Failed to start systemd-resolved.service . systemd-resolved.service: Failed with result 'resources'. [1]: Failed to start Network Name Resolution

Question

Main Issue is:

# systemctl status systemd-resolved.service

systemd-resolved.service -
Network Name Resolution Loaded: loaded (/lib/systemd/system/systemd-resolved.service; enabled; vendor preset: enabled)
Active: failed (Result: resources) since Wed 2021-05-19 11:15:15 UTC; 23s ago
Docs: man:systemd-resolved.service(8)
https://www.freedesktop.org/wiki/Software/systemd/resolved
https://www.freedesktop.org/wiki/Software/systemd/writing-network-configuration-managers
https://www.freedesktop.org/wiki/Software/systemd/writing-resolver-clients

May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Service has no hold-off time, scheduling restart.
May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Scheduled restart job, restart counter is at 5.
May 19 11:15:15 kv-server systemd[1]: Stopped Network Name Resolution.
May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Start request repeated too quickly.
May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Failed with result 'resources'.
May 19 11:15:15 kv-server systemd[1]: Failed to start Network Name Resolution.

This issue was something which I landed up by doing the below steps:

apt-get update was failing. I started by following the answer of https://askubuntu.com/a/91590/1042537

This explained the issue and pointed fault towards DNS.

To configure dns servers, I followed https://stackoverflow.com/a/54460886/14950576 .

I also did # chattr +i /etc/resolv.conf so that resolv.conf doesn't get updated by DHCP

I tried # ping google.com but it still failed.

I observed a bad symlink /etc/resolv.conf -> /run/systemd/resolve/stub-resolve.conf So I tried to access /run/systemd/resolve/stub-resolve.conf

Got an error that there is no directory /run/systemd/resolve

So I followed https://unix.stackexchange.com/a/613143 and got to know that systemd-resolved.service was not running.

Error I got was

# systemctl enable --now systemd-resolved.service
Job for systemd-resolved.service failed because of unavailable resources or another system error.
See "systemctl status systemd-resolved.service" and "journalctl -xe" for details.

As I tried to do start that, I ran into the main issue.

So Network Name Resolution is unable to start.

Solution

I am a novice contributor. Would like suggetions to improve the answer !!

Although a lot of errors are raised by #systemctl status systemd-resolved.service The main issue was resources.

This issue was caused by the absence of tmp directory in var

i.e. /var/tmp/ was absent.

Solution:

mkdir /var/tmp
chmod 777 /var/tmp

777 permission is a bad practice for webservers as it gives read/write access to every user. So please use it accordingly

Then to start the service, I performed:

systemctl enable --now systemd-resolved.service

Then, ping google.com gives successful result.

Solution was inspired from https://www.raspberrypi.org/forums/viewtopic.php?t=249619

PS: For other errors:

May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Service has no hold-off time, scheduling restart.
May 19 11:15:15 kv-server systemd[1]: systemd-resolved.service: Scheduled restart job, restart counter is at 5.

You can view https://serverfault.com/a/1032451

For good resources on systemd-resolved name resolution view:

https://www.youtube.com/watch?v=DtFjrJdnWAU

https://moss.sh/name-resolution-issue-systemd-resolved/

https://unix.stackexchange.com/questions/328131/how-to-troubleshoot-dns-with-systemd-resolved