returnErr(Error::other(format!("tier mismatch: instance {instance_name} is from tier: '{}', but replicaset {replicaset_name} is from tier: '{}'",tier.name,replicaset.tier)));
returnErr(Error::other(format!("tier mismatch: instance {instance_name} is from tier: '{}', but replicaset {requested_replicaset_name} is from tier: '{}'",tier.name,replicaset.tier)));
}
// FIXME: must make sure the replicaset is not Expelled or ToBeExpelled
// FIXME: must make sure the replicaset's tier is correct