As noted in Installing Confluence Data Center, the parameter synchrony.service.url is used in both Confluence and Synchrony with different values:

• For Synchrony:

  -Dsynchrony.service.url=<YOUR_LOAD_BALANCER> 
  

  Value

  Description

  <YOUR_LOAD_BALANCER>

  This is the full URL of the load balancer Synchrony will run behind, for example, http://<lb_host>:<lb_port><lb_context_path>. For example, if your loadbalancer path is synchrony, then it will be http://hostname:80/synchrony. Notice that it does not end with /v1, unlike the synchrony.service.url system property passed to Confluence. If this URL doesn't match the URL coming from a users' browser, Synchrony will fail.

• For Confluence:

  1. Start Confluence on node 1 and pass the following system property to tell Confluence where to find your Synchrony cluster.
  -Dsynchrony.service.url=http://<YOUR_LOAD_BALANCER>:<LOAD_BALANCER_PORT>/synchrony/v1
  You may want to add this system property to your <install-directory>/bin/setenv.bin or setenv.bat so it is automatically passed every time you start Confluence.

Synchrony's synchrony.service.url should be check against Confluence's for any mismatch before displaying it status as "Running" because if a mismatch exists, Collaborative Editing doesn't work even if Synchrony is running.