New dashboard looking at incorrect datasource

I am new to Grafana (FYI). I installed Grafana, InfluxDB, and collectd. I know collectd is interfacing with InfluxDB fine because I can see system metrics in InfluxDB in the collectd database. In Grafana, I created two datasources, one for a database in InfluxDB I originally created (psu_db) and the other which is for collectd (‘collectd’) database. Next, I loaded the Host Overview dashboard in Grafana and spec’d ‘collectd’ as the data source. All the graphs are empty.

Examining /var/log/messages, I see influxd receiving queries against the psu_db database and not collectd, which may explain why I am not seeing any metrics graphed. However, I double-checked my datasource config for “collectd” and it is referring to the right database in InfluxDB, and the dashboard is referring to collectd and not psu_db as the datasource. So what could be going wrong?