Why are packages "kept back"?

Skaperen · 01-13-2010, 12:33 PM

Anyone know why these packages are "kept back"?

Code:

root@ubuntu:~# apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages have been kept back:
  bind9-host dnsutils libbind9-50 libdns50 libisc50 libisccc50 libisccfg50 liblwres50 linux-headers-server
  linux-image-server linux-server
0 upgraded, 0 newly installed, 0 to remove and 11 not upgraded.
root@ubuntu:~#

Skaperen · 01-13-2010, 03:04 PM

The command

Code:

apt-get dist-upgrade

got things upgraded. I'm not 100% sure it was right. And I still don't know why these files were kept back in the first place.

craigevil · 01-13-2010, 05:40 PM

From man apt-get

upgrade
upgrade is used to install the newest versions of all packages currently installed on the system from the sources enumerated in /etc/apt/sources.list. Packages currently installed with new versions available are retrieved and upgraded; under no circumstances are currently installed packages removed, or packages not already installed retrieved and installed. New versions of currently installed packages that cannot be upgraded without changing the install status of another package will be left at their current version. An update must be performed first so that apt-get knows that new versions of packages are available.

dist-upgrade
dist-upgrade in addition to performing the function of upgrade, also intelligently handles changing dependencies with new versions of packages; apt-get has a "smart" conflict resolution system, and it will attempt to upgrade the most important packages at the expense of less important ones if necessary. So, dist-upgrade command may remove some packages. The /etc/apt/sources.list file contains a list of locations from which to retrieve desired package files. See also apt_preferences(5) for a mechanism for overriding the general settings for individual packages.

Skaperen · 01-13-2010, 08:29 PM

All but 3 of the packages that were "kept back" already existed. They only needed to be upgraded. So apt-get doesn't even do an upgrade if that upgrade needs a new package? What if this is a security update?

What if I wanted to allow upgrades that add new dependencies for new packages to be installed, but not allow other kinds of changes to existing packages?

This seems to be something that could cause problems.

fragos · 01-14-2010, 03:37 PM

It may be that the new packages were referenced in the repositories but hadn't actually had their binary added yet. In the Update Manager this is sometimes cleared up with the "Check" button.