JEP 158 (https://openjdk.java.net/jeps/158) says the filesize parameter is the “file size in kb” however that appears to not be the case since when it is set to a value of 20000 you end up with GC logs that are only 20000 bytes in length. Setting the value to 20M produces the desired result of GC log files that are 20MB in size.
This fixes the CollectionsAPIDistributedZkTest.testCoresAreDistributedAcrossNodes test failures. Due to the various tests for exceptional conditions, there were times where the session was not released causing stale data to remain in the policy session cache.
This test too makes assumptions about how replicas are placed. In the legacy assignment strategy, the replica of a given collection are spread equally across all nodes but with the new policy based strategy, all cores across collections are spread out. Therefore the assumptions in this test were wrong. I've changed this test to use the legacy assignment policy because testing the autoAddReplicas feature doesn't have to depend on new replica assignment strategies. This change also fixes a bug in Assign which used "collection" key instead of "cluster" to figure out which strategy to use.
The testNonRetryableRequests test makes an assumption that a collection's replicas are equally distributed among all nodes but with the policy engine it is not true. Instead the policy engine spreads out the cores belonging to all collections equally among all nodes. This is fixed by only creating the collection needed by tests in this class just-in-time.
Previously, the maxShardsPerNode parameter was not allowed on collections when autoscaling policy was configured. Also if an autoscaling policy was configured then the default was to set an unlimited maxShardsPerNode automatically. Now the maxShardsPerNode parameter is always allowed during collection creation and maxShardsPerNode should be set correctly (if required) regardless of whether autoscaling policies are in effect or not. The default value of maxShardsPerNode continues to be 1 as before. It can be set to -1 during collection creation to fall back to the old behavior of unlimited maxShardsPerNode when using autoscaling policy. This patch also fixes PolicyHelper to find the free disk space requirements of a new replica from the leader only if said leader node is alive.
