склонная человечность 14.04 - получает обновление, не работающее

Когда я вхожу в систему мой docker-machine (который размещается с digitalocean), я вижу следующее сообщение:

62 packages can be updated.
28 updates are security updates.

все же каждый раз, когда я пытаюсь работать apt-get update, Я получаю следующее:

root@alexus:~# apt-get update
Ign http://security.ubuntu.com trusty-security InRelease
Hit http://security.ubuntu.com trusty-security Release.gpg 
Hit http://security.ubuntu.com trusty-security Release     
Hit http://security.ubuntu.com trusty-security/main Sources                    
Hit http://security.ubuntu.com trusty-security/universe Sources 
Hit http://security.ubuntu.com trusty-security/main amd64 Packages
Hit http://security.ubuntu.com trusty-security/universe amd64 Packages
Hit http://security.ubuntu.com trusty-security/main i386 Packages
Hit http://security.ubuntu.com trusty-security/universe i386 Packages
Hit http://security.ubuntu.com trusty-security/main Translation-en  
Hit http://security.ubuntu.com trusty-security/universe Translation-en
Ign http://mirrors.digitalocean.com trusty InRelease
Ign http://mirrors.digitalocean.com trusty-updates InRelease        
Hit http://mirrors.digitalocean.com trusty Release.gpg              
Get:1 https://apt.dockerproject.org ubuntu-trusty InRelease
Ign https://apt.dockerproject.org ubuntu-trusty InRelease       
Hit https://apt.dockerproject.org ubuntu-trusty Release.gpg     
Hit https://apt.dockerproject.org ubuntu-trusty Release
Hit https://apt.dockerproject.org ubuntu-trusty/main amd64 Packages        
Hit https://apt.dockerproject.org ubuntu-trusty/main i386 Packages
Get:2 http://mirrors.digitalocean.com trusty-updates Release.gpg [933 B]
Get:3 https://apt.dockerproject.org ubuntu-trusty/main Translation-en_US       
Hit http://mirrors.digitalocean.com trusty Release    
Ign https://apt.dockerproject.org ubuntu-trusty/main Translation-en_US
Ign https://apt.dockerproject.org ubuntu-trusty/main Translation-en
Get:4 http://mirrors.digitalocean.com trusty-updates Release [63.5 kB]
Hit http://mirrors.digitalocean.com trusty/main Sources  
Hit http://mirrors.digitalocean.com trusty/universe Sources
Hit http://mirrors.digitalocean.com trusty/main amd64 Packages
Hit http://mirrors.digitalocean.com trusty/universe amd64 Packages
Hit http://mirrors.digitalocean.com trusty/main i386 Packages
Hit http://mirrors.digitalocean.com trusty/universe i386 Packages
Hit http://mirrors.digitalocean.com trusty/main Translation-en
Hit http://mirrors.digitalocean.com trusty/universe Translation-en
Get:5 http://mirrors.digitalocean.com trusty-updates/main Sources [237 kB]
Get:6 http://mirrors.digitalocean.com trusty-updates/universe Sources [139 kB]
Get:7 http://mirrors.digitalocean.com trusty-updates/main amd64 Packages [627 kB]
Get:8 http://mirrors.digitalocean.com trusty-updates/universe amd64 Packages [320 kB]
Get:9 http://mirrors.digitalocean.com trusty-updates/main i386 Packages [608 kB]
Get:10 http://mirrors.digitalocean.com trusty-updates/universe i386 Packages [320 kB]
Hit http://mirrors.digitalocean.com trusty-updates/main Translation-en         
Hit http://mirrors.digitalocean.com trusty-updates/universe Translation-en
Ign http://mirrors.digitalocean.com trusty/main Translation-en_US   
Ign http://mirrors.digitalocean.com trusty/universe Translation-en_US
Fetched 2,316 kB in 4s (513 kB/s)               
Reading package lists... Done
root@alexus:~# 

ОС моей системы и ядро:

root@alexus:~# cat /etc/issue.net 
Ubuntu 14.04.3 LTS
root@alexus:~# uname -a
Linux alexus 3.13.0-57-generic #95-Ubuntu SMP Fri Jun 19 09:28:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux
root@alexus:~# 

Как я обновляю свою систему?