Tomcat

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Tomcat metrics can be collected by using DDTrace. The flow of the collected data is as follows: Tomcat -> DDTrace -> DataKit(StatsD).

You can see that DataKit has already integrated the StatsD server, and DDTrace collects Tomcat metric data and reports it to DataKit using StatsD protocol.

Configuration¶

Preconditions¶

• Already tested Tomcat version:
  • 11.0.0
  • 10.1.10
  • 9.0.76
  • 8.5.90

DDtrace Configuration¶

• Download dd-java-agent.jar, see here;

• DataKit configuration:

See the configuration of StatsD.

Restart DataKit to make configuration take effect.

• Tomcat configuration:

Create the file setenv.sh under /usr/local/tomcat/bin and give it execute permission, then write the following:

export CATALINA_OPTS="-javaagent:dd-java-agent.jar \
                      -Ddd.jmxfetch.enabled=true \
                      -Ddd.jmxfetch.statsd.host=${DATAKIT_HOST} \
                      -Ddd.jmxfetch.statsd.port=${DATAKIT_STATSD_HOST} \
                      -Ddd.jmxfetch.tomcat.enabled=true"

The parameters are described below:

• javaagent: Fill in the full path to dd-java-agent.jar;
• Ddd.jmxfetch.enabled: Fill in true, which means the DDTrace collection function is enabled;
• Ddd.jmxfetch.statsd.host: Fill in the network address that DataKit listens to. No port number is included;
• Ddd.jmxfetch.statsd.port: Fill in the port number that DataKit listens to. Usually 8125, as determined by the DataKit side configuration;
• Ddd.jmxfetch.tomcat.enabled: Fill in true, which means the Tomcat collect function of DDTrace is enabled. When enabled, the metrics set named tomcat will showing up;

Restart DataKit to make configuration take effect.

Metric¶

There will be two metrics set, one for JVM's metrics, and the other for tomcat, only tomcat is shown below.

For all of the following data collections, the global election tags will be added automatically, we can add extra tags in [inputs.tomcat.tags] if needed:

 [inputs.statsd.tags]
  # some_tag = "some_value"
  # more_tag = "some_other_value"
  # ...

tomcat¶

Log Collection¶

If you want to collect Tomcat logs, you need to enable the file collection function. You can write the absolute path to the Tomcat log file in logging.conf. For example:

[[inputs.logging]]
  logfiles = [
    "/path_to_tomcat/logs/*",
  ]

  source = "tomcat"

After the changes are made, restart DataKit to make the configuration take effect.

Field Description¶

• Access Log

Log sample:

0:0:0:0:0:0:0:1 - admin [24/Feb/2015:15:57:10 +0530] "GET /manager/images/tomcat.gif HTTP/1.1" 200 2066

The list of cut fields is as follows:

• Catalina / Host-manager / Localhost / Manager Log

log example:

06-Sep-2021 22:33:30.513 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Xmx256m

the list of cut fields is as follows:

Jolokia¶

Deprecated, removed in new version {#jolokia}

Config¶

Preconditions¶

• Already tested version:
  • 9
  • 8

Download Jolokia, rename it to jolokia.war, and place it in tomcat's webapps directory. You can also get the jolokia war package from the data directory under the DataKit installation directory. Edit tomcat-users.xml in tomcat's conf directory and add the user whose role is jolokia.

Take apache-tomcat-9.0.45 as an example (the username and password of the jolokia user in the example must be modified) :

$ cd apache-tomcat-9.0.45/

$ export tomcat_dir=`pwd`

$ wget https://search.maven.org/remotecontent?filepath=org/jolokia/jolokia-war/1.6.2/jolokia-war-1.6.2.war \
-O $tomcat_dir/webapps/jolokia.war

$ vim $tomcat_dir/conf/tomcat-users.xml

 37 <!--
 38   <role rolename="tomcat"/>
 39   <role rolename="role1"/>
 40   <user username="tomcat" password="<must-be-changed>" roles="tomcat"/>
 41   <user username="both" password="<must-be-changed>" roles="tomcat,role1"/>
 42   <user username="role1" password="<must-be-changed>" roles="role1"/>
 43 -->
 44   <role rolename="jolokia"/>
 45   <user username="jolokia_user" password="secPassWd@123" roles="jolokia"/>
 46
 47 </tomcat-users>


$ $tomcat_dir/bin/startup.sh

 ...
 Tomcat started.

