docker exec -it elasticsearch /bin/bash

[root@njfdkb4bmk3b elasticsearch]# ./bin/elasticsearch-setup-passwords -h
Sets the passwords for reserved users

Commands
--------
auto - Uses randomly generated passwords
interactive - Uses passwords entered by a user

Non-option arguments:
command              

Option             Description        
------             -----------        
-E <KeyValuePair>  Configure a setting
-h, --help         Show help          
-s, --silent       Show minimal output
-v, --verbose      Show verbose output

[root@cfeeab4bb0eb elasticsearch]# ./bin/elasticsearch-setup-passwords auto
Initiating the setup of passwords for reserved users elastic,apm_system,kibana,logstash_system,beats_system,remote_monitoring_user.
The passwords will be randomly generated and printed to the console.
Please confirm that you would like to continue [y/N]y


Changed password for user apm_system
PASSWORD apm_system = YxVzeT9B2jEDUjYp66Ws

Changed password for user kibana
PASSWORD kibana = 8NnThbj0N02iDaTGhidU

Changed password for user logstash_system
PASSWORD logstash_system = 9nIDGe7KSV8SQidSk8Dj

Changed password for user beats_system
PASSWORD beats_system = qeuVaf1VEALpJHfEUOjJ

Changed password for user remote_monitoring_user
PASSWORD remote_monitoring_user = DtZCrCkVTZsinRn3tW3D

Changed password for user elastic
PASSWORD elastic = q5f2qNfUJQyvZPIz57MZ

docker exec -it elasticsearch /bin/bash

./bin/elasticsearch-users useradd ryan -r superuser
Enter new password:
ERROR: Invalid password...passwords must be at least [6] characters long
[root@cfeeab4bb0eb elasticsearch]# ./bin/elasticsearch-users useradd ryan -r superuser
Enter new password:
Retype new password:

curl -XPUT -u ryan:ryan123 http://localhost:9200/_xpack/security/user/elastic/_password -H
"Content-Type: application/json" -d '
{
  "password": "q5f2qNfUJQyvZPIz57MZ"
}'