Hey! Recently along with Sanderv32 we have been trying to get LDAP authentication working on Redhat machines. I must admit that we have spent some quite looking for more structured and decent information how to get this working. However up to our surprise information were completely inaccurate or outdated.

So without big delays we have decided to tackle this challenge using Ansible. Of course first attempts were just to get the idea working. As we were moving our playbook were growing to reach stage at which we could deploy LDAP authentication mechanism to all of our RedHat 7 systems

Below is the output of the runbook being used:

    - name: "LDAP Authentication | Install the required packages"
      yum: >
        name="{{item}}"
        state=present
      with_items:
        - "nss-pam-ldapd"
        - "oddjob"
        - "oddjob-mkhomedir"
      tags:
        - "ldap"
        - "packages"
        - "packages_ldap"

    - name: "LDAP Authentication | Ensure services are running"
      service:
          name={{item}}
          enabled=yes
          state=started
      with_items:
        - "nscd"
        - "nslcd"
        - "oddjobd"
      register: services_ldap
      tags:
        - "ldap"
        - "services_ldap"

    - name: "Debug | Display results"
      debug: msg="{{services_ldap.results}}"
      tags:
        - "ldap"

    - name: "LDAP Authentication | Enable LDAP PAM modules"
      command: "authconfig --enableldap --enableldapauth --enablemkhomedir --update"
      tags:
        - "ldap"

    - name: "LDAP Authentication | Adding configuration templates"
      template: >
        src="templates/{{item}}.j2"
        dest="/etc/{{item}}"
      with_items:
        - "nslcd.conf"
      tags:
        - "ldap"
        - "repository"
        - "repository_ldap"
      notify:
        - restart services ldap

And associated handler

---
  - name: "restart services ldap"
    service: >
      name="{{item.name}}" 
      state=restarted
    with_items: services_ldap.results
    tags:
      - "ldap"
      - "services_ldap"

In the above I have highlighted the part which we use to template NLSCD config file. The file contents are completely overwritten so make sure you adjust it to your needs.

This template has been used to connect to Active Directory with dedicated bind user and modified pagesize ( so our results are not trimmed )

# {{ ansible_managed }}
uid nslcd
gid ldap

uri {{ ldap.uri }}
base {{ ldap.basedn }}
binddn {{ ldap.binduser }}
bindpw {{ ldap.binduserpw }}
scope sub
tls_reqcert allow

pagesize 10000
referrals off
idle_timelimit 800
filter passwd (&(objectClass=user)(!(objectClass=computer))(uidNumber=*)(unixHomeDirectory=*))
map    passwd uid              sAMAccountName
map    passwd homeDirectory    unixHomeDirectory
map    passwd gecos            displayName
map    passwd loginShell       "/bin/bash"
filter shadow (&(objectClass=user)(!(objectClass=computer))(uidNumber=*)(unixHomeDirectory=*))
map    shadow uid              sAMAccountName
map    shadow shadowLastChange pwdLastSet
filter group  (objectClass=group)


ssl no
tls_cacertdir /etc/openldap/cacerts

Thats it folks! If it would not work with you please leave some comments as this is used to make sure we have means of using LDAP auth on Linux boxes

Intro

If you are working with environments where certain policies and rules needs to be applied something like CIS baselines will be well known to you.

So it works on basis where you define which points you will apply to your system and from that point onwards you are expected to deliver proof that this is how ur systems are now compliant (or not ) and if you do not apply certain settings what is the reason for it .

However the problem comes when you need to enforce this compliancy on multiple systems and make sure they are all happily running this policies.

Automation:

And here comes the really good part – where you take a configuration management tool like Ansible and create a reusable piece of code which defines your infrastructure. Although looking at CIS baseline documents – if you are to start from zero that would be a lot of work … but …. good friend of mine has spent his time preparing CIS baseline for Redhat 7 which is no available on github in his repository HERE 🙂

And for much more interesting info you can always look at his blog under https://blog.verhaar.io

redhat

Redhat 7 – LDAP authentication using Ansible

Ansible role for Redhat 7 CIS baseline

Intro

Automation: