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Diffstat (limited to 'vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java')
-rw-r--r-- | vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java b/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java new file mode 100644 index 00000000..a597f3e5 --- /dev/null +++ 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); + } + } +} |