Go to http://localhost:8080/jolokia to see if the configuration was successful.

Configuration¶

[[inputs.tomcat]]
  ### Tomcat user(rolename="jolokia"). For example:
  # username = "jolokia_user"
  # password = "secPassWd@123"

  # response_timeout = "5s"

  urls = ["http://localhost:8080/jolokia"]

  ### Optional TLS config
  # tls_ca = "/var/private/ca.pem"
  # tls_cert = "/var/private/client.pem"
  # tls_key = "/var/private/client-key.pem"
  # insecure_skip_verify = false

  ### Monitor Interval
  # interval = "15s"

  ## Set true to enable election
  # election = true

  # [inputs.tomcat.log]
  # files = []
  # #grok pipeline script path
  # pipeline = "tomcat.p"

  [inputs.tomcat.tags]
  # some_tag = "some_value"
  # more_tag = "some_other_value"
  # ...

  ### Tomcat metrics
  [[inputs.tomcat.metric]]
    name     = "tomcat_global_request_processor"
    mbean    = '''Catalina:name="*",type=GlobalRequestProcessor'''
    paths    = ["requestCount","bytesReceived","bytesSent","processingTime","errorCount"]
    tag_keys = ["name"]

  [[inputs.tomcat.metric]]
    name     = "tomcat_jsp_monitor"
    mbean    = "Catalina:J2EEApplication=*,J2EEServer=*,WebModule=*,name=jsp,type=JspMonitor"
    paths    = ["jspReloadCount","jspCount","jspUnloadCount"]
    tag_keys = ["J2EEApplication","J2EEServer","WebModule"]

  [[inputs.tomcat.metric]]
    name     = "tomcat_thread_pool"
    mbean    = "Catalina:name=\"*\",type=ThreadPool"
    paths    = ["maxThreads","currentThreadCount","currentThreadsBusy"]
    tag_keys = ["name"]

  [[inputs.tomcat.metric]]
    name     = "tomcat_servlet"
    mbean    = "Catalina:J2EEApplication=*,J2EEServer=*,WebModule=*,j2eeType=Servlet,name=*"
    paths    = ["processingTime","errorCount","requestCount"]
    tag_keys = ["name","J2EEApplication","J2EEServer","WebModule"]

  [[inputs.tomcat.metric]]
    name     = "tomcat_cache"
    mbean    = "Catalina:context=*,host=*,name=Cache,type=WebResourceRoot"
    paths    = ["hitCount","lookupCount"]
    tag_keys = ["context","host"]
    tag_prefix = "tomcat_"

Measurement¶

For all of the following data collections, a global tag named host is appended by default (the tag value is the host name of the DataKit), or other tags can be specified in the configuration through [inputs.tomcat.tags]:

 [inputs.tomcat.tags]
  # some_tag = "some_value"
  # more_tag = "some_other_value"
  # ...

tomcat_global_request_processor¶

tomcat_jsp_monitor¶

tomcat_thread_pool¶

tomcat_servlet¶

tomcat_cache¶

Log Collection¶

To collect Tomcat logs, open files in tomcat.conf and write to the absolute path of the Tomcat log file. For example:

  [inputs.tomcat.log]
    files = ["/path_to_tomcat/logs/*"]

After log collection is turned on, logs with tomcat as the log source will be generated by default.

Field Description¶

• Access Log

Log sample:

0:0:0:0:0:0:0:1 - admin [24/Feb/2015:15:57:10 +0530] "GET /manager/images/tomcat.gif HTTP/1.1" 200 2066

The list of cut fields is as follows:

• Catalina / Host-manager / Localhost / Manager Log

Log example:

06-Sep-2021 22:33:30.513 INFO [main] org.apache.catalina.startup.VersionLoggerListener.log Command line argument: -Xmx256m

the list of cut fields is as follows: