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README.md

Apache HTTP Server 2.4 Container Image

This container image includes Apache HTTP Server 2.4 for OpenShift and general usage. Users can choose between RHEL, CentOS and Fedora based images. The RHEL image is available in the Red Hat Container Catalog as registry.access.redhat.com/rhscl/httpd-24-rhel7. The CentOS image is then available on Docker Hub as centos/httpd-24-centos7.

Description

Apache HTTP Server 2.4 available as container, is a powerful, efficient, and extensible web server. Apache supports a variety of features, many implemented as compiled modules which extend the core functionality. These can range from server-side programming language support to authentication schemes. Virtual hosting allows one Apache installation to serve many different Web sites."

Usage

For this, we will assume that you are using the Apache HTTP Server 2.4 container image from the Red Hat Container Catalog called rhscl/httpd-24-rhel7. The image can be used as a base image for other applications based on Apache HTTP web server.

An example of the data on the host for both the examples above, that will be served by Apache HTTP web server:

$ ls -lZ /wwwdata/html
-rw-r--r--. 1 1001 1001 54321 Jan 01 12:34 index.html
-rw-r--r--. 1 1001 1001  5678 Jan 01 12:34 page.html

If you want to run the image and mount the static pages available in /wwwdata on the host as a container volume, execute the following command:

$ docker run -d --name httpd -p 8080:8080 -v /wwwdata:/var/www:Z rhscl/httpd-24-rhel7

This will create a container named httpd running Apache HTTP Server, serving data from /wwwdata directory. Port 8080 will be exposed and mapped to the host.

If you want to create a new container layered image, use Source-to-Image, a tool for building/building artifacts from source and injecting into container images. To create a new container image named httpd-app using Source-to-Image, while using data available in /wwwdata on the host, execute the following command:

$ s2i build file:///wwwdata/html rhscl/httpd-24-rhel7 httpd-app

To run such a new image, execute the following command:

$ docker run -d --name httpd -p 8080:8080 httpd-app

The structure of httpd-app can look like this:

./httpd-cfg
Can contain additional Apache configuration files (*.conf)

./httpd-pre-init
Can contain shell scripts (*.sh) that are sourced before httpd is started

./httpd-ssl
Can contain own SSL certificate (in certs/ subdirectory) and key (in private/ subdirectory)

./
Application source code

Environment variables and volumes

The Apache HTTP Server container image supports the following configuration variable, which can be set by using the -e option with the docker run command:

HTTPD_LOG_TO_VOLUME
By default, httpd logs into standard output, so the logs are accessible by using the docker logs command. When HTTPD_LOG_TO_VOLUME is set, httpd logs into /var/log/httpd24, which can be mounted to host system using the container volumes. This option is only allowed when container is run as UID 0.

HTTPD_MPM The variable HTTPD_MPM can be set to change the default Multi-Processing Module (MPM) from the package default MPM.

If you want to run the image and mount the log files into /wwwlogs on the host as a container volume, execute the following command:

$ docker run -d -u 0 -e HTTPD_LOG_TO_VOLUME=1 --name httpd -v /wwwlogs:/var/log/httpd24:Z rhscl/httpd-24-rhel7

To run an image using the event MPM (rather than the default prefork), execute the following command:

$ docker run -d -e HTTPD_MPM=event --name httpd rhscl/httpd-24-rhel7

You can also set the following mount points by passing the -v /host:/container flag to Docker.

/var/www
Apache HTTP Server data directory

/var/log/httpd24
Apache HTTP Server log directory (available only when running as root, path /var/log/httpd is used in case of Fedora based image)

Notice: When mouting a directory from the host into the container, ensure that the mounted directory has the appropriate permissions and that the owner and group of the directory matches the user UID or name which is running inside the container.

Using own SSL certificates

In order to provide own SSL certificates for securing the connection with SSL, use the extending feature described above. In particular, put the SSL certificates into a separate directory inside your application:

./httpd-ssl/certs/server-cert-selfsigned.pem
./httpd-ssl/private/server-key.pem

The default behaviour is to look for the certificate and the private key in subdirectories certs/ and private/; those files will be used for the ssl settings in the httpd.

Default user

By default, Apache HTTP Server container runs as UID 1001. That means the volume mounted directories for the files (if mounted using -v option) need to be prepared properly, so the UID 1001 can read them.

To run the container as a different UID, use -u option. For example if you want to run the container as UID 1234, execute the following command:

docker run -d -u 1234 rhscl/httpd-24-rhel7

To log into a volume mounted directory, the container needs to be run as UID 0 (see above).

Troubleshooting

The httpd deamon in the container logs to the standard output by default, so the log is available in the container log. The log can be examined by running:

docker logs <container>

See also

Dockerfile and other sources for this container image are available on https://github.com/sclorg/httpd-container. In that repository, Dockerfile for CentOS is called Dockerfile, Dockerfile for RHEL is called Dockerfile.rhel7 and Dockerfile for Fedora is called Dockerfile.fedora.