Till now, we have seen that there are various metrics contexts such as JVM, DFS, and RPC. Let's look at them and explore some of the examples, depicting what each context looks like and what it logs:
JVM context: The JVM context contains stats about JVM memory, threads, heap memory, and so on:
jvm.metrics: hostName=dn1.cluster1.com, processName=DataNode, sessionId=,logError=0,logFatal=0,logInfo=159,logWarn=0, memHeapCommittedM=9.4,memHeapUsedM=12.63,memNonHeapCommittedM=28.75,memNonHeapUsedM=19.7356,threadsBlocked=0, threadsNew=0, threadsRunnable=3, threadsTerminated=0, threadsTimedWaiting=2, threadsWaiting=1
DFS context: The DFS context stats talk about the namenode files, capacity, blocks, and so on:
dfs.FSNamesystem: hostName=nn1.cluster1.com, sessionId=, BlocksTotal=440, CapacityRemainingGB=100, CapacityTotalGB=254, CapacityUsedGB=0, FilesTotal=160, PendingReplicationBlocks=0, ScheduledReplicationBlocks=0, TotalLoad=1, UnderReplicatedBlocks=20
Mapred context...