I upgraded to 6.0.0-rc2 on Monday. This morning, when I tried to upgrade to 6.0 GA with "rpm -Uvh" it tells me the rc2 packages are newer than the GA packages (except for logstash). I guess I need to "rpm -e ; rpm -i" instead ...
Unfortunately "rpm -e ; rpm -i" removes the local user ids and then recreates them with different values. The new kibana user has the same uid as the old elasticsearch user
warning: [...]auditbeat-6.0.0-x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
package auditbeat-6.0.0_rc2-1.x86_64 (which is newer than auditbeat-6.0.0-1.x86_64) is already installed
warning: [...]elasticsearch-6.0.0.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
package elasticsearch-0:6.0.0_rc2-1.noarch (which is newer than elasticsearch-0:6.0.0-1.noarch) is already installed
warning: [...]filebeat-6.0.0-x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
package filebeat-6.0.0_rc2-1.x86_64 (which is newer than filebeat-6.0.0-1.x86_64) is already installed
warning: [...]kibana-6.0.0-x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
package kibana-6.0.0_rc2-1.x86_64 (which is newer than kibana-6.0.0-1.x86_64) is already installed
warning: [...]logstash-6.0.0.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
1:logstash ########################################### [100%]
Using provided startup.options file: /etc/logstash/startup.options
Successfully created system startup script for Logstash
warning: [...]metricbeat-6.0.0-x86_64.rpm: Header V4 RSA/SHA512 Signature, key ID d88e42b4: NOKEY
Preparing... ########################################### [100%]
package metricbeat-6.0.0_rc2-1.x86_64 (which is newer than metricbeat-6.0.0-1.x86_64) is already installed