Initializing shm:/var/xxxxxxx errno=13. Unable to start due to shared memory failure

You can generate a local policy module to allow this access. Do allow this access for now by executing:
# grep httpd /var/log/audit/audit.log | audit2allow -M mypol
# semodule -i mypol.pp

Apache proxy not working for a localhost port

ProxyPass / http://localhost:8983/
ProxyPassReverse / http://localhost:8983/

Above setting does not work.

To turn on this boolean you simple have to use this line (root permissions)

# setsebool -P httpd_can_network_connect on