Name

docker-centos7-systemd-perl-starman-psgi - Dockerfile for Starman PSGI server running on CentOS7 under Systemd

Docker Image

This Docker image is built from the Official CentOS 7 Docker Image.

Systemd

The docker image uses the Systemd configuration from https://hub.docker.com/_/centos#Systemd+integration

Starman

Starman is a high-performance preforking PSGI/Plack web server. We install it with yum from RPMs at OpenFusion

Systemd Unit File

The Starman Systemd Unit File is installed by the Dockerfile as /usr/lib/systemd/system/starman.service and then enabled with systemctl. Starman is configured to run 3 workers and to listen on port 80 (this port must match the Dockerfile exposed port).

PSGI App

The PSGI App app.psgi is saved inside the Docker image as /app/app.psgi. This path is hard coded in the service file.

PSGI App Dependencies

Dependencies to run the PSGI app inside the container must be installed in the Dockerfile. We install three dependencies for our example PSGI program one from the CentOS 7 base repository and two from the DavisNetworks.com repository.

• DateTime
• Plack::Middleware::Expires
• Plack::Middleware::Session::Cookie

Docker Build Command

$ sudo docker build --rm --tag=local/centos7-systemd-perl-starman-psgi .

• --rm - Remove intermediate containers after a successful build.

Docker Run Command

$ sudo docker run --detach --name starman --tmpfs /run --volume=/sys/fs/cgroup:/sys/fs/cgroup:ro --publish 5000:80 local/centos7-systemd-perl-starman-psgi

• --detach - Detached mode: run the container in the background and print the new container ID. (run as -ti to see more information for debugging)
• --tmpfs - required setting for CentOS 7 with Systemd
• --volume - required volume setting for CentOS 7 with Systemd
• --publish - Publish a container's port, or range of ports, to the host - [host]:[container]

See Also

• CentOS7-Systemd-Mojolicious