changes in design and multi-instance

common/docs/knowledgeBase/MultiInstance-Configuration.txt

+CONFIGURING MULTI-INSTANCE FOR MCX
 
+- First we need to enable private ips on all instances:
+  https://www.digitalocean.com/docs/networking/vpc/how-to/enable/
+  This way we don't pay for the traffic among those instances as long as they communicate via their
+  private ips.
+  The instances must be under the same VPC (Virtual ,private connection) to receive the same ip range and rules.
+
+- Altough we have private ips, the ports among them are not open, we still need to allow ports among them.
+  In order to get from one service to another on other instance on the same VPC, we need to add the port
+  to the firewall but in the 'Sources' section add the VPC name and delete other tags like 'All IPV4','All IPv6'.
+
+- Now we need to add the remote services (the services on the other instance) on each docker-compose files as 'extra_hosts'
+  using their private ip, e.g: 
+  extra_hosts:
+      - "alerts:10.136.0.2"
+      - "scp:10.136.0.2"
+  The port binding in the docker-compose is the same e.g: '- 8090:8080' just note that now the remote service must point to
+  the external exposed port, not the internal (like when both services are on the same instance).
    
-[Enable Private ip]
-https://www.digitalocean.com/docs/networking/vpc/how-to/enable/
 
-[docker port binding]
-In order to get from one service to another on other instance on the same VPC, we need to add the port
-to the firewall but in the 'Sources' section add the VPC name and delete other tags like 'All IPV4','All IPv6'.