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Extend metrics

When you need a metric that’s not present in the default list of node_exporter metrics you may be able to use the textfile collector. The textfile collector allows exporting of statistics from batch jobs. It can also be used to export static metrics, such as what role a machine has.

Enable the textfile collector

The collector is enabled by default. The following folders are used for different resolutions:

Resolution Folder
High /usr/local/percona/pmm2/collectors/textfile-collector/high-resolution
Medium /usr/local/percona/pmm2/collectors/textfile-collector/medium-resolution
Low /usr/local/percona/pmm2/collectors/textfile-collector/low-resolution

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The exporter parses all files in these directories that match the filename wildcard expression *.prom using a simple text-based exposition format. Metrics are stored on the PMM Server-side with additional labels related to this Node.

Examples of shell commands for custom metrics

To statically set roles for a machine using labels:

echo 'node_role{role="my_monitored_server_1"} 1' > /usr/local/percona/pmm2/collectors/textfile-collector/low-resolution/node_role.prom

Here’s an example of a cron job that automatically pushes logged-in users:

$ cat /etc/cron.d/loggedin_users
*/1 * * * *     root    /usr/bin/who | /usr/bin/wc -l | sed -ne 's/^/node_loggedin_users /p' > /usr/local/percona/pmm2/collectors/textfile-collector/high-resolution/node_users.prom

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