I sucess update elastic (2 node) from 5.1 to 6.0，and install x-pack to elastic6.0 ，elastic6.0 cluster work ok.
then,update kibana to 6,and install x-pack to kibana sucessful .but kibana console can not login with"Login is currently disabled. Administrators should consult the Kibana logs for more details."
detail kibana log show :
log [01:39:39.111] [info][status][plugin:kibana@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:39.216] [info][status][plugin:elasticsearch@6.0.0] Status changed from uninitialized to yellow - Waiting for Elasticsearch
log [01:39:39.227] [info][status][plugin:xpack_main@6.0.0] Status changed from uninitialized to yellow - Waiting for Elasticsearch
log [01:39:39.734] [info][status][plugin:graph@6.0.0] Status changed from uninitialized to yellow - Waiting for Elasticsearch
log [01:39:39.769] [info][status][plugin:monitoring@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:42.770] [warning][reporting] Generating a random key for xpack.reporting.encryptionKey. To prevent pending reports from failing on restart, please set xpack.reporting.encryptionKey in kibana.yml
log [01:39:42.780] [info][status][plugin:reporting@6.0.0] Status changed from uninitialized to yellow - Waiting for Elasticsearch
log [01:39:42.833] [error][status][plugin:xpack_main@6.0.0] Status changed from yellow to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.834] [error][status][plugin:graph@6.0.0] Status changed from yellow to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.836] [error][status][plugin:reporting@6.0.0] Status changed from yellow to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.837] [error][status][plugin:elasticsearch@6.0.0] Status changed from yellow to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.848] [error][status][plugin:security@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.849] [warning][security] Generating a random key for xpack.security.encryptionKey. To prevent sessions from being invalidated on restart, please set xpack.security.encryptionKey in kibana.yml
log [01:39:42.861] [warning][security] Session cookies will be transmitted over insecure connections. This is not recommended.
log [01:39:42.916] [error][status][plugin:searchprofiler@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.929] [error][status][plugin:ml@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:42.995] [info][status][plugin:ml@6.0.0] Status changed from red to yellow - Waiting for Elasticsearch
log [01:39:43.018] [error][status][plugin:tilemap@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:43.025] [info][status][plugin:ml@6.0.0] Status changed from yellow to green - Ready
log [01:39:43.031] [error][status][plugin:watcher@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:43.070] [info][status][plugin:grokdebugger@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:43.084] [info][status][plugin:dashboard_mode@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:43.090] [error][status][plugin:logstash@6.0.0] Status changed from uninitialized to red - Your Kibana index is out of date, reset it or use the X-Pack upgrade assistant.
log [01:39:43.124] [info][status][plugin:console@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:43.143] [info][status][plugin:metrics@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:43.404] [info][status][plugin:timelion@6.0.0] Status changed from uninitialized to green - Ready
log [01:39:43.411] [info][listening] Server running at http://10.23.16.196:80
log [01:39:43.413] [error][status][ui settings] Status changed from uninitialized to red - Elasticsearch plugin is red
my kibana.yml was alredy add elastic's credential .
how reset Kibana index or use the X-Pack upgrade assistant ?
thanks ！