question Re: KDC Server Connection is not available. Unable to login in Support Questions

KDC Server Connection is not available. Unable to login

BrianChan — Tue, 21 Apr 2026 07:15:26 GMT

Hi all,

I have a cluster in CDP version 7.1.8 private cloud base. The Cloudera Management service show bad health and indicate that the connection to KDC server is not available.

I can regenerate missing credentials under Administration > Security > Kerberos Credentials

Moreover, I can do kinit in the CM server host. Therefore I have no idea why the connection shows failure.

Please let me know if I should provide further information. Thank you.

Re: KDC Server Connection is not available. Unable to login

BrianChan — Wed, 03 May 2023 07:06:23 GMT

From the system log, I found error saying unsupported Keytype. I am using OpenJDK 8u332.

Do anyone know how to solve this? Thank you.

Re: KDC Server Connection is not available. Unable to login

BrianChan — Tue, 09 May 2023 10:20:10 GMT

I finally managed to solve the problem by switching the OpenJDK version from 8u362 to 8u232.

However, is OpenJDK 8u232 the only version that support when working on CDP 7.1.8 with Kerberos enabled?

Could someone clarify it for me please? Thank you.

Re: KDC Server Connection is not available. Unable to login

hardik2909 — Fri, 26 Jan 2024 01:17:06 GMT

I am seeing the same issue and cant seem to find a way around it on Private Cloud Base 7.1.9 with AD based kerberos.
JAVA SE jdk11 and krb5.conf is set according to https://docs.cloudera.com/cdp-private-cloud-base/7.1.8/security-kerberos-authentication/topics/cm-security-kerberos-authentication-overview.html

CMSERVER:<fqdn>: KDC Server Connection is not available. Unable to login.

Appreciate any help I can get to resolve this error.

Thank you!

Re: KDC Server Connection is not available. Unable to login

venkatsambath — Fri, 26 Jan 2024 17:12:59 GMT

Can you share the exact error you notice in CM server log around the timeframe in which you notice the error 'CMSERVER:<fqdn>: KDC Server Connection is not available. Unable to login.', the full exception from cm server log will help to understand the issue better.

Re: KDC Server Connection is not available. Unable to login

DianaTorres — Tue, 30 Jan 2024 20:04:23 GMT

@hardik2909 If you are still experiencing the issue, can you provide the information @venkatsambath has requested? Thanks.

Re: KDC Server Connection is not available. Unable to login

hardik2909 — Thu, 01 Feb 2024 20:59:09 GMT

@venkatsambath
I was able to resolve the error by adding all supported kerberos Encryption Types instead of only default 'rc4-hmac'.
FYI added : rc4-hmac aes256-cts aes128-cts des-cbc-crc des-cbc-md5

Re: KDC Server Connection is not available. Unable to login

Aqdas — Wed, 15 May 2024 06:09:20 GMT

Hi @DianaTorres ,

I am facing the same issue. Can you please connect me with someone who can help me resolve this issue?

Thanks

Re: KDC Server Connection is not available. Unable to login

DianaTorres — Wed, 15 May 2024 19:52:48 GMT

@Aqdas Welcome to the Cloudera Community!

To help you get the best possible solution, I have tagged our Kerberos experts @venkatsambath @james_jones @pajoshi who may be able to assist you further.