[jira] [Created] (AMBARI-15324) Kerberos Tickets Expire Too Frequently For Alerts

["Jonathan Hurley (JIRA)" <ji...@apache.org>]

Jonathan Hurley created AMBARI-15324:
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             Summary: Kerberos Tickets Expire Too Frequently For Alerts
                 Key: AMBARI-15324
                 URL: https://issues.apache.org/jira/browse/AMBARI-15324
             Project: Ambari
          Issue Type: Bug
          Components: ambari-agent
    Affects Versions: 2.1.0
            Reporter: Jonathan Hurley
            Assignee: Jonathan Hurley
            Priority: Critical
             Fix For: 2.2.2


When a cluster has been Kerberized, alerts use the {{curl_krb_request}} module in order to make requests using SPNEGO negotiation.

Normally this would involve calling {{kinit}} and then invoking the {{curl}} command to use the acquired ticket. However, because alerts run often on fixed intervals, this would mean that the KDC would be flooded with requests every minute.

To alleviate this problem, {{curl_krb_request}} uses {{klist}} to inspect the {{KRB5CCNAME}} cache. Only if an invalid ticket is found is {{kinit}} invoked. Additionally, {{kinit}} is invoked with a fixed ticket lifetime of 5 minutes. Since many alerts run on 5-minute intervals, this causes boundary issues.

To workaround these problems while continuing to leverage the cache, {{curl_krb_request}} should be changed to:
- Use the default ticket expiry configured for Kerberos in {{krb5.conf}}
- Employ in-memory tracking of the last time {{kinit}} was called so that it can be invoked before hitting the boundary of the ticket's expiration time



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