Thursday, March 5, 2015

Labs: Using Couchbase's upcoming LDAP functionality with AD leveraging Centrify’s LDAP Proxy

Background
Couchbase is including LDAP support in the upcoming March release and we wanted to preview how to leverage your existing Centrify assets to help with this scenario.  The instructions below are for testing purposes only.
This capability will provide the ability to use LDAP users (From AD or other LDAP directories) to be provisioned as Full or Read-only administrators of the web console.

About this configuration
In this configuration  Couchbase is using saslauthd to connect to LDAP.  By leveraging the Centrify LDAP Proxy, this configuration can benefit from the robust capabilities of the Centrify agent (AD sites and services awareness, performance, caching, etc).



What’s required?


Instructions (All steps on CentOS 6.x)

Step 1 – Install the Centrify Agent and join AD
  1. With a privileged user, install the Centrify agent.
    rpm –Uvh centrifydc-<version>  (e.g. centrifydc-5.2.2-rhel3-x86_64.rpm)
  2.  Check if all is OK to join Active Directory
    adcheck <your domain>  (e.g. adcheck corp.contoso.com)
    Make sure you fix any issues (e.g. DNS, DC connectivity, etc)
  3. Join active directory (you’ll need an account that can join computers in AD)
    adjoin –z Model –c “ou=Servers,ou=UNIX” –u jerry.seinfeld -V corp.contoso.com
    Joins the corp.contoso.com in Centrify zone mode (Model) mode, and places the computer on the /UNIX/Servers OU and uses jerrry.seinfeld's  account for the corp.contoso.com domain.

Step 2 – Install, configure, start and test the Centrify LDAP Proxy
  1. Install the Centrify LDAP Proxyrpm – Uvh centrify-ldapproxy-<version>  (e.g. centrifydc-ldapproxy-5.2.2-rhel3-x86_64.rpm)
  2. Elevate and start the proxy manually or configure a startup script.  For example
    dzdo /usr/share/centrifydc/libexec/slapd  -f /etc/centrifydc/openldap/ldapproxy.slapd.conf -h ldap://cen1.corp.contoso.com
    This makes the LDAP proxy to start reading the indicated startup file and listens to the hostname cen1.corp.contoso.com
  3. To test that the LDAP proxy is responding to queries, use ldapsearch:$ /usr/share/centrifydc/bin/ldapsearch -h cen1.corp.contoso.com -x -b "ou=staff,dc=corp,dc=contoso,dc=com" "(cn=George Constanza)"
  4. Your search should yield results.

Step 3 – Install and Configure and Test saslauthd for LDAP
  1. Install cyrus-sasl (saslauthd)$ dzdo yum install cyrus-sasl
  2. Configure SASL for LDAP
  • a.       Edit the /etc/sysconfig/saslauthd and make sure the MECH parameter is set to LDAPMECH = ldap
  • b.      Configure the LDAP parameters for SASL the config file should be on /etc/saslauthd.conf. You need to add the ldap_server parameter (the system running the Centrify LDAP proxy) as well as your search base and the attribute that corresponds to the user name.  With Centrify you can use the AD name (samAccountName) or the uid contained in the PosixAccount class.  In my test scenario:
    ldap_servers: ldap://cen1.corp.contoso.comldap_search_base: ou=Staff,dc=corp,dc=contoso,dc=com=ldap_filter: (samAccountName=%u)

    Note that in a production environment you’ll use multiple proxies for HA and secure LDAP (ldaps://) and most likely your Couchbase configuration will be clustered.  Use the same availability controls for the Authentication that you are using for the cluster.
  • c.       Start the saslauthd service (or set it to start automatically with chkconfig)$ dzdo service saslauthd start
  1. Test saslauthd for LDAPUse the testsaslauth script to test LDAP authentication:/usr/sbin/testsaslauthd -u george.constanza -p <cleartextpw> -f /var/run/saslauthd/mux
  2. If everything is well set up, the output should be:  0: OK "Success."
Steps 1 to 3 - Potential misconfigurations:
  • Firewall ports are not open for LDAP
  • The Proxy is not started or hasn't started with the appropriate protocol or hostname.
  • The configuration of saslauthd is incorrect (look at /etc/sysconfig/saslauthd OR /etc/saslauthd.conf)
  • Your LDAP filters are not correct.

Step 4 – Install Couchbase and Perform Initial Setup
  1. Obtain the new bits that support LDAP: wget http://latestbuilds.hq.couchbase.com/couchbase-server/sherlock/1415/couchbase-server-enterprise-3.5.0-1415-centos6.x86_64.rpm
  2. Add the following lines to the /etc/rc.localfor i in /sys/kernel/mm/*transparent_hugepage/enabled; doecho never > $i; donefor i in /sys/kernel/mm/*transparent_hugepage/defrag; doecho never > $i; done 
  3. Save and reboot the server.
  4. Install couchbase$ dzdo rpm --install couchbase-server-version.rpm
  5. Provided that your firewall ports are open, you can go to a browser and navigate to the Couchbase admin page:  http://your-hostname:8091
  6. Follow the steps to complete the initial configuration (hostname, cluster, sample apps, Administrative user, etc)
Note: In my environment I performed a reboot.  Keep in mind that if you ran the Centrify LDAP proxy manually, you need to launch it again and restart saslauthd before the next step.

Step 4 – Set up Couchbase for LDAP and test settings
  1.  Log in to the couchbase administrative interface with your administrator account.
  2. Navigate to Settings > LDAP Auth Setup
  3. Under Setup, check the Enable Checkbox and press Save.
  4. Add a Full or Read-Only administrator
    (I used the AD username, since my LDAP filter uses samAccountName).  E.g. George.Constanza
  5. To test the user, use the Validate box.
  6. Sign out of the Console.  Attempt login with the newly assigned Admin.   If your admin is Full, they’ll get access to all the settings, if they are read-only, they’ll get the settings grayed out.

Summary

Setup was fairly simple using the Centrify LDAP proxy.  The benefits are tangible because the underlying adclient agent serves as a way not to have to maintain multiple LDAP entries and for additional performance gains.  Keep in mind, this was a "quick-and-dirty" setup, in reality you would have to account for LDAPS and HA.

As far as Couchbase goes, I was very impressed with how simple it was to set up and things just worked. They have been adding security features incrementally, and we are hoping that we can see them leverage PAM, Kerberos, PKI and to be able to leverage NSS UNIX users/groups for at least administrative interfaces; this will enable Centrify users to expose AD capabilities and accelerate the security posture of the platform.  We are keeping our eyes and ears locked on these newer technologies.

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