How to fix unbound.service warnings?

[Sun_Bear]

Please follow the below template, it will help us to help you!

Issue

I have installed pi-hole on a dedicated acer atom notebook x64 that is installed with ubuntu 24.04.01 server using command sudo curl -sSL https://install.pi-hole.net | bash per documentation. I have also installed unbound and have them both running. However, I noticed 3 warnings in unbound.service.

How do I rectify those warnings?

Expected Behaviour:

No unbound.service warnings.

Actual Behaviour:

Although Pihole and unbound are both running (can block ads and function as a recursive DNS), there are still three unbound.service warnings that I don't know how to fix.

Debug Token:

https://tricorder.pi-hole.net/GcDbA5uy/

[Sun_Bear]

The 2nd warning is due to line 58 of /etc/unbound/unbound.conf.d/pi-hole.conf:

# Ensure kernel buffer is large enough to not lose messages in traffic spikes
so-rcvbuf: 1m

I did not understand why the requested resource is not granted given that the system has available RAM.

master@atom:~$ free
               total        used        free      shared  buff/cache   available
Mem:         2003824      412480      809088        7512      955628     1591344
Swap:        2097148           0     2097148

I came across a similar question posted on AskUbuntu and tried its answer which worked. Below is what I did. The 2nd warning no longer appears.

[Bucking_Horn]

As those are unbound's warnings (and also, probably specific to your machine/OS), you should consider to consult unbound's documentation and support channels.

[Redback]

@Sun_Bear

/etc/unbound/unbound.conf.d/pi-hole.conf

Had the same problem with the second issue, with subnetcache: prefetch. Disable “prefetch: yes with prefetch: no”, in /etc/unbound/unbound.conf.d/pi-hole.conf, this will solve the issue with cache.

[stonerl]

@Redback

Disable “prefetch: yes with prefetch: no”,

This actually isn't the solution. Turn it back on to yes. If you cannot live with the warning, it does no harm, you need to disable the subnetcache module, which is enabled by default.

You can check which modules are enabled by executing this:

$ sudo unbound-control status
version: 1.17.1
verbosity: 0
threads: 2
modules: 3 [ subnetcache validator iterator ]
uptime: 253177 seconds
options: reuseport control(namedpipe)
unbound (pid 76437) is running...

Create a new file :

sudo touch /etc/unbound/unbound.conf.d/modules.conf

and add this content:

server:
    module-config: "validator iterator"

Next, restart unbound:

sudo systemctl restart unbound.service

and confirm that only those two modules are loaded:

$ sudo unbound-control status
version: 1.17.1
verbosity: 0
threads: 2
modules: 2 [ validator iterator ]
uptime: 531 seconds
options: reuseport control(namedpipe)
unbound (pid 80384) is running...

Now the warning won't show up anymore.

[Redback]

Thanks for the feedback. It works.

[Sun_Bear]

In short, you don't have to do anything for those warnings

The above is the answer by @gthess from unbound.

[stonerl]

Don't forget this part:

If you don't need subnetcache support you can explicitly set module-config: "validator iterator"

[Redback]

I have retracted my belief based on the limited information available at the time of my statement. Thank you for providing me with the link. It has greatly assisted me in comprehending errors in general.