HDFS-11566. Ozone: Document missing metrics for container operations. Contributed by Yiqun Lin.

hadoop-hdfs-project/hadoop-hdfs/src/site/markdown/Ozonemetrics.md

@@ -0,0 +1,89 @@
+<!---
+  Licensed under the Apache License, Version 2.0 (the "License");
+  you may not use this file except in compliance with the License.
+  You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+  Unless required by applicable law or agreed to in writing, software
+  distributed under the License is distributed on an "AS IS" BASIS,
+  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+  See the License for the specific language governing permissions and
+  limitations under the License. See accompanying LICENSE file.
+-->
+
+
+
+HDFS Ozone Metrics
+===============
+
+<!-- MACRO{toc|fromDepth=0|toDepth=3} -->
+
+Overview
+--------
+
+The container metrics that is used in HDFS Ozone.
+
+### Storage Container Metrics
+
+The metrics for various storage container operations in HDFS Ozone.
+
+Storage container is an optional service that can be enabled by setting
+'ozone.enabled' to true.
+These metrics are only available when ozone is enabled.
+
+Storage Container Metrics maintains a set of generic metrics for all
+container RPC calls that can be made to a datandoe/container.
+
+Along with the total number of RPC calls containers maintain a set of metrics
+for each RPC call. Following is the set of counters maintained for each RPC
+operation.
+
+*Total number of operation* - We maintain an array which counts how
+many times a specific operation has been performed.
+Eg.`NumCreateContainer` tells us how many times create container has been
+invoked on this datanode.
+
+*Number of bytes involved in a specific command* - This is an array that is
+maintained for all operations, but makes sense only for read and write
+operations.
+
+While it is possible to read the bytes in update container, it really makes
+no sense, since no data stream involved. Users are advised to use this
+metric only when it makes sense. Eg. `BytesReadChunk` -- Tells us how
+many bytes have been read from this data using Read Chunk operation.
+
+*Average Latency of each operation* - The average latency of the operation.
+Eg. `LatencyCreateContainerAvgTime` - This tells us the average latency of
+Create Container.
+
+*Quantiles for each of these operations* - The 50/75/90/95/99th percentile
+of these operations. Eg. `CreateContainerNanos60s50thPercentileLatency` --
+gives latency of the create container operations at the 50th percentile latency
+(1 minute granularity). We report 50th, 75th, 90th, 95th and 99th percentile
+for all RPCs.
+
+So this leads to the containers reporting these counters for each of these
+RPC operations.
+
+| Name | Description |
+|:---- |:---- |
+| `NumOps` | Total number of container operations |
+| `CreateContainer` | Create container operation |
+| `ReadContainer` | Read container operation |
+| `UpdateContainer` | Update container operations |
+| `DeleteContainer` | Delete container operations |
+| `ListContainer` | List container operations |
+| `PutKey` | Put key operations |
+| `GetKey` | Get key operations |
+| `DeleteKey` | Delete key operations |
+| `ListKey` | List key operations |
+| `ReadChunk` | Read chunk operations |
+| `DeleteChunk` | Delete chunk operations |
+| `WriteChunk` | Write chunk operations|
+| `ListChunk` | List chunk operations |
+| `CompactChunk` | Compact chunk operations |
+| `PutSmallFile` | Put small file operations |
+| `GetSmallFile` | Get small file operations |
+| `CloseContainer` | Close container operations |
+

hadoop-project/src/site/site.xml

@@ -203,6 +203,7 @@
       <item name="Java API docs" href="api/index.html"/>
       <item name="Unix Shell API" href="hadoop-project-dist/hadoop-common/UnixShellAPI.html"/>
       <item name="Metrics" href="hadoop-project-dist/hadoop-common/Metrics.html"/>
+      <item name="Ozone Metrics" href="hadoop-project-dist/hadoop-hdfs/Ozonemetrics.html"/>
     </menu>
     
     <menu name="Configuration" inherit="top">