CHANGELOG-3.3: add "--auto-compaction-mode"

Signed-off-by: Gyuho Lee <[email protected]>

CHANGELOG-3.3.md

@@ -71,6 +71,8 @@ See [code changes](https://github.com/coreos/etcd/compare/v3.2.0...v3.3.0-rc.0)
   - Useful for [bypassing critical APIs when monitoring etcd](https://github.com/coreos/etcd/issues/8060).
 - Add [`--auto-compaction-mode`](https://github.com/coreos/etcd/pull/8123) flag to [support revision-based compaction](https://github.com/coreos/etcd/issues/8098).
 - Change `--auto-compaction-retention` flag to [accept string values](https://github.com/coreos/etcd/pull/8563) with [finer granularity](https://github.com/coreos/etcd/issues/8503).
+  - e.g. `--auto-compaction-mode=periodic --auto-compaction-retention=30m` automatically `Compact` on latest revision every 30-minute.
+  - e.g. `--auto-compaction-mode=revision --auto-compaction-retention=1000` automatically `Compact` on `"latest revision" - 1000` every 5-minute (when latest revision is 30000, compact on revision 29000).
 - Add [`--grpc-keepalive-min-time`, `--grpc-keepalive-interval`, `--grpc-keepalive-timeout`](https://github.com/coreos/etcd/pull/8535) flags to configure server-side keepalive policies.
 - Serve [`/health` endpoint as unhealthy](https://github.com/coreos/etcd/pull/8272) when [alarm (e.g. `NOSPACE`) is raised or there's no leader](https://github.com/coreos/etcd/issues/8207).
   - Define [`etcdhttp.Health`](https://godoc.org/github.com/coreos/etcd/etcdserver/api/etcdhttp#Health) struct with JSON encoder.