Docker Image including CentOS-6, Apache 2.2, PHP 5.6, PHP memcached 1.0, PHP APCu, Composer.

The Dockerfile can be used to build a base image that can be run as-is or used as the bases for other more specific builds.

Included in the build is the EPEL repository and SSH, vi, elinks (for fullstatus support), APC, Memcache and Composer are installed along with python-pip, supervisor and supervisor-stdout.

Supervisor is used to start httpd (and optionally the sshd) daemon when a docker container based on this image is run. To enable simple viewing of stdout for the sshd subprocess, supervisor-stdout is included. This allows you to see output from the supervisord controlled subprocesses with docker logs <docker-container-name>.

SSH is not required in order to access a terminal for the running container the prefered method is to use Command Keys and the nsenter command. See command-keys.md for details on how to set this up.

If enabling and configuring SSH access, it is by public key authentication and, by default, the Vagrant insecure private key is required.

Run up a container named apache-php.app-1.1.1 from the docker image jdeathe/centos-ssh-apache-php on port 8080 of your docker host.

$ docker run -d \
  --name apache-php.app-1.1.1 \
  -p 8080:80 \
  --env SERVICE_UNIT_APP_GROUP=app-1 \
  --env SERVICE_UNIT_LOCAL_ID=1 \
  --env SERVICE_UNIT_INSTANCE=1 \
  --env APACHE_SERVER_NAME=app-1.local \
  --env APACHE_SERVER_ALIAS=app-1 \
  --env DATE_TIMEZONE=UTC \
  -v /var/services-data/apache-php/app-1:/var/www/app \
  jdeathe/centos-ssh-apache-php:latest

Now point your browser to http://<docker-host>:8080 where "<docker-host>" is the host name of your docker server and, if all went well, you should see the "Hello, world!" page.

Create a "data volume" for configuration, this allows you to share the same configuration between multiple docker containers and, by mounting a host directory into the data volume you can override the default configuration files provided.

Make a directory on the docker host for storing container configuration files. This directory needs to contain everything from the directory etc/services-config

$ mkdir -p /etc/services-config/apache-php.app-1.1.1

Create the data volume, mounting our docker host's configuration directory to /etc/services-config/ssh in the docker container. Docker will pull the busybox:latest image if you don't already have it available locally.

$ docker run \
  --name volume-config.apache-php.app-1.1.1 \
  -v /etc/services-config/ssh.pool-1:/etc/services-config/ssh \
  -v /etc/services-config/apache-php.app-1.1.1/supervisor:/etc/services-config/supervisor \
  -v /etc/services-config/apache-php.app-1.1.1/httpd:/etc/services-config/httpd \
  -v /etc/services-config/apache-php.app-1.1.1/ssl/certs:/etc/services-config/ssl/certs \
  -v /etc/services-config/apache-php.app-1.1.1/ssl/private:/etc/services-config/ssl/private \
  busybox:latest \
  /bin/true

To run the a docker container from this image you can use the included run.sh and run.conf scripts. The helper script will stop any running container of the same name, remove it and run a new daemonised container on an unspecified host port. Alternatively you can use the following.

$ docker stop apache-php.app-1.1.1 && \
  docker rm apache-php.app-1.1.1
$ docker run -d \
  --name apache-php.app-1.1.1 \
  -p 8080:80 \
  -p 8580:8443 \
  --env SERVICE_UNIT_INSTANCE=app-1 \
  --env SERVICE_UNIT_LOCAL_ID=1 \
  --env SERVICE_UNIT_INSTANCE=1 \
  --env APACHE_SERVER_NAME=app-1.local \
  --env APACHE_SERVER_ALIAS=app-1 \
  --env DATE_TIMEZONE=UTC \
  --volumes-from volume-config.apache-php.app-1.1.1 \
  -v /var/services-data/apache-php/app-1:/var/www/app \
  jdeathe/centos-ssh-apache-php:latest

Now you can verify it is initialised and running successfully by inspecting the container's logs

$ docker logs apache-php.app-1.1.1

The output of the logs should show the Apache modules being loaded and auto-generated password for the Apache user and group, (if not try again after a few seconds).

There are several environmental variables defined at runtime these allow the operator to customise the running container which may become necessary when running several on the same docker host, when clustering docker hosts or to simply set the timezone.

The SERVICE_UNIT environmental variables are used to set a response header named X-Service-Uid that lets you identify the container that is serving the content. This is useful when you have many containers running on a single host using differnt ports (i.e with differnet SERVICE_UNIT_LOCAL_ID values) or if you are running a cluster and need to identify which host the content is served from (i.e with different SERVICE_UNIT_INSTANCE values). The three values should map to the last 3 dotted values of the container name; in our case that is "app-1.1.1"

...
  --env SERVICE_UNIT_APP_GROUP=app-1 \
  --env SERVICE_UNIT_LOCAL_ID=1 \
  --env SERVICE_UNIT_INSTANCE=1 \
...

