splitting their attention between OSS work and making a living. However, often, there is mismanagement at work, or the project doesn't have a good enough talent pool to pull from to use funds effectively when they do get funds. I love when the problems are purely technical, because it's a clean fix and everyone thanks me and I walk away quietly. When the underlying problems are social, they tend to fester, because nobody really wants to be in the hot seat over the disagreements that happened.

HedgeMage9• 9 years ago

This is pretty much what happened. We spent a few months working with Mr. Stenn, and ultimately he did not agree to pursue strategies to correct the underlying problems that caused NTP's security and stability issues. Simply patching known vulns and moving on would have been a temporary solution: more vulns were lurking. NTPSec was born to give the code base another chance, to evolve with a different strategy. In the end, I tend to feel that this is a strength of OSS: different groups are free to do things different ways, and if people are paying attention, software quality should win out.

Since Eric and the rest of my team started working on the NTP code base in early 2015, we've eliminated over 50% of its vulnerabilities before they were disclosed simply by applying good software engineering practice where it hadn't been. In the year before my O'Reilly presentation, it was more like 80 or 85 percent. Everything we hadn't eliminated by disclosure or discovery time was fixed promptly.

There are other NTP protocol implementations besides NTP classic or NTPSec that are worth considering for some users. However, we felt that refactoring the reference implementation was necessary due to its use in many less-mainstream, but often highly-critical (in a life-critical or economically-critical or critical-to-scientific-research sense) applications. The non-NTP-related implementations don't always do what high speed trading houses need, or scientific installations built on aging but extremely precise equipment need, or controls system interfaces need, and on and on and on. We just didn't have a drop-in replacement available for all of the things that weren't web servers, workstations, and other commodity applications.

The "rift" article is now subscriber-only, so I can't respond there to its many inaccuracies (I was passed a PDF by someone who cached it, this is the only way I was able to read it). I was never contacted about it by the author, and I don't feel it was a fair treatment of the subject. That's okay. I learned a long time ago that fixing a mess will make some people thank you and some people angry with you. It wouldn't have become a mess by the time I found it if there weren't a cost to fixing it. People who fear controversy will have a hard time making a difference in the world.

I'm at work, but I'll do my best to answer any questions fired at me today on this thread. If there's something you want to know, ask!

philh• 9 years ago

In the podcast, Sons depicted NTP as a faltering project run by out-of-touch developers. According to Sons, the build system was on one server whose root password had been lost.
Stenn denied many of Sons's statements outright. For example, asked about Sons's story about losing the root password, he dismissed it as "a complete fabrication."

Unless either you or Stenn is outright lying (neither of which seems likely, on priors), this seems like a strange misunderstanding to crop up. Do you know what's going on with this?

peterwwillis2• 9 years ago

From the article (and the end result) it seems the "strategies" you talk about that were rejected include a total rewrite and an abandonment of features and platform support.

You can eliminate vulns and improve stability a lot of ways. Total rewrite is definitely not the best way. Even if you're the best programmer in the world, rewrites often run into old bugs as well as new ones, and require a lot of testing and a lot of repeated effort.

And I can't speak for the other infosec nerds, but for me, name-dropping ESR does the opposite of inspiring confidence in a security-focused project. I wouldn't trust him to secure my shoelaces.

If the old codebase was really bad, perhaps eventual rewrite would have been useful. But what would help existing users more is fixing the existing product so they can upgrade in place and be more secure, and not forcing them to go through a whole product migration cycle just for better security.

tptacek7• 9 years ago

NTPsec advocates keep saying "eliminated 50% of vulnerabilities <<<before they were disclosed>>>", as if there were another meaningful way to eliminate vulnerabilities from a codebase.

Can you provide a breakdown of the vulnerabilities NTPsec HAS and HAS NOT been vulnerable to, along with their severity (low: degrades time service, medium: provides a practical vector for corrupting integrity of time service, high: compromises integrity of the server itself) and whether they're exposed (a) in the default configuration, (b) in a configuration run widely on the Internet, or (c) in no configuration actually known to the project maintainers?

You clearly have the list somewhere, because everyone involved in the project has this statistic ready to quote.

If you don't have the severity and exposure breakdowns, that's OK. Post the list anyways. Maybe it'll be obvious what the severity and exposure is.

This business of counting vulnerabilities and claiming victories has been a problem for software security for two decades now. Ops people don't care about the vulnerability count, if the vulnerabilities left exposed in the codebase are the ones that get their servers popped.

scandox• 9 years ago

I see the strapline of NTPsec on Github is: "ntpsec/ntpsec: The NTP reference implementation, refactored".

