OpenStack Dashboard Installation Error – error processing package openstack-dashboard-ubuntu-theme [Solved]

While installing OpenStack Mitaka horizon module, I was stuck with an error processing package openstack-dashboard-ubuntu-theme. Below is the snapshot of the complete error message.

# apt-get install openstack-dashboard
Error:
apache2_invoke: Enable configuration openstack-dashboard.conf
apache2.service is not active, cannot reload.
invoke-rc.d: initscript apache2, action "reload" failed.
Setting up openstack-dashboard-ubuntu-theme (2:9.0.0-0ubuntu2.16.04.1) ...
dpkg: error processing package openstack-dashboard-ubuntu-theme (--configure):
 subprocess installed post-installation script returned error exit status 1

The error indicates that the Apache web server is not active and seems like that’s the reason for openstack-dashboard-ubuntu-theme processing package error. If you ever stuck with this error, then here’s how you can fix it.

Solution:

The first thing I did was to confirm whether the Apache web sever is active and as the error message suggested, the web server failed to start. The Apache error logs hinted that another service is listening on port 5000 and it was nothing but the Keystone python program. During the Keystone installation, I remembered configuring the service by creating a virtual host in Apache and it means, the keystone service should start along with the web server. So I disabled keystone service to allow web server to start smoothly.

# /etc/init.d/keystone stop

# /etc/init.d/apache2 start

Now execute the below command to remove the openstack-dashboard-ubuntu-theme (this package will be installed only on Ubuntu)

apt-get remove --purge openstack-dashboard-ubuntu-theme

or use

dpkg --remove --force-remove-reinstreq openstack-dashboard-ubuntu-theme

That’s it, now install openstack-dashboard and it should work.

# apt-get install openstack-dashboard

Reference.