@teiszler,
apt-get upgrade is successful as below:
apt-get upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages have been kept back:
apache2 apache2-bin apache2-data
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
The problem is with it returns some errors as below.
# apt-get update
Err http://ubuntu-cloud.archive.canonical.com trusty-updates/kilo InRelease
Err http://ubuntu-cloud.archive.canonical.com trusty-updates/kilo Release.gpg
Could not resolve 'ubuntu-cloud.archive.canonical.com'
Err http://ug.archive.ubuntu.com trusty InRelease
Err http://ug.archive.ubuntu.com trusty-updates InRelease
Err http://ug.archive.ubuntu.com trusty-backports InRelease
Err http://ug.archive.ubuntu.com trusty Release.gpg
Could not resolve 'ug.archive.ubuntu.com'
Err http://ug.archive.ubuntu.com trusty-updates Release.gpg
Could not resolve 'ug.archive.ubuntu.com'
Err http://ug.archive.ubuntu.com trusty-backports Release.gpg
Could not resolve 'ug.archive.ubuntu.com'
Err http://ppa.launchpad.net trusty InRelease
Err http://ppa.launchpad.net trusty Release.gpg
Could not resolve 'ppa.launchpad.net'
Err http://security.ubuntu.com trusty-security InRelease
Err http://security.ubuntu.com trusty-security Release.gpg
Could not resolve 'security.ubuntu.com'
Reading package lists... Done
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty/InRelease
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty-updates/InRelease
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty-backports/InRelease
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/InRelease
W: Failed to fetch http://ppa.launchpad.net/ansible/ansible/ubuntu/dists/trusty/InRelease
W: Failed to fetch http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/trusty-updates/kilo/InRelease
W: Failed to fetch http://ubuntu-cloud.archive.canonical.com/ubuntu/dists/trusty-updates/kilo/Release.gpg Could not resolve 'ubuntu-cloud.archive.canonical.com'
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty/Release.gpg Could not resolve 'ug.archive.ubuntu.com'
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty-updates/Release.gpg Could not resolve 'ug.archive.ubuntu.com'
W: Failed to fetch http://ug.archive.ubuntu.com/ubuntu/dists/trusty-backports/Release.gpg Could not resolve 'ug.archive.ubuntu.com'
W: Failed to fetch http://ppa.launchpad.net/ansible/ansible/ubuntu/dists/trusty/Release.gpg Could not resolve 'ppa.launchpad.net'
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/trusty-security/Release.gpg Could not resolve 'security.ubuntu.com'
W: Some index files failed to download. They have been ignored, or old ones used instead.