Get:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease [247 kB]
Get:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease [95.7 kB]
Get:3 http://mirrors.digitalocean.com/ubuntu xenial-security InRelease [94.5 kB]
Ign:1 http://mirrors.digitalocean.com/ubuntu xenial InRelease
Ign:2 http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease
Ign:3 http://mirrors.digitalocean.com/ubuntu xenial-security InRelease
Fetched 437 kB in 0s (4,252 kB/s)
Reading package lists... Done
W: GPG error: http://mirrors.digitalocean.com/ubuntu xenial InRelease: Could not execute 'apt-key' to verify signature (is gnupg installed?)
W: The repository 'http://mirrors.digitalocean.com/ubuntu xenial InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease: Could not execute 'apt-key' to verify signature (is gnupg installed?)
W: The repository 'http://mirrors.digitalocean.com/ubuntu xenial-updates InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://mirrors.digitalocean.com/ubuntu xenial-security InRelease: Could not execute 'apt-key' to verify signature (is gnupg installed?)
W: The repository 'http://mirrors.digitalocean.com/ubuntu xenial-security InRelease' is not signed.
N: Data from such a repository can't be authenticated and is therefore potentially dangerous to use.
N: See apt-secure(8) manpage for repository creation and user configuration details.