Promtail: use local task dir rather than bind mount

core/metrics/exporters.nomad

@@ -39,16 +39,9 @@ job "exporters" {
 
       config {
         image = "grafana/promtail:2.7.1"
-        args = ["-config.file=/etc/promtail/promtail.yml"]
+        args = ["-config.file=${NOMAD_TASK_DIR}/promtail.yml"]
         ports = ["promtail"]
 
-        # Mount config
-        mount {
-          type = "bind"
-          target = "/etc/promtail/promtail.yml"
-          source = "local/promtail.yml"
-        }
-
         # Bind mount host machine-id and log directories
 
         mount {
@@ -134,7 +127,7 @@ scrape_configs:
       - source_labels: ['__journal_com_hashicorp_nomad_task_name']
         target_label: nomad_task_name
 EOF
-        destination = "local/promtail.yml"
+        destination = "${NOMAD_TASK_DIR}/promtail.yml"
       }
 
       resources {