[Improvement][Common] Obtain resource information in the k8s environm… (#14968)

* [Improvement][Common] Obtain resource information in the k8s environment.

* [Improvement][Common] Change the comment

---------

Co-authored-by: 旺阳 <qingwli@cisco.com>

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/KubernetesUtils.java

@@ -24,9 +24,11 @@ import lombok.experimental.UtilityClass;
 @UtilityClass
 public class KubernetesUtils {
 
+    public static final Boolean KUBERNETES_MODE = !StringUtils.isEmpty(System.getenv("KUBERNETES_SERVICE_HOST"))
+            && !StringUtils.isEmpty(System.getenv("KUBERNETES_SERVICE_PORT"));
+
     public boolean isKubernetesMode() {
-        return !StringUtils.isEmpty(System.getenv("KUBERNETES_SERVICE_HOST"))
-                && !StringUtils.isEmpty(System.getenv("KUBERNETES_SERVICE_PORT"));
+        return KUBERNETES_MODE;
     }
 
 }

dolphinscheduler-common/src/main/java/org/apache/dolphinscheduler/common/utils/OSUtils.java

@@ -35,6 +35,7 @@ import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.lang.management.ManagementFactory;
+import java.lang.management.OperatingSystemMXBean;
 import java.lang.management.RuntimeMXBean;
 import java.math.RoundingMode;
 import java.text.DecimalFormat;
@@ -96,16 +97,22 @@ public class OSUtils {
     }
 
     /**
-     * get available physical memory size
+     * get available physical or pod memory size
      * <p>
      * Keep 2 decimal
      *
-     * @return available Physical Memory Size, unit: G
+     * @return Available physical or pod memory size, unit: G
      */
     public static double availablePhysicalMemorySize() {
-        GlobalMemory memory = hal.getMemory();
-        double availablePhysicalMemorySize = memory.getAvailable() / 1024.0 / 1024 / 1024;
+        double availablePhysicalMemorySize;
 
+        if (KubernetesUtils.isKubernetesMode()) {
+            long freeMemory = Runtime.getRuntime().freeMemory();
+            availablePhysicalMemorySize = freeMemory / 1024.0 / 1024 / 1024;
+        } else {
+            GlobalMemory memory = hal.getMemory();
+            availablePhysicalMemorySize = memory.getAvailable() / 1024.0 / 1024 / 1024;
+        }
         DecimalFormat df = new DecimalFormat(TWO_DECIMAL);
         df.setRoundingMode(RoundingMode.HALF_UP);
         return Double.parseDouble(df.format(availablePhysicalMemorySize));
@@ -123,7 +130,13 @@ public class OSUtils {
         long now = System.currentTimeMillis();
         if (now - prevTickTime > 950) {
             // Enough time has elapsed.
-            cpuUsage = processor.getSystemCpuLoadBetweenTicks(prevTicks);
+            if (KubernetesUtils.isKubernetesMode()) {
+                OperatingSystemMXBean operatingSystemMXBean = ManagementFactory.getOperatingSystemMXBean();
+                cpuUsage = operatingSystemMXBean.getSystemLoadAverage();
+            } else {
+                cpuUsage = processor.getSystemCpuLoadBetweenTicks(prevTicks);
+            }
+
             prevTickTime = System.currentTimeMillis();
             prevTicks = processor.getSystemCpuLoadTicks();
         }