Skip to main content

Tomcat Linux


Tomcat server monitoring collect multiple types of metrics like server stats, context stats, jvm stats using Jolokia



Tomcat Plugin is based on Jolokia agent which requires JMX monitoring to be enabled locally.

  • JCMD command must be installed in the machine
  • The JVM must have HotSpot enabled and be a JVM 1.6 or larger.

Access Log Format

Tomcat server access log format needs to be modified to capture all metrics from the access logs, which includes following steps

  • Edit the file $TOMCAT_HOME/conf/server.xml

  • Set log format in “org.apache.catalina.valves.AccessLogValve” class, pattern value to pre-defined “combined” log format or

%h %l %u %t "%r" %s %b %D "%{Referer}i" "%{User-Agent}i"

After changing log pattern to combined or the above mentioned pattern, sample log would look like: - - [30/Jun/2020:13:12:32 +0000] "GET / HTTP/1.1" 200 11286 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36"


sfAgent section provides steps to install and automatically generate plugin configurations. User can also manually add the configuration shown below to config.yaml under /opt/sfagent/ directory

key: <profile key> 
generate_name: true
Name: <unique instance name or will be generated from IP>
appName: <add application name>
projectName: <add project name>
- name: tomcat
enabled: true
interval: 300
username: xxxx
password: xxxx
- tomcatStats
- requestProcessorStats
- jvmStats
- contextStats
- name: tomcat-access
enabled: true
geo_info: true
log_path: /opt/apache-tomcat*/logs/localhost_access_*.txt
ua_parser: false
url_normalizer: false

Tomcat access log options:

  1. Geo-IP: Useful to find geographical location of the client using the IP address. To enable, set the option "geo_info" to true in the above configuration.
  2. User-Agent Analysis: To get the host machine details like browser, Operating system and device by analysis the user-agent. To enable, set the option "ua_parser" to true in the above configuration. If enabled, by default it runs on port 8586.
  3. URL Normalizer (not supported in container deployment): Normalize incoming URL paths. To enable, set the option "url_normalizer" to true in the above configuration. If enabled, by default it runs on port 8587.

Normalization specific configuration is available in /opt/sfagent/normalization/config.yaml which resonate the following,

interval: 300
enabled: true
rules_length_limit: 1000
log_volume: 100000
rules: []

Config Field Description

interval: Normalization algorithm runtime interval.

enabled: Rely on normalization feature for rule generation.

rules_length_limit: Limit over size of generated rules. set the value to -1 for specifying no limit.

log_volume: Limit over number of logs processed. set the value to -1 for specifying no limit.

rules: Rules Generated.

Recommended approach is to run sfagent with dynamic_rule_generation enabled over a period of time. Observe whether rules generated reflect all the web app requests intended to be normalized and if its a true reflection, set enabled flag to false , indicating no further rules will be generated

Default ports used by user-agent analysis and URL Normalizer can be changed respectively with the inclusion of following in config.yaml

uaparserport: port_number
url_normalizer: port_number
  1. Latitude and Longitude are often near the center of population. These values are not precise and should not be used to identify a particular address or household.
  2. User-agent parsing requires high computation power. Recommended to enable only if needed and system have enough CPU resource available.

View Data and Dashboard

Tomcat server metrics plugin=tomcat consists of four document types:

  • Tomcat stats: contain metrics like tomcat sever version, uptime, thread details.
  • Request processor stats: shows request information like processing time, request count, data received and sent.
  • Context stats: contain tomcat context related metrics like hit count, lookup count etc.
  • JVM stats: contain all JVM related metrics used by tomcat server like garbage collection details, memory pools, loaded/unloaded classes etc.

Tomcat access logs come under metrics section on APM dashboard with plugin=tomcat-access and documentType=tomcatAccessLogs

  • Dashboard for this data can be instantiated by Importing dashboard template Tomcat_Server, Tomcat_Access to the application dashboard.