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-rw-r--r--vnfs/vLB/DNSManager/src/.DS_Storebin0 -> 6148 bytes
-rw-r--r--vnfs/vLB/DNSManager/src/main/.DS_Storebin0 -> 6148 bytes
-rw-r--r--vnfs/vLB/DNSManager/src/main/java/.DS_Storebin0 -> 6148 bytes
-rw-r--r--vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java95
-rw-r--r--vnfs/vLB/DNSManager/src/main/java/FDServer.java161
5 files changed, 256 insertions, 0 deletions
diff --git a/vnfs/vLB/DNSManager/src/.DS_Store b/vnfs/vLB/DNSManager/src/.DS_Store
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diff --git a/vnfs/vLB/DNSManager/src/main/.DS_Store b/vnfs/vLB/DNSManager/src/main/.DS_Store
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index 00000000..d0f5e852
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diff --git a/vnfs/vLB/DNSManager/src/main/java/.DS_Store b/vnfs/vLB/DNSManager/src/main/java/.DS_Store
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diff --git a/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java b/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java
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+++ b/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java
@@ -0,0 +1,95 @@
+
+/*************************************************************************//**
+ *
+ * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ ****************************************************************************/
+
+package main.java;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+public class DNSMembershipManager {
+ /*
+ * Uses Failure Detector (FD) to keep track of the DNS servers currently active.
+ * @param port: the port that the FD service listens for incoming UDP packets
+ * @param timeout: how often the FD checks the status of client processes
+ * @param threshold: number of missing ping messages before declaring a client dead
+ * @param debug: debug mode on/off
+ */
+
+ static Set<String> active = new HashSet<String>();
+
+ @SuppressWarnings("static-access")
+ public static void main(String[] args) throws IOException, InterruptedException {
+ if(args.length != 5) {
+ System.out.println("Missing input parameters");
+ System.out.println("Usage:");
+ System.out.print("\t- java FDServer [public IP address] [port] [timeout (sec)] [threshold] [debug]\n");
+ System.exit(0);
+ }
+
+ // Input parameters: PORT, TIMEOUT, THRESHOLD
+ String IPADDR = args[0];
+ int PORT = Integer.parseInt(args[1]);
+ long TIMEOUT = Long.parseLong(args[2]) * 1000; // convert the FD timeout to milliseconds
+ int THRESHOLD = Integer.parseInt(args[3]);
+ int debug = Integer.parseInt(args[4]);
+ boolean DEBUG;
+ if(debug <= 0)
+ DEBUG = false;
+ else
+ DEBUG = true;
+
+ // Start Failure Detector
+ FDServer fd = new FDServer(IPADDR, PORT, TIMEOUT, THRESHOLD, DEBUG);
+
+ // Check the status of client processes periodically. We use the same timeout value as FD
+ Set<String> active = new HashSet<String>();
+ while(true) {
+ Set<String> alive_this_round = fd.getAliveProcesses();
+ Iterator<String> iter = alive_this_round.iterator();
+ String pid;
+
+ // Check if there is some new DNS active
+ while(iter.hasNext()) {
+ pid = iter.next();
+ if(!active.contains(pid)) {
+ active.add(pid);
+ // Add the new vDNS to the set of vDNS servers
+ String script = new String("bash /opt/FDserver/add_dns.sh " + pid);
+ Runtime.getRuntime().exec(script);
+ if(DEBUG) System.out.println("Adding process " + pid + " to the list of DNSs");
+ }
+ }
+
+ // Remove possible dead DNSs
+ iter = active.iterator();
+ while(iter.hasNext()) {
+ pid = iter.next();
+ if(!alive_this_round.contains(pid)) {
+ iter.remove(); // remove element from the iterator to avoid ConcurrentModificationException
+ // Remove the new vDNS from the set of vDNS servers
+ String script = new String("bash /opt/FDserver/remove_dns.sh " + pid);
+ Runtime.getRuntime().exec(script);
+ if(DEBUG) System.out.println("Removing process " + pid + " from the list of DNSs");
+ }
+ }
+ Thread.currentThread().sleep(TIMEOUT);
+ }
+ }
+}
diff --git a/vnfs/vLB/DNSManager/src/main/java/FDServer.java b/vnfs/vLB/DNSManager/src/main/java/FDServer.java
new file mode 100644
index 00000000..4b64c584
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/main/java/FDServer.java
@@ -0,0 +1,161 @@
+
+/*************************************************************************//**
+ *
+ * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ ****************************************************************************/
+
+package main.java;
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+/*
+ * Server-side Failure Detector (FD) implementation.
