my server info:
centos 7 x64, grafana 8.0.4 enable ngalert feature
prometheus scrape config:
scrape_configs:
- job_name: myserversjob
static_configs:
- targets: ['server1:9100','server2:9100','server3:9100','server4:9100']
Create alert rule on grafana webui:
create query name A with node_filesystem_free_bytes{job=“myserversjob”}
create query name B with node_filesystem_size_bytes{job=“myserversjob”}
create math expr name C with expr: $A/$B<0.2
The data of A and B is ok , and can preview in time series graph, but the value of C is always no data。
Am i do the wrong step?