2 Zář
2019
2 Zář
'19
11:46
Hello,
Could someone help me to understand the behavior of Knot Resolver?
Can I somehow process a change in the list of static records for knot
resolver like a command for reloading configuration?
If I have in the kresd.conf file a module
modules = {
'hints> iterate', - Add static records to resolver
...
...
and the list is located
- Load static records
hints.add_hosts ('/ etc / knot-resolver / static_records.txt')
how can I reload the change in the static_records.txt list for the kresd @ 1
service
Or should I always restart the daemon kresd @ 1
systemctl restart Kresd @ 1
Thanks for any advice,
Regadrs,
--
Smil Milan Jeskyňka Kazatel
2 Zář
2 Zář
12:51
Hello,
On 02. 09. 19 11:46, Milan Jeskynka Kazatel wrote:
Hello,
Could someone help me to understand the behavior of Knot Resolver?
Can I somehow process a change in the list of static records for knot
resolver like a command for reloading configuration?
If I have in the kresd.conf file a module
modules = {
'hints> iterate', - Add static records to resolver
...
...
and the list is located
- Load static records
hints.add_hosts ('/ etc / knot-resolver / static_records.txt')
how can I reload the change in the static_records.txt list for the kresd
@ 1 service
Or should I always restart the daemon kresd @ 1
systemctl restart Kresd @ 1
Here are multiple options:
a) If you do not require zero-downtime then you can simply restart
kresd@1 instance:
systemctl restart kresd@1
b) If you require zero-downtime and have only single kresd instance you
can do this:
systemctl start kresd@2
systemctl restart kresd@1
systemctl stop kresd@2
Please note the numbers at the end!
These commands start second (temporary) Knot Resolver instance with new
config and then restart the old instance with old config. During restart
the second instance will handle incomming DNS queries. After this
exercise the second instance is not needed and can be stopped.
c) If you require zero-downtime and have more than one kresd instance
you can simply restart instances one after the other:
systemctl restart kresd@1
systemctl restart kresd@2
systemctl restart kresd@3
...
In general we recommend having at least two instances running because it
allows to handle fatal errors (like crash) by automatic restart - and
clients will likely not notice anything.
I hope it helps.
--
Petr Špaček @ CZ.NIC
12:52
Hello.
On 9/2/19 11:46 AM, Milan Jeskynka Kazatel wrote:
Can I somehow process a change in the list of static
records for knot
resolver like a command for reloading configuration?
In this particular case there's also a command that clears the hints and
(optionally) loads a file:
https://knot-resolver.readthedocs.io/en/stable/modules.html#c.hints.config
You can run commands by attaching to the control socket, e.g. echo
"command" | nc -U /run/knot-resolver/control@1
--Vladimir
15:00
Hello Vladimir,
if I understand your hint correctly, then I should change in the config file
a variable from hints.add_hosts([path]) to hints.config([path]) because it
does the same things + reload hints.
"Clear any configured hints, and optionally load a hosts-like file as in
hints.add_hosts(path). (Root hints are not touched.)"
Could you please more specify the "command" how to in the script attach it
to the control socket? You mention a echo.
Anyway, the hint from Petr Spacek sounds good for my case.
***
If you require zero-downtime and have only single kresd instance you
can do this:
systemctl start kresd@2
systemctl restart kresd@1
systemctl stop kresd@2
Please note the numbers at the end!
***
I need to know what option is more suggested and supports daemon-reload in
the case when the option is missing.
Why is not exists so simply command like "systemctl reload kresd@1"
Thank you for your time and advice.
--
Smil Milan Jeskyňka Kazatel
---------- Původní e-mail ----------
Od: Vladimír Čunát <vladimir.cunat(a)nic.cz>
Komu: Milan Jeskynka Kazatel <KazatelM(a)seznam.cz>
Datum: 2. 9. 2019 12:52:47
Předmět: Re: [knot-resolver-users] Knot Resolver - module hints - reload?
"Hello.
On 9/2/19 11:46 AM, Milan Jeskynka Kazatel wrote:
Can I somehow process a change in the list of static
records for knot
resolver like a command for reloading configuration?
In this particular case there's also a command that clears the hints and
(optionally) loads a file:
https://knot-resolver.readthedocs.io/en/stable/modules.html#c.hints.config
You can run commands by attaching to the control socket, e.g. echo
"command" | nc -U /run/knot-resolver/control@1
--Vladimir
"
15:10
On 9/2/19 3:00 PM, Milan Jeskynka Kazatel wrote:
if I understand your hint correctly, then I should
change in the
config file a variable from hints.add_hosts([path])
to hints.config([path]) because it does the same things + reload hints.
