Estou passando por um problema semelhante a este no servidor GNS3.
Começa com propriedades de software comuns a python3-pycurl, que não é instalável e não pode ser encontrado com apt-cache search .
gns3@gns3vm:~$ uname -a
Linux gns3vm 4.4.0-31-generic #50~14.04.1-Ubuntu SMP Wed Jul 13 01:07:32 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux
gns3@gns3vm:~$ sudo apt-get upgrade software-properties-common
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
software-properties-common : Depends: python3-software-properties (= 0.92.37.8) but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
gns3@gns3vm:~$ sudo apt-get upgrade python3-software-properties
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
python3-software-properties : Depends: python3-pycurl but it is not installable
E: Unable to correct problems, you have held broken packages.
gns3@gns3vm:~$ sudo apt-cache search python3-software-proper
python3-software-properties - manage the repositories that you install software from
gns3@gns3vm:~$
gns3@gns3vm:~$
gns3@gns3vm:~$ sudo apt-get upgrade python3-pycurl
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
Package python3-pycurl is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'python3-pycurl' has no installation candidate
gns3@gns3vm:~$
Tags apt dependencies