Supporting multiple Edge UI instances

You can install multiple instances of the Edge UI in a high availability scenario. However, after installing the two instances of the Edge UI, you must perform post-installation tasks in order to synchronize the property settings between the two.

Specifically, you must configure the two UI instances to have the same value for the following properties:

application.secret=value
mail.smtp.credential=value
apigee.mgmt.credential=value

Additionally, if you configure them to use TLS, then you must ensure that you use the same cert and key on both instances.

Configure Edge UI instances using HTTP

Log in to the node hosting the first Edge UI instances (do not log in to the UI itself, but as a user on the node).
Open /opt/apigee/edge-ui/conf/apigee.conf in an editor and copy the values of the following properties for later use:
```
mail.smtp.credential="value"
apigee.mgmt.credential="value"
```
Open /opt/apigee/edge-ui/conf/application.conf in an editor and copy the values of the following property for later use:
```
application.secret="value"
```
Log in to the node hosting the second Edge UI instances.
Open /opt/apigee/customer/application/ui.properties on the second UI instance in an editor. If the file does not exist, create it.
Add the following properties to /opt/apigee/customer/application/ui.properties, including the values that you copied from the first UI instance:
```
conf_application_application.secret="value"
conf_apigee_mail.smtp.credential="value"
conf_apigee_apigee.mgmt.credential="value"
```
Notice how you prefix these values with either conf_application_ or conf_apigee_.
Save the file.
Make sure /opt/apigee/customer/application/ui.properties is owned by the "apigee" user:
```
chown apigee:apigee /opt/apigee/customer/application/ui.properties
```

Restart the second UI instance:

/opt/apigee/apigee-service/bin/apigee-service edge-ui restart

Users can now log in to either UI instance.

Configure Edge UI instances using TLS/HTTPS

Configure the first UI instance to use TLS/HTTPS as described in Configuring TLS for the management UI.
Configure the second Edge UI instances as described above for HTTP to synchronize the required properties.
Copy the JKS file containing the cert and key from the first UI instance to the node hosting the second UI instance.
Configure the second UI instance to use TLS/HTTPS as described in Configuring TLS for the management UI.