I would like to see an event triggered if a agent does not connect to the Sensu Go backend within a certain timeframe.
Description of steps you’ve taken to attempt to solve the issue
I have added a configuration for the agent, that is expected to connect and can see it if I run sensuctl entity list with “Last seen” set to “N/A”. I have tried specifying the keepalive timeout values. However, they only trigger an event if the agent sent an initial keepalive.
There is no built in way to alert on failed agent connectivity. My suggestion(s) would be either a scripted check script as simple as the one below or a scripted api call to grab entities with a last keepalive value of null while the entity has existed for more than n minutes. Then handling the event alert with your preferred handler.
Possible drawback of the log check approach would be the absence of the error in logs due to a low log level, Please make sure to set the log level to debug while testing.
#!/bin/bash
if journalctl -u sensu-backend | grep -q “websocket connection error”; then
exit 1
else
exit 0
fi