[SOLVED] Certbot Apache error "Name duplicates previous WSGI daemon definition."

Certbot Apache error "Name duplicates previous WSGI daemon definition."

On my Ubuntu 16.04 server, I have an Apache conf file at /etc/apache2/sites-enabled/000-default.conf, which looks like this (abbreviated):

WSGIApplicationGroup %{GLOBAL}

<VirtualHost *:80>
    ServerName example.com
    WSGIDaemonProcess myprocess user=ubuntu group=ubuntu threads=10 home=/home/ubuntu/myapp
    WSGIProcessGroup myprocess
    ...
</VirtualHost>

It works fine in HTTP mode, but when I run $ sudo certbot --apache to set up HTTPS, it fails with the error Syntax error on line 7 of /etc/apache2/sites-enabled/000-default.conf: Name duplicates previous WSGI daemon definition. Line 7 is the line beginning with WSGIDaemonProcess.

Solution

It turns out that if my Apache conf file 000-default.conf only declares <VirtualHost *:80>...</VirtualHost>, then Certbot duplicates it and creates a second Apache conf file called 000-default-le-ssl.conf to define <VirtualHost *:443>...</VirtualHost>.

The Name duplicates previous WSGI daemon definition error appears because both Apache conf files have the same line defining WSGIDaemonProcess myprocess.... This appears to be a known Certbot bug.

The workaround I've found is to define both VirtualHosts (80 and 443) in the same Apache conf file (so that Certbot doesn't create a second file), and to define WSGIDaemonProcess outside both VirtualHosts, like this:

WSGIApplicationGroup %{GLOBAL}
WSGIDaemonProcess myprocess user=ubuntu group=ubuntu threads=10 home=/home/ubuntu/myapp
WSGIProcessGroup myprocess

<VirtualHost *:80>
    ServerName example.com
    ...
</VirtualHost>
<VirtualHost *:443>
    ServerName example.com
    ...
</VirtualHost>