So is it or isn't it?

A few quotes from ESR from here http://esr.ibiblio.org/?p=6881Interesting

tossing out as many superannuated features as I could
full of port shims for big-iron Unixes from the Late Cretaceous
I do have an an advantage because I’m very bright and can hold more complex state in my head than most people [speaks to attitude :)]
This differs dramatically from the traditional Unix policy of leaving all porting shims back to the year zero in place because you never know when somebody might want to build your code on some remnant dinosaur workstation or minicomputer from the 1980s.
Yet another important thing to do on an expedition like this is to get permission – or give yourself permission, or fscking take permission – to remove obsolete features in order to reduce code volume, complexity, and attack surface.
Then ntpdc was deprecated, but not removed – the NTP Classic team had developed a culture of never breaking backward compatibility with anything.
I shot ntpdc through the head

I don't know the facts in the case at all, but I can imagine if you were the existing maintainer, you'd find this language and attitude incredibly difficult to take. And after all if you're not being paid to work on it, why should you swallow your pride?

masklinn• 9 years ago

I see the strapline of NTPsec on Github is: "ntpsec/ntpsec: The NTP reference implementation, refactored".
So is it or isn't it?

It's technically correct since they started from the reference implementation then "refactored" it.

They're skirting real close to claiming they are the reference NTP implementation but not quite doing that, just leaving the door open for misunderstandings.

irishsultan• 9 years ago

Refactoring shouldn't change functionality.

someguydave17• 9 years ago

The concept that your protocol is defined by a "reference implementation" and not a well-written specification is moronic. Someone should be able to articulate unambiguously (with words) what the NTP protocol is and what it does.

Oxitendwe3• 9 years ago

You don't think removing dead code and needless complexity is a good thing? It seems to me like he's doing a very good and important job, there's no need whatsoever to retain support for systems many decades old at this point.

eridius6• 9 years ago

If those systems are still in use, then surely they need an NTP implementation.

gpvos• 9 years ago

What's the status of phk's ntimed? The planned release dates on http://nwtime.org/projects/ntimed/ were quietly shifted from 2016 to 2017 a few weeks ago, and I'm not seeing much happening at http://phk.freebsd.dk/time/ .

acqq4• 9 years ago

I expected it will be like that as I've read how PHK wrote about it.

Whoever comes to some big project sees only the small part of it that he immediately understands, and it appears to him as he can do it "much simpler." Yes he can, if he just does that small part. The problem is, the big projects actually do more. If you don't need the big project, you can use the small simple project too. Everybody has fun making something small. Maintaining something big -- that's the hard part, and we see from the article we comment to, it's again what the "saviors" want to avoid:

"[Their plan was] to rescue something, quote unquote, fix it up, and turn it over to a maintenance team."

scj• 9 years ago

From what I understand of ESR's claims, much of the removed functionality is support for older platforms. Unlike NTP Classic, he asserts POSIX and C99. Apparently, this has drastically reduced complexity/size.

Of course, I haven't worked on the NTP code. But given the described circumstances, I'm willing to entertain the argument that older features now cost more to maintain than they are worth.

bla2• 9 years ago

Searching for additional funding, Stenn contacted the Internet Civil Engineering Institute (ICEI) and began working with two of its representatives, Eric S. Raymond and Susan Sons.

Stenn said in a phone interview, "Then all of a sudden I heard they have this great plan to rescue NTP. I wasn't happy with their attitude and approach, because there's a difference between rescuing and offering assistance. [Their plan was] to rescue something, quote unquote, fix it up, and turn it over to a maintenance team."

Most of them, she said, "are older than my father.... [and] are not always up to date on the latest techniques and security issues." Many are burning out from trying to maintain critical code while working full time jobs, and Sons suggested that they "should be retired.

Wow. Keep away from the ICEI I suppose.

HedgeMage9• 9 years ago

I highly recommend that you watch my interview with Mac Slocum (video here: https://www.oreilly.com/ideas/the-internet-is-going-to-fall-... ) to find out what I actually said, rather than listen to a reporter saying what someone else said I said. I was misquoted.

mdekkers• 9 years ago

[...]began working with two of its representatives, Eric S. Raymond[...]

Usually signals the start of much drama.

xorcist2• 9 years ago

The presentation mentioned was where I learned of the project. It sounded very very strange to me. Script kiddies who don't what what NTP does, only that it's good for DDoSing? What what that about..?

