Cloudera Docs

Set Proxy Server Authentication for Clusters Using Kerberos

In a cluster using Kerberos, applications check host credentials to verify that the host they are connecting to is the same one that is actually processing the request, to prevent man-in-the-middle attacks. To clarify that the load-balancing proxy server is legitimate, you need to perform these extra Kerberos setup steps.

This procedure assumes you are starting with a Kerberos-enabled cluster.

  1. Choose the host you will use for the proxy server. Based on the Kerberos setup procedure, it should already have an entry solr/proxy_host@realm in its keytab.
  2. Navigate to Solr service > Configuration > Category > Main.
  3. Set the value of Solr Load Balancer to <hostname>:<port>, specifying the hostname and port of the proxy host.
  4. Click Save Changes.
  5. Launch the Stale Configuration wizard to restart the Solr service and any dependent services.

    Cloudera Manager transparently handles the keytab and dependent service updates by setting SOLR_AUTHENTICATION_KERBEROS_PRINCIPAL=* under /etc/default/solr and by generating a merged keytab that includes the HTTP principal of the load balancer in addition to the own HTTP principal of the Solr server.

  6. You can verify that the merged keytabs have been created and they contain the HTTP principal for both the load balancer and the particular Solr server by checking the process directory of Solr in /var/run/cloudera-scm-agent/process:
    For example:
    # klist -kte 291-solr-SOLR_SERVER/solr.keytab
Keytab name: FILE:291-solr-SOLR_SERVER/solr.keytab
KVNO Timestamp         Principal
---- ----------------- --------------------------------------------------------
   2 01/21/20 06:08:05 HTTP/loadbalancer.example.com@EXAMPLE.COM (des3-cbc-sha1)
   2 01/21/20 06:08:05 HTTP/loadbalancer.example.com@EXAMPLE.COM (arcfour-hmac)
   2 01/21/20 06:08:05 HTTP/loadbalancer.example.com@EXAMPLE.COM (des-hmac-sha1)
   2 01/21/20 06:08:05 HTTP/loadbalancer.example.com@EXAMPLE.COM (des-cbc-md5)
   2 01/21/20 06:08:05 HTTP/solrserver1.example.com@EXAMPLE.COM (des3-cbc-sha1)
   2 01/21/20 06:08:05 HTTP/solrserver1.example.com@EXAMPLE.COM (arcfour-hmac)
   2 01/21/20 06:08:05 HTTP/solrserver1.example.com@EXAMPLE.COM (des-hmac-sha1)
   2 01/21/20 06:08:05 HTTP/solrserver1.example.com@EXAMPLE.COM (des-cbc-md5)
   2 01/21/20 06:08:05 solr/solrserver1.example.com@EXAMPLE.COM (des3-cbc-sha1)
   2 01/21/20 06:08:05 solr/solrserver1.example.com@EXAMPLE.COM (arcfour-hmac)
   2 01/21/20 06:08:05 solr/solrserver1.example.com@EXAMPLE.COM (des-hmac-sha1)
   2 01/21/20 06:08:05 solr/solrserver1.example.com@EXAMPLE.COM (des-cbc-md5)