Fix validate-cluster.sh for clusters with more than 500 nodes.

cluster/validate-cluster.sh

@@ -98,7 +98,13 @@ while true; do
   #
   # We are assigning the result of kubectl_retry get nodes operation to the res
   # variable in that way, to prevent stopping the whole script on an error.
-  node=$(kubectl_retry get nodes) && res="$?" || res="$?"
+  #
+  # Bash command substitution $(kubectl_...) removes all trailing whitespaces
+  # which are important for line counting.
+  # Use trick from https://unix.stackexchange.com/a/383411 to avoid
+  # newline truncation.
+  node=$(kubectl_retry get nodes --no-headers; ret=$?; echo .; exit "$ret") && res="$?" || res="$?"
+  node="${node%.}"
   if [ "${res}" -ne "0" ]; then
     if [[ "${attempt}" -gt "${last_run:-$MAX_ATTEMPTS}" ]]; then
       echo -e "${color_red} Failed to get nodes.${color_norm}"
@@ -107,8 +113,9 @@ while true; do
       continue
     fi
   fi
-  found=$(($(echo "${node}" | wc -l) - 1))
-  ready=$(($(echo "${node}" | grep -v "NotReady" | wc -l ) - 1))
+  found=$(echo -n "${node}" | wc -l)
+  # Use grep || true so that empty result doesn't return nonzero exit code.
+  ready=$(echo -n "${node}" | grep -c -v "NotReady" || true)
 
   if (( "${found}" == "${EXPECTED_NUM_NODES}" )) && (( "${ready}" == "${EXPECTED_NUM_NODES}")); then
     break