Note how to use all namespaces in kube_inventory (influxdata#5416)

plugins/inputs/kube_inventory/README.md

@@ -29,7 +29,7 @@ avoid cardinality issues:
   ## URL for the Kubernetes API
   url = "https://127.0.0.1"
 
-  ## Namespace to use
+  ## Namespace to use. Set to "" to use all namespaces.
   # namespace = "default"
 
   ## Use bearer token for authorization. ('bearer_token' takes priority)
@@ -216,7 +216,7 @@ The persistentvolumeclaim "phase" is saved in the `phase` tag with a correlated
 
 ```
 kubernetes_configmap,configmap_name=envoy-config,namespace=default,resource_version=56593031 created=1544103867000000000i 1547597616000000000
-kubernetes_daemonset
+kubernetes_daemonset,daemonset_name=telegraf,namespace=logging number_unavailable=0i,desired_number_scheduled=11i,number_available=11i,number_misscheduled=8i,number_ready=11i,updated_number_scheduled=11i,created=1527758699000000000i,generation=16i,current_number_scheduled=11i 1547597616000000000
 kubernetes_deployment,deployment_name=deployd,namespace=default replicas_unavailable=0i,created=1544103082000000000i,replicas_available=1i 1547597616000000000
 kubernetes_node,node_name=ip-172-17-0-2.internal allocatable_pods=110i,capacity_memory_bytes=128837533696,capacity_pods=110i,capacity_cpu_cores=16i,allocatable_cpu_cores=16i,allocatable_memory_bytes=128732676096 1547597616000000000
 kubernetes_persistentvolume,phase=Released,pv_name=pvc-aaaaaaaa-bbbb-cccc-1111-222222222222,storageclass=ebs-1-retain phase_type=3i 1547597616000000000

plugins/inputs/kube_inventory/kube_state.go

@@ -38,7 +38,7 @@ var sampleConfig = `
   ## URL for the Kubernetes API
   url = "https://127.0.0.1"
 
-  ## Namespace to use
+  ## Namespace to use. Set to "" to use all namespaces.
   # namespace = "default"
 
   ## Use bearer token for authorization. ('bearer_token' takes priority)