I can’t find it anywhere either, but I’m looking at a 3.11.4 source image. From the naming I’d bet that this is being used to feed the cassandra.migration_task_wait_in_seconds property. It’s already coded to have a default of 1 second, which matches what you are seeing in the shell script var. The relevant Java source is org.apache.cassandra.service.MigrationManager, line 62.
From: Ben Mills <b...@bitbrew.com> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org> Date: Monday, January 13, 2020 at 1:59 PM To: "user@cassandra.apache.org" <user@cassandra.apache.org> Subject: cassandra_migration_wait Message from External Sender Greetings, We are running Cassandra 3.11.2 in Kubernetes and use a run.sh to set some environment variables and a few other things. This script includes: CASSANDRA_MIGRATION_WAIT="${CASSANDRA_MIGRATION_WAIT:-1}" setting this environment variable to "1". I looked for documentation on this but cannot seem to find it anywhere. Anyone know what this is configuring and what the value implies? Thanks in advance for your help. Ben