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HDFS-7186. Document the "hadoop trace" command. (Masatake Iwasaki via Colin P. McCabe) 

(cherry picked from commit 9196db9a08)
This commit is contained in:
Colin Patrick Mccabe 2014-10-07 11:55:49 -07:00
parent 979b915ecc
commit 2a8f824fb7
2 changed files with 66 additions and 12 deletions
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3
hadoop-common-project/hadoop-common/CHANGES.txt
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@ -11,6 +11,9 @@ Release 2.7.0 - UNRELEASED
HADOOP-11156. DelegateToFileSystem should implement
getFsStatus(final Path f). (Zhihai Xu via wang)
HDFS-7186. Document the "hadoop trace" command. (Masatake Iwasaki via Colin
P. McCabe)
OPTIMIZATIONS
BUG FIXES

75
hadoop-common-project/hadoop-common/src/site/apt/Tracing.apt.vm
View File

@ -46,21 +46,32 @@ public void receiveSpan(Span span);
+----
<property>
<name>hadoop.trace.spanreceiver.classes</name>
<name>hadoop.htrace.spanreceiver.classes</name>
<value>org.htrace.impl.LocalFileSpanReceiver</value>
</property>
<property>
<name>hadoop.local-file-span-receiver.path</name>
<name>hadoop.htrace.local-file-span-receiver.path</name>
<value>/var/log/hadoop/htrace.out</value>
</property>
+----
You can omit package name prefix if you use span receiver bundled with HTrace.
+----
<property>
<name>hadoop.htrace.spanreceiver.classes</name>
<value>LocalFileSpanReceiver</value>
</property>
+----
** Setting up ZipkinSpanReceiver
Instead of implementing SpanReceiver by yourself,
you can use <<<ZipkinSpanReceiver>>> which uses
{{{https://github.com/twitter/zipkin}Zipkin}}
for collecting and dispalying tracing data.
for collecting and displaying tracing data.
In order to use <<<ZipkinSpanReceiver>>>,
you need to download and setup {{{https://github.com/twitter/zipkin}Zipkin}} first.
@ -82,22 +93,63 @@ public void receiveSpan(Span span);
+----
<property>
<name>hadoop.trace.spanreceiver.classes</name>
<value>org.htrace.impl.ZipkinSpanReceiver</value>
<name>hadoop.htrace.spanreceiver.classes</name>
<value>ZipkinSpanReceiver</value>
</property>
<property>
<name>hadoop.zipkin.collector-hostname</name>
<name>hadoop.htrace.zipkin.collector-hostname</name>
<value>192.168.1.2</value>
</property>
<property>
<name>hadoop.zipkin.collector-port</name>
<name>hadoop.htrace.zipkin.collector-port</name>
<value>9410</value>
</property>
+----
** Turning on tracing by HTrace API
In order to turn on Dapper-like tracing,
** Dynamic update of tracing configuration
You can use <<<hadoop trace>>> command to see and update the tracing configuration of each servers.
You must specify IPC server address of namenode or datanode by <<<-host>>> option.
You need to run the command against all servers if you want to update the configuration of all servers.
<<<hadoop trace -list>>> shows list of loaded span receivers associated with the id.
+----
$ hadoop trace -list -host 192.168.56.2:9000
ID CLASS
1 org.htrace.impl.LocalFileSpanReceiver
$ hadoop trace -list -host 192.168.56.2:50020
ID CLASS
1 org.htrace.impl.LocalFileSpanReceiver
+----
<<<hadoop trace -remove>>> removes span receiver from server.
<<<-remove>>> options takes id of span receiver as argument.
+----
$ hadoop trace -remove 1 -host 192.168.56.2:9000
Removed trace span receiver 1
+----
<<<hadoop trace -add>>> adds span receiver to server.
You need to specify the class name of span receiver as argument of <<<-class>>> option.
You can specify the configuration associated with span receiver by <<<-Ckey=value>>> options.
+----
$ hadoop trace -add -class LocalFileSpanReceiver -Chadoop.htrace.local-file-span-receiver.path=/tmp/htrace.out -host 192.168.56.2:9000
Added trace span receiver 2 with configuration hadoop.htrace.local-file-span-receiver.path = /tmp/htrace.out
$ hadoop trace -list -host 192.168.56.2:9000
ID CLASS
2 org.htrace.impl.LocalFileSpanReceiver
+----
** Starting tracing spans by HTrace API
In order to trace,
you will need to wrap the traced logic with <<tracing span>> as shown below.
When there is running tracing spans,
the tracing information is propagated to servers along with RPC requests.
@ -133,7 +185,6 @@ import org.htrace.TraceScope;
+----
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FsShell;
import org.apache.hadoop.hdfs.HdfsConfiguration;
import org.apache.hadoop.tracing.SpanReceiverHost;
import org.apache.hadoop.util.ToolRunner;
import org.htrace.Sampler;
@ -146,8 +197,8 @@ public class TracingFsShell {
FsShell shell = new FsShell();
conf.setQuietMode(false);
shell.setConf(conf);
SpanReceiverHost.getInstance(conf);
int res = 0;
SpanReceiverHost.init(new HdfsConfiguration());
TraceScope ts = null;
try {
ts = Trace.startSpan("FsShell", Sampler.ALWAYS);
@ -165,5 +216,5 @@ public class TracingFsShell {
+----
$ javac -cp `hadoop classpath` TracingFsShell.java
$ HADOOP_CLASSPATH=. hdfs TracingFsShell -put sample.txt /tmp/
$ java -cp .:`hadoop classpath` TracingFsShell -ls /
+----