Tomcat

Plugin: go.d.plugin Module: tomcat

Overview

This collector monitors Tomcat metrics about bandwidth, processing time, threads and more.

It parses the information provided by the Server Status HTTP endpoint.

This collector is supported on all platforms.

This collector supports collecting metrics from multiple instances of this integration, including remote instances.

By default, this Tomcat collector cannot access the server's status page. To enable data collection, you will need to configure access credentials with appropriate permissions.

Default Behavior

Auto-Detection

If the Netdata Agent and Tomcat are on the same host, the collector will attempt to connect to the Tomcat server's status page at http://localhost:8080/manager/status?XML=true.

Limits

The default configuration for this integration does not impose any limits on data collection.

Performance Impact

The default configuration for this integration is not expected to impose a significant performance impact on the system.

Metrics

Metrics grouped by scope.

The scope defines the instance that the metric belongs to. An instance is uniquely identified by a set of labels.

Per Tomcat instance

These metrics refer to the entire monitored application.

This scope has no labels.

Metrics:

Metric	Dimensions	Unit
tomcat.jvm_memory_usage	free, used	bytes

Per jvm memory pool

These metrics refer to the JVM memory pool.

Labels:

Label	Description
mempool_name	Memory Pool name.
mempool_type	Memory Pool type.

Metrics:

Metric	Dimensions	Unit
tomcat.jvm_mem_pool_memory_usage	commited, used, max	bytes

Per connector

These metrics refer to the connector.

Labels:

Label	Description
connector_name	Connector name.

Metrics:

Metric	Dimensions	Unit
tomcat.connector_requests	requests	requests/s
tomcat.connector_bandwidth	received, sent	bytes/s
tomcat.connector_requests_processing_time	processing_time	milliseconds
tomcat.connector_errors	errors	errors/s
tomcat.connector_request_threads	idle, busy	threads

Alerts

There are no alerts configured by default for this integration.

Setup

Prerequisites

Access to Tomcat Status Endpoint

The Netdata Agent needs read-only access to its status endpoint to collect data from the Tomcat server.

You can achieve this by creating a dedicated user named netdata with read-only permissions specifically for accessing the Server Status endpoint.

Once you've created the netdata user, you'll need to configure the username and password in the collector configuration file.

Configuration

File

The configuration file name for this integration is go.d/tomcat.conf.

The file format is YAML. Generally, the structure is:

update_every: 1
autodetection_retry: 0
jobs:
  - name: some_name1
  - name: some_name1

You can edit the configuration file using the edit-config script from the Netdata config directory.

cd /etc/netdata 2>/dev/null || cd /opt/netdata/etc/netdata
sudo ./edit-config go.d/tomcat.conf

Options

The following options can be defined globally: update_every, autodetection_retry.

Config options

Name	Description	Default	Required
update_every	Data collection frequency.	1	no
autodetection_retry	Recheck interval in seconds. Zero means no recheck will be scheduled.	0	no
url	Server URL.	http://127.0.0.1:8080	yes
timeout	HTTP request timeout.	1	no
username	Username for basic HTTP authentication.		no
password	Password for basic HTTP authentication.		no
proxy_url	Proxy URL.		no
proxy_username	Username for proxy basic HTTP authentication.		no
proxy_password	Password for proxy basic HTTP authentication.		no
method	HTTP request method.	POST	no
body	HTTP request body.		no
headers	HTTP request headers.		no
not_follow_redirects	Redirect handling policy. Controls whether the client follows redirects.	no	no
tls_skip_verify	Server certificate chain and hostname validation policy. Controls whether the client performs this check.	no	no
tls_ca	Certification authority that the client uses when verifying the server's certificates.		no
tls_cert	Client TLS certificate.		no
tls_key	Client TLS key.		no

Examples

Basic

A basic example configuration.

jobs:
  - name: local
    url: http://127.0.0.1:8080
    username: John
    password: Doe

Multi-instance

Note: When you define multiple jobs, their names must be unique.

Collecting metrics from local and remote instances.

Config

jobs:
  - name: local
    url: http://127.0.0.1:8080
    username: admin1
    password: hackme1

  - name: remote
    url: http://192.0.2.1:8080
    username: admin2
    password: hackme2

Troubleshooting

Debug Mode

Important: Debug mode is not supported for data collection jobs created via the UI using the Dyncfg feature.

To troubleshoot issues with the tomcat collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

• Navigate to the plugins.d directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the plugins setting under [directories].

  cd /usr/libexec/netdata/plugins.d/

• Switch to the netdata user.

  sudo -u netdata -s

• Run the go.d.plugin to debug the collector:

  ./go.d.plugin -d -m tomcat

Getting Logs

If you're encountering problems with the tomcat collector, follow these steps to retrieve logs and identify potential issues:

• Run the command specific to your system (systemd, non-systemd, or Docker container).
• Examine the output for any warnings or error messages that might indicate issues. These messages should provide clues about the root cause of the problem.

System with systemd

Use the following command to view logs generated since the last Netdata service restart:

journalctl _SYSTEMD_INVOCATION_ID="$(systemctl show --value --property=InvocationID netdata)" --namespace=netdata --grep tomcat

System without systemd

Locate the collector log file, typically at /var/log/netdata/collector.log, and use grep to filter for collector's name:

grep tomcat /var/log/netdata/collector.log

Note: This method shows logs from all restarts. Focus on the latest entries for troubleshooting current issues.

Docker Container

If your Netdata runs in a Docker container named "netdata" (replace if different), use this command:

docker logs netdata 2>&1 | grep tomcat