[Box-Admins] daemontools versus systemd [was: source.squeak.org went down today]

[Chris Muller]

I'm glad this topic came up because I have "learn daemontools" coming
up on my list.  I'm a total newbie with it, but I think I want try
using it with my own servers soon.

But one thing I noticed when I google for it wants to bring me to
http://www.daemon-tools.cc/home, but the one Ken referred me to a
while back was http://cr.yp.to/daemontools.html.

Are these two the same thing or is the latter what I want?

Thanks.


On Tue, Oct 21, 2014 at 10:57 AM, Levente Uzonyi <leves at elte.hu> wrote:
> IMHO daemontools does what it offers, it supervises processes. In case of
> the source.squeak.org the image was up and running, but it was
> non-functional.
> Daemontools is not a system monitoring tool; it won't check the health of
> the services, it'll simply ensure that the processes are running.
> On the new boxes we can consider using monitoring tools.
>
> Levente
>
>
> On Tue, 21 Oct 2014, Chris Cunnington wrote:
>
>> Just on the topic, I find daemontools confounding. The svc tool is
>> supposed to start and stop processes, but I also find it doesn’t work. As I
>> understand it, svc is supposed to control a supervise process,
>> which overlooks a process like source.squeak.org. But how does that start
>> exactly? I think there’s more than one way. I think creating a symlink to to
>> the /service directory is supposed to do it. I’ve also
>> used something like “supervise foo&”, which I figure is a hack.
>> daemontools is great because it restarts processes automatically when
>> rebooting. But the svc and svstat haven’t proven that useful in my
>> experience. And daemontools is state-of-the-art 2004. I’m looking at
>> systemd (which netstyle.ch uses to start and stop its hundreds of client
>> images from requests sent to the box), which I think supersedes the
>> daemontools feature set. And I understand, it will be PID1 default
>> on some Linuxes in the near future. It is possible that sometime the use
>> of daemontools on Squeak boxes might be reconsidered. Not my decision, of
>> course, but as the topic came out, I thought I’d brain dump.
>> I want to like daemontools more than I find I’m able to.
>>
>> And on the topic of systemd, I’d say this, it’s a big leap. Back up
>> everything and review what you know about GRUB2. I’ve found that out the
>> hard way. I’m learning on a dedicated laptop and I lost my UI.
>> Couldn’t get it back. Could only get a terminal on tty1. So I created an
>> install stick and re-installed Ubuntu 14.04 from USB. Now I can try, fail,
>> and have a back up plan, learn more about GRUB2, systemd,
>> /etc/default/grub, systemctl, unit config files, etc. I don’t think
>> anybody would want that experience on a production box. It’s a dramatic
>> leap. Oh yea.
>>
>> Chris
>>
>>
>>       On Oct 21, 2014, at 7:27 AM, Levente Uzonyi <leves at elte.hu> wrote:
>>
>> Hi All,
>>
>> I tried to update my Squeak image today, and found that source.squeak.org
>> is down. On box2 I found that it's using all the cpu. Based on the
>> apachelogs it went down 7-8 hours ago.
>> I decided to restart it. svc -t didn't kill the image (nor did -k),
>> instead it spawned another image, so I stopped svc, killed the process
>> manually, and restarted it with svc.
>> The image is up now, but I wonder if there's anything else to do when a
>> SqueakSource image goes down.
>>
>> Levente
>>
>>
>>
>