Docker openLDAP

A Docker image running OpenLDAP on Debian stable (jessie at the moment). The Dockerfile is inspired by cnry/openldap, but as said before, running a stable Debian and be a little less verbose, but more complete in the configuration.

NOTE: On purpose, there is no secured channel (TLS/SSL), because I believe that this service should never be exposed to the internet, but only be used directly by other Docker containers using the --link option.

Usage

The most simple form would be to start the application like so (however this is not the recommended way - see below):

docker run -d -p 389:389 -e SLAPD_PASSWORD=mysecretpassword -e SLAPD_DOMAIN=ldap.example.org dinkel/openldap

To get the full potential this image offers, one should first create a data-only container (see "Data persistence" below), start the OpenLDAP daemon as follows:

docker run -d -name openldap --volumes-from your-data-container dinkel/openldap

An application talking to OpenLDAP should then --link the container:

docker run -d --link openldap:openldap image-using-openldap

The name after the colon in the --link section is the hostname where the OpenLDAP daemon is listening to (the port is the default port 389).

Configuration (environment variables)

For the first run, one has to set at least two environment variables. The first

SLAPD_PASSWORD

sets the password for the admin user.

The second

SLAPD_DOMAIN

sets the DC (Domain component) parts. E.g. if one sets it to ldap.example.org, the generated base DC parts would be ...,dc=ldap,dc=example,dc=org.

There is an optinal third variable

SLAPD_ORGANIZATION (defaults to $SLAPD_DOMAIN)

that represents the human readable company name (e.g. Example Inc.).

The fourth (somewhat) optional variable

SLAPD_CONFIG_PASSWORD

allows password protected access to the dn=config branch. This helps to reconfigure the server without interruption (read the official documentation).

One can load additional schemas provided in the slapd package that are not installed using the

SLAPD_ADDITIONAL_SCHEMAS

environment variable with comma-separated enties. As of writing these instructions, there are the following additional schemas available: collective, corba, duaconf, dyngroup, java, misc, openldap, pmi and ppolicy.

At least one quite common module is neither loaded nor configured by default (I am talking about the memberof overlay). In order to activate this (and possibly other modules in the future), there is another environment variable called

SLAPD_ADDITIONAL_MODULES

which can hold comma-separated enties. It will try to run .ldif files with a corresponsing name from the module directory. Currently only memberof is avaliable.

After the first start of the image (and the initial configuration), these envirnonment variables are not evaluated anymore.

Data persistence

The image exposes two directories (VOLUME ["/etc/ldap", "/var/lib/ldap"]). The first holds the "static" configuration while the second holds the actual database. Please make sure that these two directories are saved (in a data-only container or alike) in order to make sure that everything is restored after a restart of the container.