I wasn't surprised to learn that the project one year later was caught up evaluating Rust vs Go. That's great and all, but it's not saving the Internet from "meltdown".

Anyone who needs a modern ntpd and doesn't need the refclock stuff should probably just go with chrony.

problems2• 9 years ago

Script kiddies who don't what what NTP does, only that it's good for DDoSing? What what that about..?

There were several large reflection issues in ntpd in the past few years which led it to become a popular DDoS method. Reflection is the big winner lately.

No need for a botnet, just scan UDP services, find ones which reply with large packets or a series of packets and then spoof your IP (easy from many VPS and dedicated server providers) and flood out requests for those large packets.

You can get amplification of 100x as much traffic with only a small request and it's quite challenging to trace back to the original source due to the spoofed packets.

xorcist2• 9 years ago

That much is well known. It's the other part that's questionable.

feld• 9 years ago

I'll bite. Which large VPS / dedicated server providers don't implement BCP38?

kyledrake• 9 years ago

If you're looking for a simple security-oriented ntpd, I can't recommend OpenNTPd enough. It's cross platform and available for most Linux distros in packages.

http://www.openntpd.org

I have a much higher trust level for OpenBSD on security issues than I do with either of these projects.

ars2• 9 years ago

Just remember not to use OpenBSD or OpenNTP for time servers, they can only be used as clients.

(This is because neither supports leap seconds, so using them as servers will cause clients to desynchronize. Their belief that we don't need leap seconds is quite irrelevant: Right now we have them.)

iso-8859-12• 9 years ago

What do you mean when you say "we have them"? Because they are in UTC?

RFC5905 (NTP 4) notes:

    The goal of the NTP algorithms is to minimize
    both the time difference and frequency difference between UTC and the
    system clock.  When these differences have been reduced below nominal
    tolerances, the system clock is said to be synchronized to UTC.

Since nominal tolerances are not defined in the standard, a server would still be NTP conforming if it smeared the leap second.

mjw10072• 9 years ago

I tried using OpenNTPd as the ntp client on a slow virtual server last year.

It seemed like perfectly decent software except for the fact that it failed to keep the time in sync.

I switched to the usual (ntp.org) ntpd, with the same pool servers, and it worked fine.

iso-8859-12• 9 years ago

Did you try to diagnose the problem or did you just switch? I can't take such a vague bug report seriously.

xenophonf5• 9 years ago

From the article:

Most of them, [Sons] said, "are older than my father.... [and] are not always up to date on the latest techniques and security issues." [...] Sons suggested that they "should be retired."

That is incredibly asinine and discriminatory to boot.

From the NTPsec project manager's comment:

The main point of contention that caused the fork was BitKeeper vs Git.

I can't believe that arguing over VC tooling is what caused the fork. Why not just compromise on this, use BitKeeper for long enough to get on the maintainer's good side, and helpfully offer to convert to Git later? This is how ESR got GNU Emacs development migrated from Bazaar to Git, and it seemed to have gone pretty well for all involved.

gwu78• 9 years ago

I am too lazy to look it up on the mailing lists but a while back I recall ESR contacted certain BSD projects trying to convince them to change to Git. I mistook it for the occasional incoherent spam that slips through the filters.

zeveb2• 9 years ago

I am too lazy to look it up on the mailing lists but a while back I recall ESR contacted certain BSD projects trying to convince them to change to Git.

They're mostly still on CVS these days, right? Regardless of one's personal feelings about esr, is there any good reason to stay on CVS in this, the second decade of the twenty-first century?

saul_goodman• 9 years ago

People live forever, why should anyone try to take up the reigns from the older generation? I think it's clear, even if you don't like some of Sons's attitude, that this was a sound-bity quote likely taken a little out of context.

And why do people fork a project when they want to fix things? I'm sure there were dozens of problems in getting started on fixing NTP, BitKeeper was just the first problem to deal with. What can you do when the current maintainer is so contrary that they have already lost access to free funding to modernize a dying code base? We don't need NTP backported to unix workstations that EOL'd over a decade ago, we need an NTP that doesn't cause more problems than it solves.

eridius6• 9 years ago

I'm struggling to imagine a context that excuses the attitude of "that developer should be forced to retire so we can take over their project".

HedgeMage9• 9 years ago

That's simply not what I said; I was misquoted. Please watch the original video.

https://www.oreilly.com/ideas/the-internet-is-going-to-fall-...

It's amazing* how many people here are willing to roast me over a third-hand account of my opinions, when I've already offered to answer questions directly.

* Not actually amazing, fairly typical of internet commentary, really.

areyousure• 9 years ago

To save effort on finding the relevant segment of a 17+ minute interview, I have attempted to transcribe a portion. See also https://www.oreilly.com/ideas/susan-sons-on-maintaining-and-... with some portions transcribed (inexactly); add ~20s to the times below to match the podcast timing.

(5:26) [O'Reilly interviewer] Mac Slocum: Related question on this: how can the Internet's infrastructure remain up to date and secure, particularly when it's distributed like this?

(5:33) Susan Sons: So the really terrifying thing about infrastructure software in particular is when you pay your ISP bill, that pays for all the cabling that runs to your home or business. That pays for the people that work at the ISP. That pays for their routing equipment and their power and their billing systems and their marketing and all of these wonderful things. It doesn't pay for the software that makes the Internet work. (5:54) That is maintained almost entirely by volunteers. And those volunteers are aging. [Um.] Most of them are older than my father. And [um,] we're not seeing a new cadre of people stepping up and taking over their projects, (6:10) so what we're seeing is ones and twos of volunteers who are hanging on and either burning out while trying to do this in addition to a full-time job, or are doing it instead of a full-time job, or should be retired, or are retired. [Um.] And it's just not giving the care it needs. (6:27) And in addition to this, these people aren't always up to date on the latest [um] techniques and security concerns of the day. And the next generation isn't coming up. I recently started a mentoring group called the #newguard that takes early and mid-career technologists and we cross-mentor and then we match them up with the old guard who are maintaining and who built this software to try to help solve that problem. But in the meantime there's still not enough funding going in this direction. And there's not enough churning happening. [Um.] And it's a really tough thing because there's a certain amount of what I call "functional arrogance" involved. [Um.] I don't have a certificate of "Susan is good enough to save the Internet" anywhere. I don't know who hands those out.

(7:08) Slocum: Sure.

mcguire6• 9 years ago

2:15 The entire build system depended on one build server located in Harlan Stenn's home. "But Harlan no longer had the root password to this system, couldn't update it, didn't know what scripts were running on it, and no one in in the world could build NTP without this server continuing to function."

3:25 It was death by a thousand cuts. "And I was seeing things that were not yet C99 compliant in 2015. The status of the code was over 16 years out of date in terms of C coding standards which means that you can't use modern tools for static analysis..."

4:30 "And in the mean time, security patches were being circulated secretly and then being leaked, and the leaked patches were being turned into exploits which we were seeing in the wild very quickly, when the security patches weren't being seen in the wild for a long time."

6:00 "...but it doesn't pay for the software that makes the Internet run. That maintained almost entirely by volunteers, and the volunteers are ageing, most of them are older than my father. And we're not seeing new [?] people stepping up..."

bluefox• 9 years ago

Yes, it's quite sad.

https://blog.cr.yp.to/20160607-dueprocess.html

xenophonf5• 9 years ago

I found your remarks about succession planning at around the 5:50 mark of the linked video:

[The software that makes the Internet work] is maintained almost entirely by volunteers, and those volunteers are aging. Most of them are older than my father, and we're not seeing a new cadre of people stepping up and taking over their projects, so what we're seeing is ones and twos of volunteers who are hanging on and either burning out while trying to do this in addition to a full-time job, or are doing it instead of a full-time job, or should be retired, or are retired, and it's just not getting the care it needs. And in addition to this, these people aren't always up to date on the latest techniques and security concerns of the day, and the next generation isn't coming up.

In context "should be retired" sounds awfully prescriptive, but I can see how that could mean something like "these volunteers want to retire but feel obligated to continue their maintenance duties".

Then at the 7:00 mark, you say:

It's a really tough thing because there's a certain amount of what I call functional arrogance involved... There's a certain point where you just have to say, "I'm going to decide that I'm in charge of this"...

I dunno. I can see where that's going to rub people the wrong way while at the same time seeing the value in having some moxie. I get the impression, though, that Stenn wasn't too happy with this approach.

Animats• 9 years ago

Most of them, [Sons] said, "are older than my father....

Eric S. Raymond, who seems to be behind the "young" fork, is 59.

loeg2• 9 years ago

To be fair, that is technically younger than my father. By 3 years.

itp• 9 years ago

ESR seems to have a long track record of being involved in these types of events. There are obviously a number of possible conclusions to draw:

  - ESR is so productive and involved in so many things that this is actually a normal drama ratio
  - ESR only involves himself in critical issues with high potential for drama
  - ESR brings the drama

I can't rule out either of the first two, but years of data points lead me to believe it's the third.

linuxkerneldev• 9 years ago

I agree that it is very likely to be the third. Just have a read of some of ESR's articles. Eg:

http://esr.ibiblio.org/?p=129

" American blacks average a standard deviation lower in IQ than American whites at about 85. And it gets worse: the average IQ of African blacks is lower still, not far above what is considered the threshold of mental retardation in the U.S. And yes, it’s genetic; g seems to be about 85% heritable, and recent studies of effects like regression towards the mean suggest strongly that most of the heritability is DNA rather than nurturance effects. "

ESR's famous melodramatic-response to having his CML2 ("Eric's configuration markup language for kernel building") patch rejected by Linus is also quite telling about his self-perception and his perception of other people and his interaction with anyone who would have an opposing viewpoint to his.

IgorPartola• 9 years ago

Eek. That post contains quite a lot of claims that are not backed by a single reference to a primary source.

thehardsphere6• 9 years ago

How does the quote show that he "brings the drama"? I mean, that's on his own blog. It's not like he's exporting that. It's not like he's going up to black people and saying "you're almost retarded."

I think the CML incident and the time where he yelled at some Debian developer about "our tribe" are better examples, because at least there he's going into other people's spaces and actually confronting them.

tptacek7• 9 years ago

ESR's politics are repugnant, but there's more than enough evidence of job-related narcissism to make an argument about his personality (if that's needed) without having to drag the thread through his profuse bigotry. That's what Twitter's for.

I'm not sure how much more needs to be said beyond the fact that ESR has repeatedly claimed, including recently, that the Internet might fail if people don't continue to donate to his Patreon --- a Patreon which, he has previously stated, stands as direct evidence of his fame as a programmer, a fame rivaling that of Donald Knuth or Linus Torvalds.

phjesusthatguy3• 9 years ago

I was under the impression that he wrote fetchmail, but according to wikipedia he took over a previous package and renamed it fetchmail. So AFAIK, he's notable because he said so.

Yes, I know I'm nobody but that doesn't mean I can't call bullshit when I smell it.

jcoffland3• 9 years ago

There is little doubt that ESR is notable. He is best known as the writer of essays about Open-Source such as The Cathedral and the Bazaar and The Magic Cauldron as well as others on many topics including gun rights. He suffers from cerebral palsy but has not let that hold him back. He is also known for being contentious. Arguably, his philosophical contributions are more valuable than his code contributions.

someguydave17• 9 years ago

Why not get rid of NTP altogether? For servers, they ought to be able to accept a hardware time and frequency inputs. Typically this would mean a 1 Pulse-Per-Second (PPS) signal and a 10 MHz signal. You might also want some kind of serial signal that describes the date and time to label the last second pulse.

Why don't any professional servers come with this kind of connection built-in? Why can't I synchronize my Xeon chip's clock to my own reference frequency?

xenophonf5• 9 years ago

1-second-per-second is a difficult engineering challenge:

https://rachelbythebay.com/w/2014/06/14/time/ (associated HN discussion - https://news.ycombinator.com/item?id=8066915)

Here's a choice quote from the NTP FAQ (http://www.ntp.org/ntpfaq/NTP-s-sw-clocks-quality.htm):

Unfortunately all the common clock hardware is not very accurate. This is simply because the frequency that makes time increase is never exactly right. Even an error of only 0.001% would make a clock be off by almost one second per day. This is also a reason why discussing clock problems uses very fine measures: One PPM (Part Per Million) is 0.0001% (1E-6).

And if you want to delve into the physics, you'll enjoy this tutorial by John Vig (U.S. Army Communications-Electronics Command):

http://www.am1.us/Local_Papers/U11625%20VIG-TUTORIAL.pdf

someguydave17• 9 years ago

That might have been true awhile ago, but today you can get GPS-disciplined oscillators that can produce 1 PPS accurate down to tens of nanoseconds. By accurate, I mean "replicates what the NIST or USNO atomic clocks indicate."

someguydave17• 9 years ago

Also your "rachelbythebay" post is discussing exactly the problem I'm trying to solve with hardware - using software. You don't need to run NTPd at all if your computer hardware and infrastructure has solved the problem of "keep my clock accurate down to 10's nanoseconds."

Also, there's another unrelated problem which is "how accurately does a user process running in a linux kernel get the current time?". That's a problem no matter what kind of hardware the kernel is running on (although hardware might assist with that as well).

walrus015• 9 years ago

For servers, they ought to be able to accept a hardware time and frequency inputs. Typically this would mean a 1 Pulse-Per-Second (PPS) signal and a 10 MHz signal. You might also want some kind of serial signal that describes the date and time to label the last second pulse.

