A set of collectors that can be used to monitor Apache Tomcat instances.
The following Tomcat related metrics are provided:
If you are running Tomcat in the conventional non-embedded setup we recommended to add the following jars (see
pom.xml) to the
$CATALINA_BASE/lib directory or another directory on the Tomcat
common.loader is important as we need to make sure that all metrics are registered using the same class loader.
Next, rename tomcat_exporter_servlet war file to
metrics.war and add it to the webapps directory of Tomcat. After restart of tomcat you should be able to access metrics via the
If you want servlet response time metrics you can configure the
TomcatServletMetricsFilter by adding it to the $CATALINA_BASE/conf/web.xml as shown below. There is no need to modify already deployed applications.
<filter> <filter-name>ServletMetricsFilter</filter-name> <filter-class>nl.nlighten.prometheus.tomcat.TomcatServletMetricsFilter</filter-class> <async-supported>true</async-supported> <init-param> <param-name>buckets</param-name> <param-value>.01, .05, .1, .25, .5, 1, 2.5, 5, 10, 30</param-value> </init-param> </filter> <filter-mapping> <filter-name>ServletMetricsFilter</filter-name> <url-pattern>/*</url-pattern> </filter-mapping>
For an explanation on histograms and buckets please see the prometheus documentation.
Database response time metrics are only available when using the Tomcat JDBC Pool as this collector uses an interceptor mechanism that is only available for this type of pool.
The interceptor will collect the following metrics:
Configuration is usually done in Tomcat's
<Resource name="jdbc/TestDB" auth="Container" type="javax.sql.DataSource" factory="org.apache.tomcat.jdbc.pool.DataSourceFactory" jdbcInterceptors="nl.nlighten.prometheus.tomcat.TomcatJdbcInterceptor(logFailed=true,logSlow=true,threshold=1000,buckets=.01|.05|.1|1|10,slowQueryBuckets=1|10|30)" username="root" password="password" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/mysql"/>
Configuration options of the interceptor are as shown above and have the following meaning:
- Enabling logFailed and logSlow may lead to a lot of additional metrics., so be careful !!!
- If you are defining your data source on application level (so inside your war), you need to set bindOnInit to ensure that your data source has been initialized before the metrics application starts.
If you run Tomcat in embedded mode, please look at the
AbstractTomcatMetricsTest for an example on how to configure the various exporters when running embedded.
There are canonical examples defined in the class definition Javadoc of the client packages.