PostgreSQL 12 High Availability Cookbook - Third Edition

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It is fairly obvious that the use of port 5500 isn't ideal. Our choice was arbitrary, and, therefore, there's a small amount of potential for misconfiguration in some other part of the application stack; some even expect defaults when possible.

To that end, we encourage the use of multiple HAProxy servers. Modern servers are often deployed as a low-resource virtual system, and proxy nodes are an especially good match for that approach. Proxy software doesn't require much overhead in the way of CPU, RAM, or storage bandwidth, so we can simply create more of them.

Always test HAProxy before introducing too many abstraction elements into a software stack. However, you may find that it's better to create a dedicated HAProxy node ...