No, changing the config isn't needed (and won't help). The hints.config
command clears all hints and loads new ones from a file. Let me write a
more explicit example doing the reload:
echo "hints.config('/etc/hosts')" | sudo nc -U
/run/knot-resolver/control@1
--Vladimir
5 Zář
5 Zář
11:37
Hello Vladimir,
many thanks for your explanation regarding your meaning of command with
using control@1. But I'm failed.
Unfortunately, I'm using now version Knot DNS Resolver, version 2.3.0 (I
really want to upgrade it later) trough a systemd with module HTTP on Centos
7.
For me, the kresd does not create any control@1 nowhere, then I´m not able
to use **echo "hints.config('/etc/hosts')" | sudo nc -U
/run/knot-resolver/
control@1**
And unfortunately, my second option with two instances of kresd@1 and kresd@
2, mentioned by Petr Špaček @ CZ.NIC, failed because my HTTP address and
port are already in use.
Any other option how silently do a "reload" hints. in the case when is a
record in this file changed?
thanks,
--
Smil Milan Jeskyňka Kazatel
---------- Původní e-mail ----------
Od: Vladimír Čunát <vladimir.cunat(a)nic.cz>
Komu: Milan Jeskynka Kazatel <KazatelM(a)seznam.cz>
Datum: 2. 9. 2019 15:10:44
Předmět: Re: [knot-resolver-users] Knot Resolver - module hints - reload?
"On 9/2/19 3:00 PM, Milan Jeskynka Kazatel wrote:
if I understand your hint correctly, then I should
change in the
config file a variable from hints.add_hosts([path])
to hints.config([path]) because it does the same things + reload hints.
No, changing the config isn't needed (and won't help). The hints.config
command clears all hints and loads new ones from a file. Let me write a
more explicit example doing the reload:
echo "hints.config('/etc/hosts')" | sudo nc -U
/run/knot-resolver/control@1
--Vladimir
"
12:45
On 9/5/19 11:37 AM, Milan Jeskynka Kazatel wrote:
Unfortunately, I'm using now version Knot DNS
Resolver, version 2.3.0
(I really want to upgrade it later) trough a systemd with module HTTP
on Centos 7.
For me, the kresd does not create any control@1 nowhere, then I´m not
able to use **echo "hints.config('/etc/hosts')" | sudo nc -U
/run/knot-resolver/control@1**
Oh, for CentOS the packaging is a bit different than elsewhere. I think
the control socket is located in /var/cache/knot-resolver/tty/$PID - at
least in the current 4.2.0 - anyway, if you find that file, it should
work the same even for 2.3.0.
And unfortunately, my second option with two instances
of kresd@1 and
kresd@2, mentioned by Petr Špaček @ CZ.NIC, failed because my HTTP
address and port are already in use.
I think this particular problem was solved in 4.0.0
Any other option how silently do a "reload"
hints. in the case when is
a record in this file changed?
Restarting the service is probably best in your
current situation. The
cache is kept, so it should be cheap (and easy!).
--Vladimir
16:01
Hello Vladimir,
many thanks,
the /var/cache/knot-resolver/tty/$PID works fine.
Regards.
--
Smil Milan Jeskyňka Kazatel
---------- Původní e-mail ----------
Od: Vladimír Čunát <vladimir.cunat(a)nic.cz>
Komu: Milan Jeskynka Kazatel <KazatelM(a)seznam.cz>
Datum: 5. 9. 2019 12:45:12
Předmět: Re: [knot-resolver-users] Knot Resolver - module hints - reload?
"On 9/5/19 11:37 AM, Milan Jeskynka Kazatel wrote:
Unfortunately, I'm using now version Knot DNS
Resolver, version 2.3.0
(I really want to upgrade it later) trough a systemd with module HTTP
on Centos 7.
For me, the kresd does not create any control@1 nowhere, then I´m not
able to use **echo "hints.config('/etc/hosts')" | sudo nc -U
/run/knot-resolver/control@1**
Oh, for CentOS the packaging is a bit different than elsewhere. I think
the control socket is located in /var/cache/knot-resolver/tty/$PID - at
least in the current 4.2.0 - anyway, if you find that file, it should
work the same even for 2.3.0.
And unfortunately, my second option with two instances
of kresd@1 and
kresd@2, mentioned by Petr Špaček @ CZ.NIC, failed because my HTTP
address and port are already in use.
I think this particular problem was solved in 4.0.0
Any other option how silently do a "reload"
hints. in the case when is
a record in this file changed?
Restarting the service is probably best in your
current situation. The
cache is kept, so it should be cheap (and easy!).
--Vladimir
"
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days inactive
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knot-resolver-users@lists.nic.cz
7 comments
3 participants
participants (3)
-
Milan Jeskynka Kazatel -
Petr Špaček -
Vladimír Čunát