Introducing Watchdog Custom Alerts: Monitor Anything on Your Servers, For Free

We’re pleased to now introduce Watchdog Custom Alerts, part of our Watchdog 2.0 release. Where Watchdog’s Essential Alerts™ automatically monitor vital server metrics, Custom Alerts cover everything else. With Custom Alerts, the possibilities for monitoring key indicators for maintaining uptime just became limitless.

Watchdog, our free-forever server monitor, already notifies you of all your systems’ vitals and health metrics with built-in zero-config Essential Alerts™. These alert on CPU, swap space, memory, ulimits, VM steal time and more.

“Custom Alerts can be configured to monitor apps metrics, IP blacklists, cron jobs — any arbitrary thing,” says Keilan Jackson, our senior engineer. “It’s also easy to migrate your Nagios scripts to instead utilize Watchdog Custom Alerts.”

With Custom Alerts, Watchdog detects changes in a directory and sends an alert when a file is created or removed from the directory. So when a file is created, an alert will be created with the filename of the file as the title, and the contents of the file as the body. When the file is removed, the alert will be resolved.

How We’re Using Watchdog Custom Alerts to Improve Blue Matador’s Uptime

Watchdog uses Elasticsearch in our stack to provide fast and reliable search results for Lumberjack log entries. One known issue with Elasticsearch is that performance can degrade when there are too many indices.

Fortunately, one of the Watchdog Custom Alerts we use gives us peace of mind, is just a short script running on a cron job that simply checks if our elasticsearch clusters have grown too big. Watchdog Custom Alerts allow us to simply put a file in a directory to trigger an alert on anything, and remove it when the issue is resolved.

Here is the simple script we use to check for Elasticsearch indices on an Ubuntu server:


SIZE=$(curl -s "http://localhost:9200/_cat/indices" | wc -l)


if [[ "$SIZE" -gt 10000 ]]; then

    echo "We have too many indices. Currently at $SIZE" | tee $FILE


    rm -f $FILE


This runs on a cron job every minute and is a quick and simple way to set up a Custom Alert and augment the system vital monitoring that Watchdog already provides in our Elasticsearch cluster.

Try Watchdog Custom Alerts Now

We made our Watchdog product free forever because we want to help system admins get ahead of the firefighting curve. Our founders spent years doing on-call DevOps monitoring, day and night. So we get the frustration of fighting fires all the time, always balancing the need to fix production, add more monitoring, and do more of the “real” DevOps work you were hired to do.

You can install Watchdog on your servers right now by creating a free Blue Matador account and and installing on your Linux or Windows servers. No credit card is needed because we really mean it when we say Watchdog is free forever.

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Blue Matador Staff


We began with the goal of making monitoring truly proactive — not reactive. At Blue Matador, we provide peace of mind for DevOps professionals by enabling them to proactively monitor their infrastructure for the first time.