[Ubuntu 18] systemd-resolve workaround

[Darleev]

Description

Bug fixing

• This is Github issue, with exactly the same problem, which was not fixed, only workaround was provided as solution.
• Root cause is unclear.
• I'm not sure that we can remove systemd-resolve without effects. but we can disable it by default. However, in this case, it is required to add manually nameserver record to /etc/resolv.conf file.
• In the official documentation, I didn't find misconfigurations.

So, the workaround helps us to resolve the issue with default systemd-resolve.

However, during the last try, we faced the issue with docker agents. I have verified that current workaround works as expected.

$ docker exec -it ubuntu:18 /bin/bash

Reproduced:

/# ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf
ln: failed to create symbolic link '/etc/resolv.conf': Device or resource busy

Current fix

/# if [[ -f /run/systemd/resolve/resolv.conf ]]; then
>     echo "Create resolv.conf link."
>     ln -sf /run/systemd/resolve/resolv.conf /etc/resolv.conf
> fi

works fine.

Related issue:

#819

Check list

• [+] Related issue / work item is attached
• Changes are tested and related VM images are successfully generated