bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Pierre Neidhardt]

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I've set up my desktop and laptop to use the new substitute discovery
feature, it's awesome!

However, when I put my desktop to sleep and run a Guix command on my
laptop that requires access to a sbustitute server, I see this:

--8<---------------cut here---------------start------------->8---
$ guix build ncdu
substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host
substitute: updating substitutes from 'http://ci.guix.gnu.org'... 100.0%
0.0 MB will be downloaded:
   /gnu/store/p70r4maqgh6ghl25h5a99w7sf1jidap8-ncdu-1.15.1
substituting /gnu/store/p70r4maqgh6ghl25h5a99w7sf1jidap8-ncdu-1.15.1...
--8<---------------cut here---------------end--------------->8---

The warning

--8<---------------cut here---------------start------------->8---
substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host
--8<---------------cut here---------------end--------------->8---

pops up on every download, which adds some 2s delay each time.  This
makes the whole process much slower.

For your information, Avahi does not find my desktop:

--8<---------------cut here---------------start------------->8---
$ sudo avahi-browse -al
Password: 
+ wlp2s0 IPv6 FOO___s MacBook Pro                        _companion-link._tcp local
+ wlp2s0 IPv4 FOO___s MacBook Pro                        _companion-link._tcp local
  C-c C-cGot SIGINT, quitting.
--8<---------------cut here---------------end--------------->8---

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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bug#45302: Acknowledgement (Avahi substitute discovery keeps trying to ping unaccessible servers)

[Pierre Neidhardt]

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I still witness this issue after restarting my laptop.
Looks like Avahi remembers the discovery across restarts.

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Maxim Cournoyer]

Hello,

Pierre Neidhardt <mail@ambrevar.xyz> writes:

> I've set up my desktop and laptop to use the new substitute discovery
> feature, it's awesome!
>
> However, when I put my desktop to sleep and run a Guix command on my
> laptop that requires access to a sbustitute server, I see this:
>
> $ guix build ncdu
> substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host
> substitute: updating substitutes from 'http://ci.guix.gnu.org'... 100.0%
> 0.0 MB will be downloaded:
>    /gnu/store/p70r4maqgh6ghl25h5a99w7sf1jidap8-ncdu-1.15.1
> substituting /gnu/store/p70r4maqgh6ghl25h5a99w7sf1jidap8-ncdu-1.15.1...
>
>
> The warning
>
> substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host
>
>
> pops up on every download, which adds some 2s delay each time.  This
> makes the whole process much slower.
>
> For your information, Avahi does not find my desktop:
>
> $ sudo avahi-browse -al
> Password: 
> + wlp2s0 IPv6 FOO___s MacBook Pro                        _companion-link._tcp local
> + wlp2s0 IPv4 FOO___s MacBook Pro                        _companion-link._tcp local
>   C-c C-cGot SIGINT, quitting.

This reminds me of https://issues.guix.gnu.org/30290.  Perhaps if we can
fix that one it'd make this one go away too?.  I was thinking of having
a simple mean to reduce the request attempts on servers down for a long
while, such as entering dead periods (breaks): "I've tried X times, it
doesn't respond, I give up for the next Y minutes"; allowing for X and Y
to be configured via the <guix-publish-configuration> record.

Do you think this would help?

Maxim

bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Pierre Neidhardt]

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Hi Maxim!

Thanks for the suggestion!
I'm a bit ignorant here, but my guess is that yes, it would help!

Cheers!

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Mathieu Othacehe]

Hello Pierre,

> I've set up my desktop and laptop to use the new substitute discovery
> feature, it's awesome!

Glad you like it, and sorry for the late answer.

> substitute: guix substitute: warning: 10.0.0.5: connection failed: No route to host

Once your laptop goes to sleep, Avahi should detect that the publish
service is gone and remove it from the cache at
/var/guix/discovery/publish.

I'm having troubles reproducing it at home. Could you please run
"avahi-browse -a" on your desktop, put your laptop to sleep, and check
if the publish server disappears this way:

--8<---------------cut here---------------start------------->8---
- enp7s0f0 IPv6 guix-publish-cervin                           _guix_publish._tcp   local
- enp7s0f0 IPv4 guix-publish-cervin                           _guix_publish._tcp   local
--8<---------------cut here---------------end--------------->8---

Regarding the reboot issue, that's because the cache wasn't cleaned-up,
it should by fixed with: ee94cd265e03d12eeeccf58cbaf74b90008fcd14.

Thanks,

Mathieu

bug#45302: Avahi substitute discovery keeps trying to ping unaccessible servers

[Pierre Neidhardt]

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Hi Mathieu,

sorry, didn't have much time to play with Guix recently.
All I can say is that I haven't experienced the issue lately.
I'm on commit c03875b0361f114634caeb54935fe37a9b7b05af.

I'll try the commands you suggested later.  Thanks for your time!

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