title: multiple values from grafana variable in prometheus query
body: <p>We have a situation where we need to select the multiple values (instances/servers) from grafana variable field, and multiple values needs to passed to the Prometheus query using some regex, so that i can see selected hosts metrics in single graph. but i am not able to make it work. Can someone please help me with this. </p>
  
  <p>lets take an example , if i select multiples values host1,host2,host3 and then the query should be looks something like this node_load1(instance="host1", instance="host2" , instance="host3").</p>
  
  <p>Hope i made it clear my question. </p>
  
  <p>Thanks in well advance. </p>