+ * @param port: the port that the FD service listens for incoming UDP packets
+ * @param timeout: how often the FD checks the status of client processes
+ * @param threshold: number of missing ping messages before declaring a client dead
+ * @param debug: debug mode on/off
+ */
+
+public class FDServer implements Runnable {
+ // Input parameters
+ private String IP_ADDR;
+ private int PORT;
+ private long TIMEOUT;
+ private int THRESHOLD;
+ private boolean DEBUG;
+
+ // Data structures that store information about alive processes, processes alive/dead this round
+ private Map<String, Integer> alive = new ConcurrentHashMap<String, Integer>(); // Key: process IP address; Value: # consecutive missed pings
+ private Set<String> alive_this_round = ConcurrentHashMap.newKeySet(); // Needs to be synchronized because it is accessed by multiple threads
+ private Set<String> dead = new HashSet<String>();
+
+ public FDServer(String ip_addr, int port, long timeout, int threshold, boolean debug) throws IOException {
+ IP_ADDR = ip_addr;
+ PORT = port;
+ TIMEOUT = timeout;
+ THRESHOLD = threshold;
+ DEBUG = debug;
+ (new Thread(this)).start();
+ }
+
+ @Override
+ public void run() {
+ try {
+ runFD();
+ } catch (IOException e) {
+ e.printStackTrace();
+ }
+ }
+
+ private void runFD() throws IOException {
+ // Check the status of client processes periodically
+ TimerTask timer = new TimerTask() {
+ public void run() {
+ checkClientStatus();
+ }
+ };
+ new Timer().scheduleAtFixedRate(timer, 0, TIMEOUT);
+
+ // Define a DatagramSocket object for receiving incoming UDP packets
+ @SuppressWarnings("resource")
+ DatagramSocket sock = new DatagramSocket(PORT);
+ byte[] buffer = new byte[256];
+
+ // Wait for incoming PING messages from remote clients
+ while(true) {
+ DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
+ sock.receive(packet);
+ String[] content = new String(packet.getData()).trim().split(":"); // Remove leading and trailing spaces
+ String msg_type = content[0];
+ String pid = content[1];
+ // Process only PING UDP packets
+ if(msg_type.equals("PING")) {
+ String ip = packet.getAddress().getHostAddress();
+ alive_this_round.add(pid);
+ if(DEBUG) System.out.println("Keep-alive message received from process " + pid + " (sender IP Address: " + ip +")");
+ sendReplyMessage(packet.getAddress());
+ }
+ else {
+ if(DEBUG) System.out.println("The received message is not a PING. Received content: " + content);
+ }
+ }
+ }
+
+ private void sendReplyMessage(InetAddress address) throws IOException {
+ DatagramSocket sock = new DatagramSocket();
+ // Allocate buffer for the PING message
+ String content = "PONG:" + IP_ADDR;
+ byte[] buffer = content.getBytes();
+ // Sent a PONG message
+ DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, PORT);
+ sock.send(packet);
+ sock.close();
+ }
+
+ // Update the list of processes that are alive
+ private void checkClientStatus() {
+ if(DEBUG) System.out.println("/================================/");
+ if(DEBUG) System.out.println("Update status of remote processes");
+ // Check if a process alive the previous round is still alive
+ // Otherwise increment its counter
+ Set<String> alive_processes = alive.keySet();
+ Iterator<String> iter = alive_processes.iterator();
+ while(iter.hasNext()) {
+ String process = iter.next();
+ if(!alive_this_round.contains(process)) {
+ int counter = alive.get(process) + 1;
+ alive.put(process, counter);
+ if(DEBUG) System.out.println("Process " + process + " hasn't sent a message " + counter + " time(s) in a row");
+ // If the number of consecutive missed ping messages reached the threshold,
+ // then assume the process to be dead
+ if(counter == THRESHOLD) {
+ dead.add(process);
+ if(DEBUG) System.out.println("Process " + process + " is dead");
+ }
+ }
+ }
+
+ // Processes alive this round
+ iter = alive_this_round.iterator();
+ while(iter.hasNext()) {
+ String process = iter.next();
+ alive.put(process, 0);
+ if(DEBUG) System.out.println("Process " + process + " is alive this round");
+ }
+
+
+ // Remove dead processes
+ iter = dead.iterator();
+ while(iter.hasNext()) {
+ String process = iter.next();
+ if(alive.containsKey(process))
+ alive.remove(process);
+ if(DEBUG) System.out.println("Process " + process + " is removed from the list of alive processes");
+ }
+
+ // Cleanup
+ alive_this_round.clear();
+ dead.clear();
+ if(DEBUG) System.out.println();
+ }
+
+ // Return the set of alive processes to up-stream applications
+ public Set<String> getAliveProcesses() {
+ return alive.keySet();
+ }
+}