I dont kow if you have a custom trigger or a built in trigger for health test.
Is the health test showing warning or critical or bad ?
either way the test is to find the data locality in the host .
" Make sure that Impala Daemon is co-located with a DataNode, and that the IP address of each Impala Daemon matches the IP address of its co-located DataNode"
Please make sure if you have enabled the below properties in hdfs-site.xml
<property>
<name>dfs.client.read.shortcircuit</name>
<value>true</value>
</property>
<property>
<name>dfs.domain.socket.path</name>
<value>/var/run/hdfs-sockets/dn</value>
</property>
<property>
<name>dfs.client.file-block-storage-locations.timeout.millis</name>
<value>10000</value>
</property>
Reference
https://www.cloudera.com/documentation/enterprise/5-9-x/topics/impala_config_performance.html#config...