When using WordPress in an HA fault-tolerant stack on AWS, you can usually use the same processes and procedures you would use on a single-server WP installation. But, there are some processes that, if adopted, will make using a fault-tolerant WP configuration a little less frustrating.
The first process change we recommend you make is in uploading plugins and themes. For plugins and themes with a lot of small files in their zips, we strongly recommend that you upload these via sFTP. You’re less likely to get timeouts. The EFS (elastic file system) volume has a much higher latency so unzipping a lot of small files can take quite a bit of time. This can cause the web server to time out. Thus, sFTP is the recommended method for uploading plugins and themes.
Of course, if you’re integrating a GIT or other version control process into your workflow then this probably doesn’t matter as much.