问如何在Ubuntu上安装cert/letsencypt？

EN

sudo add-apt-repository ppa:certbot/certbot
sudo apt-get update
sudo apt-get install python-certbot-nginx # doesn't exist

Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package python-certbot-nginx

$ sudo apt-get update
Hit:1 http:\\/\\/ppa.launchpad.net/certbot/certbot/ubuntu yakkety InRelease
0% [1 InRelease gpgv 24.3 kB] [Connecting to mirrors.digitalocean.com (198.199.99.226
Hit:3 https://deb.nodesource.com/node_6.x yakkety InRelease                          
Ign:2 http:\\/\\/packages.erlang-solutions.com/debian yakkety InRelease                  
Ign:5 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety InRelease                  
Hit:4 http:\\/\\/packages.erlang-solutions.com/debian yakkety Release                    
Ign:7 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-updates InRelease
Ign:8 http:\\/\\/security.ubuntu.com/ubuntu yakkety-security InRelease
Err:9 http:\\/\\/security.ubuntu.com/ubuntu yakkety-security Release
  404  Not Found [IP: 91.189.88.162 80]
Ign:10 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-backports InRelease
Err:11 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety Release
  404  Not Found
Err:12 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-updates Release
  404  Not Found
Err:13 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-backports Release
  404  Not Found
Reading package lists... Done
E: The repository 'http:\\/\\/security.ubuntu.com/ubuntu yakkety-security Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety-updates Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety-backports Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

$ 

$ sudo apt-get install software-properties-common

Reading package lists... Done
Building dependency tree       
Reading state information... Done
software-properties-common is already the newest version (0.96.24.7.2).
The following packages were automatically installed and are no longer required:
  python-acme python-certbot python-cffi-backend python-chardet
  python-configargparse python-configobj python-cryptography python-dialog
  python-enum34 python-funcsigs python-idna python-ipaddress python-mock
  python-ndg-httpsclient python-openssl python-parsedatetime python-pbr
  python-psutil python-pyasn1 python-pyicu python-requests python-rfc3339 python-six
  python-tz python-urllib3 python-zope.component python-zope.event
  python-zope.hookable python-zope.interface
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 1 not upgraded.

$ 

$ sudo add-apt-repository ppa:certbot/certbot

 This is the PPA for packages prepared by Debian Let's Encrypt Team and backported for Ubuntu(s).
 More info: https://launchpad.net/~certbot/+archive/ubuntu/certbot
Press [ENTER] to continue or ctrl-c to cancel adding it
gpg: keybox '/tmp/tmp53cbahkq/pubring.gpg' created
gpg: /tmp/tmp53cbahkq/trustdb.gpg: trustdb created
gpg: key 8C47BE8E75BCA694: public key "Launchpad PPA for certbot" imported
gpg: Total number processed: 1
gpg:               imported: 1
OK

$ $ sudo apt-get update
$: command not found

$ sudo apt-get update  
Hit:4 http:\\/\\/ppa.launchpad.net/certbot/certbot/ubuntu yakkety InRelease              
Ign:1 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety InRelease                  
Ign:2 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-updates InRelease          
Ign:3 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-backports InRelease        
Err:5 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety Release                    
  404  Not Found
Err:6 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-updates Release            
  404  Not Found
Err:7 http:\\/\\/lon1.mirrors.digitalocean.com/ubuntu yakkety-backports Release          
  404  Not Found
Ign:9 http:\\/\\/security.ubuntu.com/ubuntu yakkety-security InRelease                   
Hit:10 https://deb.nodesource.com/node_6.x yakkety InRelease                         
Ign:8 http:\\/\\/packages.erlang-solutions.com/debian yakkety InRelease       
Err:11 http:\\/\\/security.ubuntu.com/ubuntu yakkety-security Release         
  404  Not Found [IP: 91.189.91.23 80]
Hit:12 http:\\/\\/packages.erlang-solutions.com/debian yakkety Release
Reading package lists... Done
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety-updates Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/mirrors.digitalocean.com/ubuntu yakkety-backports Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http:\\/\\/security.ubuntu.com/ubuntu yakkety-security Release' does no longer have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.

$ sudo apt-get install python-certbot-nginx 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
E: Unable to locate package python-certbot-nginx