HADOOP-13839. Fix outdated tracing documentation. Contributed by Elek, Marton.
This commit is contained in:
Masatake Iwasaki
parent
a3f4ee53c8
commit
04ccb1bec5
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@ -107,6 +107,9 @@ Release 2.7.4 - UNRELEASED
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HADOOP-11859. PseudoAuthenticationHandler fails with httpcomponents v4.4.
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(Eugene Koifman via jitendra)
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HADOOP-13839. Fix outdated tracing documentation.
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(Elek, Marton via iwasakims)
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Release 2.7.3 - 2016-08-25
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INCOMPATIBLE CHANGES
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@ -12,6 +12,7 @@
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limitations under the License. See accompanying LICENSE file.
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-->
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Enabling Dapper-like Tracing in Hadoop
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======================================
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@ -24,7 +25,8 @@ Enabling Dapper-like Tracing in Hadoop
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* [Dynamic update of tracing configuration](#Dynamic_update_of_tracing_configuration)
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* [Starting tracing spans by HTrace API](#Starting_tracing_spans_by_HTrace_API)
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* [Sample code for tracing](#Sample_code_for_tracing)
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Dapper-like Tracing in Hadoop
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-----------------------------
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@ -37,14 +39,14 @@ Setting up tracing is quite simple, however it requires some very minor changes
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### Samplers
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Configure the samplers in `core-site.xml` property: `hadoop.htrace.sampler`.
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Configure the samplers in `core-site.xml` property: `dfs.htrace.sampler`.
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The value can be NeverSampler, AlwaysSampler or ProbabilitySampler.
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NeverSampler: HTrace is OFF for all spans;
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AlwaysSampler: HTrace is ON for all spans;
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ProbabilitySampler: HTrace is ON for some percentage% of top-level spans.
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<property>
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<name>hadoop.htrace.sampler</name>
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<name>dfs.htrace.sampler</name>
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<value>NeverSampler</value>
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</property>
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@ -61,18 +63,18 @@ by putting a comma separated list of the fully-qualified class name of classes i
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in `core-site.xml` property: `hadoop.htrace.spanreceiver.classes`.
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<property>
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<name>hadoop.htrace.spanreceiver.classes</name>
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<name>dfs.htrace.spanreceiver.classes</name>
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<value>org.apache.htrace.impl.LocalFileSpanReceiver</value>
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</property>
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<property>
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<name>hadoop.htrace.local-file-span-receiver.path</name>
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<name>dfs.htrace.local-file-span-receiver.path</name>
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<value>/var/log/hadoop/htrace.out</value>
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</property>
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You can omit package name prefix if you use span receiver bundled with HTrace.
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<property>
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<name>hadoop.htrace.spanreceiver.classes</name>
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<name>dfs.htrace.spanreceiver.classes</name>
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<value>LocalFileSpanReceiver</value>
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</property>
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@ -83,30 +85,32 @@ you can use `ZipkinSpanReceiver` which uses
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[Zipkin](https://github.com/twitter/zipkin) for collecting and displaying tracing data.
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In order to use `ZipkinSpanReceiver`,
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you need to download and setup [Zipkin](https://github.com/twitter/zipkin) first.
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you need to download and setup [Zipkin](https://github.com/twitter/zipkin) first. With docker you can start an experimental zipkin server with the following command.
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```
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docker run -d -p 9411:9411 -p 9410:9410 openzipkin/zipkin
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```
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you also need to add the jar of `htrace-zipkin` to the classpath of Hadoop on each node.
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Here is example setup procedure.
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The easiest way to achieve this is downloading the binary jars from maven central add put it to the hadoop lib directory.
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$ git clone https://github.com/cloudera/htrace
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$ cd htrace/htrace-zipkin
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$ mvn compile assembly:single
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$ cp target/htrace-zipkin-*-jar-with-dependencies.jar $HADOOP_HOME/share/hadoop/common/lib/
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$ wget http://repo1.maven.org/maven2/org/apache/thrift/libthrift/0.9.0/libthrift-0.9.0.jar -O $HADOOP_HOME/share/hadoop/common/lib/libthrift-0.9.0.jar
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$ wget http://repo1.maven.org/maven2/org/apache/htrace/htrace-zipkin/3.1.0-incubating/htrace-zipkin-3.1.0-incubating.jar -O $HADOOP_HOME/share/hadoop/common/lib/htrace-zipkin-3.1.0-incubating.jar
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The sample configuration for `ZipkinSpanReceiver` is shown below.
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By adding these to `core-site.xml` of NameNode and DataNodes, `ZipkinSpanReceiver` is initialized on the startup.
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You also need this configuration on the client node in addition to the servers.
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<property>
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<name>hadoop.htrace.spanreceiver.classes</name>
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<name>dfs.htrace.spanreceiver.classes</name>
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<value>ZipkinSpanReceiver</value>
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</property>
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<property>
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<name>hadoop.htrace.zipkin.collector-hostname</name>
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<name>dfs.htrace.zipkin.collector-hostname</name>
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<value>192.168.1.2</value>
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</property>
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<property>
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<name>hadoop.htrace.zipkin.collector-port</name>
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<name>dfs.htrace.zipkin.collector-port</name>
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<value>9410</value>
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</property>
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@ -136,8 +140,8 @@ You need to run the command against all servers if you want to update the config
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You need to specify the class name of span receiver as argument of `-class` option.
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You can specify the configuration associated with span receiver by `-Ckey=value` options.
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$ hadoop trace -add -class LocalFileSpanReceiver -Chadoop.htrace.local-file-span-receiver.path=/tmp/htrace.out -host 192.168.56.2:9000
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Added trace span receiver 2 with configuration hadoop.htrace.local-file-span-receiver.path = /tmp/htrace.out
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$ hadoop trace -add -class LocalFileSpanReceiver -Clocal-file-span-receiver.path=/tmp/htrace.out -host 192.168.56.2:9000
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Added trace span receiver 2 with configuration local-file-span-receiver.path = /tmp/htrace.out
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$ hadoop trace -list -host 192.168.56.2:9000
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ID CLASS
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@ -159,7 +163,7 @@ In addition, you need to initialize `SpanReceiver` once per process.
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...
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SpanReceiverHost.getInstance(new HdfsConfiguration());
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SpanReceiverHost.get(new HdfsConfiguration(), "dfs");
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...
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@ -189,7 +193,7 @@ which start tracing span before invoking HDFS shell command.
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FsShell shell = new FsShell();
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conf.setQuietMode(false);
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shell.setConf(conf);
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SpanReceiverHost.getInstance(conf);
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SpanReceiverHost.get(conf, "dfs");
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int res = 0;
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TraceScope ts = null;
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try {
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@ -207,3 +211,5 @@ You can compile and execute this code as shown below.
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$ javac -cp `hadoop classpath` TracingFsShell.java
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$ java -cp .:`hadoop classpath` TracingFsShell -ls /
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The configuration prefix for the client-side htrace configuration is defined in the SpanReceiverHost.get call. In the case above you should use the dfs prefix as on the server side. (*dfs*.htrace…. configuration values)
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