d2s_monitoring_spec.md

+# D2Sphere Monitoring Endpoint Spec
+
+* REST Call without Auth
+
+
+## Device Server
+needed Values:
+* devices Server specific
+  * state OK : [true,false]
+  * number registred devices : [number(long)]
+  * number activated devices : [number(long)]
+  * number online devices : [number(long)]
+  * number critical devices : [number(long)]
+
+* OS specific
+  * RAM total : [number MB]
+  * RAM free : [number MB]
+  * RAM used : [number MB]
+  * HDD total : [number MB]
+  * HDD free : [number MB]
+  * HDD used : [number MB]
+  * LOAD total : [number MB]
+  * LOADfree : [number MB]
+  * LOAD used : [number MB]
+
+``
+public class Main {
+  public static void main(String[] args) {
+    /* Total number of processors or cores available to the JVM */
+    System.out.println("Available processors (cores): " + 
+        Runtime.getRuntime().availableProcessors());
+
+    /* Total amount of free memory available to the JVM */
+    System.out.println("Free memory (bytes): " + 
+        Runtime.getRuntime().freeMemory());
+
+    /* This will return Long.MAX_VALUE if there is no preset limit */
+    long maxMemory = Runtime.getRuntime().maxMemory();
+    /* Maximum amount of memory the JVM will attempt to use */
+    System.out.println("Maximum memory (bytes): " + 
+        (maxMemory == Long.MAX_VALUE ? "no limit" : maxMemory));
+
+    /* Total memory currently available to the JVM */
+    System.out.println("Total memory available to JVM (bytes): " + 
+        Runtime.getRuntime().totalMemory());
+
+    /* Get a list of all filesystem roots on this system */
+    File[] roots = File.listRoots();
+
+    /* For each filesystem root, print some info */
+    for (File root : roots) {
+      System.out.println("File system root: " + root.getAbsolutePath());
+      System.out.println("Total space (bytes): " + root.getTotalSpace());
+      System.out.println("Free space (bytes): " + root.getFreeSpace());
+      System.out.println("Usable space (bytes): " + root.getUsableSpace());
+    }
+  }
+}
+``
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