O Docker não instala no Ubuntu 14.04 devido a problemas no Postgresql?

Question

Estou executando o Ubuntu 14.04 LTS. Quando tento instalar o docker nele, recebo os seguintes erros. Eu tive esses erros antes. Eles começaram quando eu atualizei para o PostgreSQL e de alguma forma a versão 9.3 ainda está por aí. No entanto, eu instalei vários pacotes com apt-get depois que os erros começaram a acontecer e os erros nunca pareciam afetar a instalação.

Como posso instalar o docker? As mensagens de erro do PostgreSQL estão realmente prejudicando alguma coisa ou são irrelevantes?

Aqui está um dump da tentativa de instalação do docker:

$ sudo apt-get install docker

Reading package lists... Done
Building dependency tree       
Reading state information... Done
docker is already the newest version.
The following packages were automatically installed and are no longer required:
  libclang-common-3.4-dev libclang1-3.4 linux-headers-4.4.0-31
  linux-headers-4.4.0-31-generic linux-image-4.4.0-31-generic
  linux-image-extra-4.4.0-31-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.
5 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] Y
Setting up postgresql-common (189.pgdg14.04+1) ...
 * Starting PostgreSQL 9.3 database server                                                                                                    * Failed to issue method call: Unit [email protected] failed to load: No such file or directory. See system logs and 'systemctl status [email protected]' for details.
                                                                                                                                  [fail]
 * Starting PostgreSQL 9.4 database server                                                                                                    * Failed to issue method call: Unit [email protected] failed to load: No such file or directory. See system logs and 'systemctl status [email protected]' for details.
                                                                                                                                  [fail]
invoke-rc.d: initscript postgresql, action "start" failed.
dpkg: error processing package postgresql-common (--configure):
 subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of postgresql-9.3:
 postgresql-9.3 depends on postgresql-common (>= 142~); however:
  Package postgresql-common is not configured yet.

dpkg: error processing package postgresql-9.3 (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of postgresql-9.4:
 postgresql-9.4 depends on postgresql-common (>= 142~); however:
  Package postgresql-common is not configured yet.

dpkg: error processing package postgresql-9.4 (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of postgresql-contrib-9.3:
 postgresql-contrib-9.3 depends on postgresql-9.3 (= 9.3.20-1.pgdg14.04+1); however:
  Package postgresql-9.3 is not configured yet.

dpkg: error processing package postgresql-contrib-9.3 (--configure):
 dependency problems - leaving unconfigured
dpkg: dependency problems prevent configuration of postgresql-contrib-9.4:
 postgresql-contrib-9.4 dependNo apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                                                    No apport report written because the error message indicates its a followup error from a previous failure.
                                                                                                 No apport report written because MaxReports is reached already
                  No apport report written because MaxReports is reached already
                                                                                s on postgresql-9.4 (= 9.4.15-1.pgdg14.04+1); however:
  Package postgresql-9.4 is not configured yet.

dpkg: error processing package postgresql-contrib-9.4 (--configure):
 dependency problems - leaving unconfigured
Errors were encountered while processing:
 postgresql-common
 postgresql-9.3
 postgresql-9.4
 postgresql-contrib-9.3
 postgresql-contrib-9.4
E: Sub-process /usr/bin/dpkg returned an error code (1)