No wget domain resolution in crontab

Question

I need to download a file when my computer boots up, so I created this line in my cronjob:

@reboot wget -a /log/here -O /save/here https://domain.tld/file.ext

Unfortunately, it creates a blank file at /save/here and gives me an error at /log/here.

The error says:

Resolving domain.tld (domain.tld)... failed: Temporary failure in name resolution.
wget: unable to resolve host address ■domain.tld■

Is this because name resolution isn't available so early in the boot process? Besides replacing the domain with an ip address bypassing name resolution, is there anything else I can do? I'd like to keep this all within the crontab.

Answer 1

Use a systemd unit file with dependency of network, or you can try this :

@reboot until ping -c1 dk &>/dev/null; do sleep 2; done; wget -a /log/here -O /save/here https://domain.tld/file.ext

(dk is the shortest domain name I know)

Answer 2

I found that the most reliable way to use wget at bootup was to create a job in /etc/rc.local. Also, as the computer I was using doesn't have an internal battery and instead relies on Network Time Protocol to set its clock on boot up, I found that I had to also specify the --no-check-certificate or not use https:// to prevent the command from failing due issues such as the SSL certificate not being valid yet.