[enhancement] Modify the key word

[andyli029]

Summary

master->leader
slave->follower

tt-krypton-master           NodePort    10.96.42.194    <none>        3306:32370/TCP      102m
tt-krypton-metrics          ClusterIP   None            <none>        9104/TCP            102m
tt-krypton-slave            NodePort    10.96.21.243    <none>        3306:30545/TCP      102m

[runkecheng]

The chart name should be xenondb.

https://github.com/andyli029/krypton-helm/blob/master/charts/Chart.yaml#L2

To connect to master service in the Ubuntu pod:

    mysql -h {{ template "fullname" . }}-master -u {{ .Values.mysql.mysqlUser }} -p

{{- if lt 1 (.Values.replicaCount | int64) }}

To connect to slave service (read-only) in the Ubuntu pod:

    mysql -h {{ template "fullname" . }}-slave -u {{ .Values.mysql.mysqlUser }} -p

The definition of fullname in templates/_helpers.tpl.

{{/*
Create a default fully qualified app name.
The format of host is "fullname"-0."fullname"."namespace" (podname.servicename.namespace), 
and the MySQL limits the total length of master_host to 60 byte, 
so the length of "fullname" must be limited to '(60-4-len(namespace))/2'.
*/}}
{{- define "fullname" -}}
{{- $length := div (sub 56 (len .Release.Namespace )) 2 | int }}
{{- if .Values.fullnameOverride -}}
{{- .Values.fullnameOverride | trunc $length | trimSuffix "-" -}}
{{- else -}}
{{- $name := default .Chart.Name .Values.nameOverride -}}
{{- if contains $name .Release.Name -}}
{{- .Release.Name | trunc $length | trimSuffix "-" -}}
{{- else -}}
{{- printf "%s-%s" .Release.Name $name | trunc $length | trimSuffix "-" -}}
{{- end -}}
{{- end -}}
{{- end -}}