Hello Thomas,
Shibboleth service is being installed separately from gluu-server. So gluu-server rebooting have nothing to do with shibboleth service startup.
You should install gluu-server and shibboleth service separately and then configure each one to work together.
1. To install the Shibboleth SP on ubuntu, run the following commands in a terminal:
```
apt-get install apache2 libshibsp6 libapache2-mod-shib2
a2enmod cgi
a2enmod ssl
a2enmod shib2
a2ensite default-ssl
mkdir /etc/certs
cd /etc/certs
openssl genrsa -des3 -out sp.key 2048
openssl rsa -in sp.key -out sp.key.insecure
mv sp.key.insecure sp.key
openssl req -new -key sp.key -out sp.csr
openssl x509 -req -days 365 -in sp.csr -signkey sp.key -out sp.crt
shib-metagen -c /etc/certs/sp.crt -h sp.gluu.info > /etc/shibboleth/SP-metadata.xml
service apache2 start
service shibd start
```
2. Then you need to configure gluu-server and create a Trust Relationship in your Gluu Server. For this step please follow this guide.
https://gluu.org/docs/ce/3.1.3/integration/sswebapps/saml-sp/#super-quick-ubuntu-shib-apache-install
Please ask any questions you have, I am happy to guide you through configuration process.
Thanks,
Davit