Prefer IPv4 for zypper updates

I had been battling server timeouts from a local mirror of OpenSUSE repositories when I noticed that if I telneted to the troublesome server it attempted to contact it via its IPv6 address. My Internet retailer doesn't support IPv6 connections, although my Linux distro and modem are capable. At the moment there's no need as there is no shortage of IPv4 addresses in this country.

A little search found that it's due to the curl library trying IPv6 addresses first. There is a little known environment variable in libzypp to control this. I put

ZYPP_MEDIA_CURL_IPRESOLVE=4

in my environment settings and I no longer had server timeouts.

If you are using sudo to run zypper, look into the env_keep option  in the sudoers file, and check that the env_reset option is enabled (the default), for example:

Defaults env_keep += "ZYPP_MEDIA_CURL_IPRESOLVE"

 

Downloading updates to openSUSE during off-peak times using zypper

You might, like me, have an ISP that has peak and off-peak quotas. I prefer to consume off-peak quota whenever possible to leave more for waking hours.


My openSUSE installation gets regular package updates. Since I want every update in any case I looked for a way to download the packages ahead of time during off-peak. It turned out to be quite easy, as root I just created a file in /etc/cron.d/zypper-offpeak containing one line:



6 6 * * * root zypper -n up -l -d > /dev/null 2>&1


See man crontab for an explanation of the fields. This runs at 0606 in the morning. The -n allows it to run non-interactively, the -l auto-agrees with licenses (usually Adobe Reader plugin), and -d is the magic, meaning download only.


The packages go into the normal package cache, and next time you do a zypper up, they will install straight away. This makes for faster updates and the savings can be considerable for kernel-source and VirtualBox packages.


This has already been blogged here citing a different motivation. The correct answer is in one of the comments, apparently -d or --download-only was not in old versions of zypper.