Fix setting resources in fluentd-gcp plugin

cluster/addons/fluentd-gcp/fluentd-gcp-ds-sa.yaml

+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: fluentd-gcp
+  namespace: kube-system
+  labels:
+    kubernetes.io/cluster-service: "true"
+    addonmanager.kubernetes.io/mode: Reconcile

cluster/addons/fluentd-gcp/fluentd-gcp-ds.yaml

-apiVersion: v1
-kind: ServiceAccount
-metadata:
-  name: fluentd-gcp
-  namespace: kube-system
-  labels:
-    kubernetes.io/cluster-service: "true"
-    addonmanager.kubernetes.io/mode: Reconcile
----
 apiVersion: extensions/v1beta1
 kind: DaemonSet
 metadata:

cluster/gce/gci/configure-helper.sh

@@ -1942,21 +1942,47 @@ function copy-manifests {
 # Fluentd manifest is modified using kubectl, which may not be available at
 # this point. Run this as a background process.
 function wait-for-apiserver-and-update-fluentd {
+  local -r fluentd_gcp_yaml="${1}"
+
+  local modifying_flags=""
+  if [[ -n "${FLUENTD_GCP_MEMORY_LIMIT:-}" ]]; then
+    modifying_flags="${modifying_flags} --limits=memory=${FLUENTD_GCP_MEMORY_LIMIT}"
+  fi
+  local request_resources=""
+  if [[ -n "${FLUENTD_GCP_CPU_REQUEST:-}" ]]; then
+    request_resources="cpu=${FLUENTD_GCP_CPU_REQUEST}"
+  fi
+  if [[ -n "${FLUENTD_GCP_MEMORY_REQUEST:-}" ]]; then
+    if [[ -n "${request_resources}" ]]; then
+      request_resources="${request_resources},"
+    fi
+    request_resources="memory=${FLUENTD_GCP_MEMORY_REQUEST}"
+  fi
+  if [[ -n "${request_resources}" ]]; then
+    modifying_flags="${modifying_flags} --requests=${request_resources}"
+  fi
+
   until kubectl get nodes
   do
     sleep 10
   done
-  kubectl set resources --dry-run --local -f ${fluentd_gcp_yaml} \
-    --limits=memory=${FLUENTD_GCP_MEMORY_LIMIT} \
-    --requests=cpu=${FLUENTD_GCP_CPU_REQUEST},memory=${FLUENTD_GCP_MEMORY_REQUEST} \
-    --containers=fluentd-gcp -o yaml > ${fluentd_gcp_yaml}.tmp
-  mv ${fluentd_gcp_yaml}.tmp ${fluentd_gcp_yaml}
+
+  local -r temp_fluentd_gcp_yaml="${fluentd_gcp_yaml}.tmp"
+  if kubectl set resources --dry-run --local -f ${fluentd_gcp_yaml} ${modifying_flags} \
+      --containers=fluentd-gcp -o yaml > ${temp_fluentd_gcp_yaml}; then
+    mv ${temp_fluentd_gcp_yaml} ${fluentd_gcp_yaml}
+  else
+    (echo "Failed to update fluentd resources. Used manifest:" && cat ${temp_fluentd_gcp_yaml}) >&2
+    rm ${temp_fluentd_gcp_yaml}
+  fi
 }
 
 # Trigger background process that will ultimately update fluentd resource
 # requirements.
 function start-fluentd-resource-update {
-  wait-for-apiserver-and-update-fluentd &
+  local -r fluentd_gcp_yaml="${1}"
+
+  wait-for-apiserver-and-update-fluentd ${fluentd_gcp_yaml} &
 }
 
 # Updates parameters in yaml file for prometheus-to-sd configuration, or
@@ -2091,7 +2117,7 @@ EOF
     local -r fluentd_gcp_yaml="${dst_dir}/fluentd-gcp/fluentd-gcp-ds.yaml"
     update-prometheus-to-sd-parameters ${event_exporter_yaml}
     update-prometheus-to-sd-parameters ${fluentd_gcp_yaml}
-    start-fluentd-resource-update
+    start-fluentd-resource-update ${fluentd_gcp_yaml}
   fi
   if [[ "${ENABLE_CLUSTER_UI:-}" == "true" ]]; then
     setup-addon-manifests "addons" "dashboard"