Hi @weltonrodrigo and @dasniko , thanks so much for your help.
Yes, I have the cache-ispn-ha.xml in the conf directory. The application read oks this configuration.
I have remove the cache-stack=tcp of my code too.
Final code snippet in keycloak.conf is:
cache=ispn
cache-config-file=cache-ispn-ha.xml
The problem is in the discovery of the nodes.
I have this snippet in cache config file because I would like simply ping connection for discovery nodes.
<jgroups>
<stack name="tcpping" extends="tcp">
<TCP bind_port="7800" />
<TCPPING initial_hosts="redhattest1[7800],redhattest2[7800]" port_range="0" max_dynamic_hosts="2"/>
</stack>
</jgroups>
<cache-container name="keycloak">
<transport cluster="mykeycloak" lock-timeout="60000" stack="tcpping" node-name="redhattestttt1"/>
<local-cache name="realms">
Tested too with internal ip address.
It should work but not, when I launch 2 keycloak instances appear 2 nodes as a coordinator (not ok).
I think perhaps the problem is use Azure virtual machines.
I have firewalld enabled for this ports for 2 servers and enabled rule AllowVnetInBound enabled in networks for each virtual machine in Azure Portal.
[redhat@redhattest1 ~]$ sudo firewall-cmd --zone=public --permanent --list-ports
80/tcp 443/tcp 7800/tcp 7800/udp
I want to define this custom tcp solution (or similar) for discovery (no azure solution with AZURE_PING) because this is a POC in Azure but I want to install Keycloak quarkus in a Bare metal corporate infraestructure.
It would have to be possible but maybe I’ll try the solution with AZURE_PING and I already left the horns on the baremetal machine when I play and I assume that the ping problem was because it was azure 
I think the documentation of new Keycloak Quarkus (Guides - Keycloak) is simply and clair but insufficient on this documentation for use cases as common as tcpping on “normal” unix servers (not azure, ec, google).
Any idea?
Thanks for your help.
Xavier.