Synchrony cluster failed to start with outbound proxy in AWS

If your synchrony cluster failed to start in AWS, the Collaborative Edit in Confluence will not work. And if your environment meet all the following criteria. Then I think you are in the right place. As I had the same issue, and finally figured it out that Synchrony has seperate JVM settings. The proxy settings for Confluence JVM does not pass to Synchrony. Check this out: https://bitbucket.org/atlassian/atlassian-aws-deployment/issues/44/synchrony-cluster-failed-to-start-with. Technically, it is a Confluence bug.

• Confluence cluster built in AWS
• Confluence managed Synchrony via Synchrony-proxy
• Use AWS role for cluster node discovery
• Need outbound proxy to access Internet

So the fix is to add outbound proxy settings to the file synchrony-args.properties that is under the shared-home folder. Something like:

https.proxyHost=proxy.my.domain
https.proxyPort=8080
https.nonProxyHosts='localhost|127.0.0.1|...'

Reference:
https://confluence.atlassian.com/conf615/possible-confluence-and-synchrony-configurations-967338673.html
https://github.com/atlassian/quickstart-atlassian-confluence