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   image:https://github.com/killbill/killbill-docs/raw/v3/userguide/assets/aws/ELB-check-listeners.png[align=center]
   
  -== Create a Certificate
  +== Enabling HTTPS
   
   We recommend for security that you choose the HTTPS protocol to access KAUI. This protocol uses SSL/TLS encryption and authentication to verify and protect all communication with the KAUI server. To use this protocol you must create or provide an X.509 certificate. This section describes how to create a certificate using the *Amazon Certificate Manager (ACM).*
   
  -==== 1. Request a Certificate
  +=== 1. Request a Certificate
   
   When you click on *Request a new Certificate from ACM*, as described above, you will be taken to the main page of the ACM. Initially this will probably show that you have no certificates. Click *Request a Certificate*.
   
  
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  If you make changes to these configuration files, remember to make the same changes to *all* your EC2 instances!
  
  == Upgrades
  
  From time to time new versions of Kill Bill and KAUI may be released. This section explains how to upgrade to these new versions. You will need to follow these procedures for *each* of your instances.
  
  
negative.code: = Multitier Option
  
  
  There are three different ways to setup a working Kill Bill system on AWS, using software preconfigured by Kill Bill. Two options are based on a single *Amazon Machine Image (AMI)* containing the complete Kill Bill stack, that is both the Kill Bill server and the administrative UI (KAUI). These options are *single tier* and *multitier*. The https://docs.killbill.io/latest//aws-singletier.html[*single tier* option] is designed to deploy a limited version of Kill Bill quickly for trial and experimentation. For production deployments, we offer the multitier option. A third alternative available for deploying a production system is https://docs.killbill.io/latest//aws-cf.html[CloudFormation templates]. The multitier option requires more setup than CloudFormation, but provides more control over the deployment.
  
  == Overview
  
  