Because large numbers of servers in a mass-scale deployment frequently have only two things: Ethernet connections and power. Introducing coaxial cable so you can feed a 10MHz reference signal (such as you feed a reference clock signal to certain RF Rx and Tx equipment) is a non starter. Introducing a serial cable to every server into an environment that is purely IP/Ethernet is a non starter.

someguydave17• 9 years ago

So people would be willing to spend millions of dollars on computers and would also be unwilling to spend a few thousand more for cabling?

geofft2• 9 years ago

1. If I have a fleet of servers, it's a lot more important to maintain accurate time between the servers than accurate time in an absolute sense. If your hardware time cable can't span two racks, I don't want two separate clocks on each rack from a different hardware source.

2. For applications where you need extremely highly accurate time, there already are other solutions like PTP. NTP is mainly useful for wide-area connections. I want to keep my laptop's time accurate, so that if I modify a file here and rsync it elsewhere, make doesn't get confused about the time my laptop sent. I'm not plugging in a hardware time server to my laptop.

someguydave17• 9 years ago

PTP is more accurate than NTP, but not as accurate as a 1PPS line. However, PTP has the advantage that is bidirectional so it can solve the (non-trival) problem of correcting for propagation delays.

someguydave17• 9 years ago

If your hardware time cable can't span two racks, I don't want two separate clocks on each rack from a different hardware source.

It absolutely would span racks. You must account for the additional speed-of-light delay the cable itself would add though.

mcguire6• 9 years ago

I wonder how that would work with virtual servers?

someguydave17• 9 years ago

Does the hardware clock that runs the physical chip also provide a clock for the underlying virtual cpu?

jlgaddis3• 9 years ago

You can. The workstation in front of me is directly connected (via serial) to a GPS providing a 1PPS signal.

Everything else in my house uses NTP and, in some cases, PTP, however.

someguydave17• 9 years ago

Yes but the oscillator in your computer is almost certainly not referenced to a frequency reference. Also you are not able to correct that oscillator's frequency with your hardware (yes, you can estimate your frequency error from external PTP measurements but you cannot physically correct it - nor prevent drift).

throw7• 9 years ago

why was the buildsystem changed to waf? ugghh. ntpsec wants to lower barriers to entry just use/update autotools.

zeveb2• 9 years ago

I have no experience with waf, but I have some with autotools, and 'barrier to entry' is a good description of autotools. Also 'barrier to progress,' 'barrier to happiness' and 'barrier to sanity.'

makomk• 9 years ago

CMake is the usual choice of developers who don't want to deal with autotools these days. Making people learn yet another build system is not going to be popular.

mcguire6• 9 years ago

"[Sons] has since become president of ICEI; she described herself in the presentation as having "moved on" and is no longer involved with NTPsec on a daily basis."

"Already, where once only Stenn was looking for support, now Raymond is in a somewhat similar position, as NTPsec has lost its Core Infrastructure Initiative funding as of September 2016."

So, a drive-by fork.

BTW, had anyone used any project that ESR is heavily involved in? The only things I know about are NTPsec, fetchmail and his attempt to hack the Linux kernel build system.

jlgaddis3• 9 years ago

According to ESR, if you use a mobile phone, you're using his code (I assume this to refer to gpsd).

mcguire6• 9 years ago

"GPSD is everywhere in mobile embedded systems. It underlies the map service on Android [4.0 and after?] phones. It's ubiquitous in drones, robot submarines, and driverless cars. It's increasingly common in recent generations of manned aircraft, marine navigation systems, and military vehicles."

Interesting, thanks.

gumby• 9 years ago

Par for the course for Raymond: make a big noise, little motion, claim credit.

Stenn just gets things done.

disclaimer: have known Stenn since the 90s, Raymond casually since the 80s.

notacoward• 9 years ago

I read through some of the blog posts related to language choice for NTPSec (helpfully provided in LWN comments).

https://blog.ntpsec.org/

I can't help but wonder if there are other options, most notably C++. Don't get me wrong, I have a well developed loathing of C++ based on past experience, but it seems like a category fit and people I respect have said good things about the latest versions. Nim would also seem like a pretty good fit technically, though I could well understand if its relative immaturity and lack of developers (another recent story here on HN) cause it to be deemed inappropriate for this situation.

A rift in the NTP world

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