kubernetes with custom CA bundle - certificate verify failed

Summary

gitlab ce 8.17.2

certificate verify failed with custom CA bundle

Steps to reproduce

according this page https://docs.gitlab.com/ce/user/project/integrations/kubernetes.html i try to connect to my kubernetes API server with custom CA bundle

What is the current bug behavior?

certificate verify failed

What is the expected correct behavior?

openssl s_client -connect 10.123.8.14:443 -CAfile bundle.pem

Verify return code: 0 (ok)

Relevant logs and/or screenshots

FROM kubernetes API Server (v1.5.3) i got following error

0320 09:54:28.087135       1 logs.go:41] http: TLS handshake error from 10.111.0.141:50889: remote error: tls: unknown certificate authority