Need epel-release package installed.

sudo yum install php php-pgsql php-mbstring php-fpm postgresql-server postgresql

Database Server

In the trial environment I am using postgresql on the VM

sudo postgresql-setup initdb
sudo systemctl enable postgresql
sudo systemctl start postgresql

Setup the postgres password

$ sudo passwd postgres
# enter new password
$ su - postgres
$ psql
postgres=# \password
# enter same password
postgres=# \q
$ exit

As the postgres user also modify /var/lib/pgsql/data/pg_hba.conf to set md5 method for all IPv4 local connections.

host all all md5

Mantis Install

Grab the source

curl -O ""

Make a /srv/www directory and extract the contents into a folder mantisbt .

semanage fcontext -a -t httpd_sys_content_t "/srv/www(/.*)?"
restorecon -R -v /srv/www

Caddy Install

Grab the tarball

curl -O caddy.tar.gz ""

Follow the installation instructions in caddy/dist/init/linux-systemd at master · mholt/caddy · GitHub to enable systemd support, substituting /var/www for /srv/www .

The /etc/caddy/Caddyfile is as simple as:
root /srv/www/mantisbt
fastcgi / php
log stdout

Allow web server to connect to database.

sudo setsebool -P httpd_can_network_connect_db on

Enable firewall rule

sudo firewall-cmd --zone=public --add-port=8080/tcp --permanent
sudo firewall-cmd --reload

Configure PHP-FPM

By default php-fpm is configured to use the apache user on CentOS. Caddy and the mantisbt files use www-data so update this in /etc/php-fpm.d/www.conf by changing the user and group directives.