The APACHE_SERVER_NAME and APACHE_SERVER_ALIAS environmental variables are used to set the VirtualHost ServerName and ServerAlias values respectively. In the following example the running container would respond to the host names app-1.local or app-1:

...
  --env APACHE_SERVER_NAME=app-1.local \
  --env APACHE_SERVER_ALIAS=app-1 \
...

from your browser you can then access it with http://app-1.local:8080 assuming you have the IP address of your docker mapped to the hostname using your DNS server or a local hosts entry.

The default timezone for the container, and the PHP app, is UTC however the operator can set an appropriate timezone using the DATE_TIMEZONE variable. The value should be a timezone identifier, like UTC or Europe/London. The list of valid identifiers is available in the PHP List of Supported Timezones.

To set the timezone for the UK and account for British Summer Time you would use:

...
  --env DATE_TIMEZONE=Europe/London \
...

If using the optional data volume for container configuration you are able to customise the configuration. In the following examples your custom docker configuration files should be located on the Docker host under the directory /etc/service-config/<container-name>/ where <container-name> should match the applicable container name such as "apache-php.app-1.1.1" in the examples.

The bootstrap script initialises the app. It sets up the Apache service user + group, generates passwords, enables Apache modules and adds/removes SSL support.

Use the SERVICE_USER* variables in your custom apache-bootstrap.conf file to override this and to also define a custom username and/or group.

SERVICE_USER=apacheUser
SERVICE_USER_GROUP=apacheGroup
SERVICE_USER_PASSWORD=userPassword123
SERVICE_USER_GROUP_PASSWORD=userGroupPassword123

The variable APACHE_LOAD_MODULES defines all Apache modules to be loaded from /etc/httpd/conf/http.conf. The default is the minimum required so you may need to add more as necessary. To add the "mod_rewrite" Apache Module you would add it's identifier rewrite_module to the array as follows.

APACHE_LOAD_MODULES="
    authz_user_module
    log_config_module
    expires_module
    deflate_module
    headers_module
    setenvif_module
    mime_module
    status_module
    dir_module
    alias_module
    rewrite_module
"

By default SSL support is disabled but a second port, (mapped to 8443), is available for traffic that has been been through upstream SSL termination (SSL Offloading). If you want the container to support SSL directly then set APACHE_MOD_SSL_ENABLED=true this will then generate a self signed certificate and will update Apache to accept traffic on port 443.

Note: The included helper script run.sh will automatically map the docker host port 8580 to 443 but if you are running docker manually can use the following.

$ docker stop apache-php.app-1.1.1 && \
  docker rm apache-php.app-1.1.1
$ docker run -d \
  --name apache-php.app-1.1.1 \
  -p 8080:80 \
  -p 8580:443 \
  --env SERVICE_UNIT_APP_GROUP=app-1 \
  --env SERVICE_UNIT_LOCAL_ID=1 \
  --env SERVICE_UNIT_INSTANCE=1 \
  --env APACHE_SERVER_NAME=app-1.local \
  --env APACHE_SERVER_ALIAS=app-1 \
  --env DATE_TIMEZONE=UTC \
  --volumes-from volume-config.apache-php.app-1.1.1 \
  -v /var/services-data/apache-php/app-1:/var/www/app \
  jdeathe/centos-ssh-apache-php:latest

You may need to override the default auto-generated self signed certificate. To do this you can add the SSLCertificateFile to the Docker hosts directory using the filename localhost.crt for example:

/etc/services-config/apache-php.app-1.1.1/ssl/certs/localhost.crt

Note: You must also specify the associated SSLCertificateKeyFile in this case.

To override the SSLCertificateKeyFile add it to your config directory using the filename localhost.key for example:

/etc/services-config/apache-php.app-1.1.1/ssl/certs/localhost.key

Note: You must also specify the associated SSLCertificateFile in this case.

The supervisor service's configuration can also be overriden by editing the custom supervisord.conf file. It shouldn't be necessary to change the existing configuration here but you could include more [program:x] sections to run additional commands at startup.

In the previous example Docker run commands we mapped the Docker host directory /var/services-data/apache-php/app-1 to /var/www/app in the Docker container, where /var/services-data/ is the directory used to store persistent files and the subdirectory is used by an individual app's named container(s), apache-php.app-1.1.1, in the previous examples.

On first run, the bootstrap script, (/etc/apache-bootstrap), will check if the DocumentRoot directory is empty and, if so, will poplate it with the example app scripts and VirtualHost configuration files. If you place your own app in this directory it will not be overwritten but you must ensure to include at least a vhost.conf file and, if enabling SSL a vhost-ssl.conf file too.