Deployer.md

Deployer

Working

---

Start Command

Socket Connection With node Manager

• Requests for Node list

  • Stand Alone Node
  • Shared Node

  def request_nodes(msg_type, main_client_sock) :
      if(msg_type == "shared") :
              msg = "deployer node_list"
      else :
              msg = "deployer new_node"
  
      main_client_sock.send(msg.encode())

• Calculate Load & Find best Possible Node to deploy Application

  • Get Statistics

    ssh_util class

    class ssh_util():
    
        def connect(self):
        "Login to the remote server"
    				
            self.client = paramiko.SSHClient()
            self.client.set_missing_host_key_policy(paramiko.AutoAddPolicy())
            
            self.client.connect(
    						hostname=self.host, 
    						username=self.username, 
    						password=self.password, 
    						allow_agent=False,
    						look_for_keys=False
    				)
    		
    
        def execute_command(self,commands, vm_ip, vm_username):
        """Execute a command on the remote host.Return a tuple containing
        an integer status and a two strings, the first containing stdout
        and the second containing stderr from the command."""
    
            if self.connect():
                stdin, stdout, stderr = self.client.exec_command(
                                            command,
                                            timeout=10
                                        )
    
            self.ssh_output = stdout.read()

    ssh_ret_val contains All statistics about particular node

    ssh_util_obj = ssh_util()
    ssh_ret_flag, ssh_ret_val = ssh_util_obj.execute_command(
                                    ["vmstat -s"], 
                                    vm_ip, 
                                    username
                                )
    
    total_memory = ssh_ret_val
    used_memory = ssh_ret_val

  • Get Statistics

    ssh_ret_flag, ssh_ret_val = ssh_util_obj.execute_command(
    
        ["echo $[100-$(vmstat 1 2|tail -1|awk '{print $15}')]"], 
        vm_ip, 
        username
    )
    
    cpu_usage = ssh_ret_val

  • Calculate Load

    def calculate_load(used_memory,total_memory, cpu_usage):
    
        ram_usage = used_memory/total_memory * 100
        load = (2 * cpu_usage * ram_usage) / (cpu_usage + ram_usage) 
        
        return load

• Perform Operation on Best Node

  • Run app

    def perform_action_app( selected_node_addr, app_instance_id, 
    												app_run_type, kill = False) :
    	
        file_path = get_application_file_path(app_instance_id)
    
        msg = "start_app:" + app_instance_id + \
                    ":bash " + file_path + \
                    " " + app_instance_id + \
                    " " + file_path.rsplit('/',1)[0]
    
        client_sock.send(msg.encode()) 

• DB Update

  • Insert Application_Instance_Id to DB

    job_id = uuid.uuid4()
    db_util.insert_into_db(
        job_id, app_instance_id, selected_node_addr, app_run_type	
    )

---

Kill Command

• Deregister app_instance_id to heart beat manager

  • Deregister Process

    deregister_to_heart_beat_manager(app_instance_id) 

    def deregister_to_heart_beat_manager(application_instance_id):
        request_type = 'deregister'
        message = "{} {}-{}".format(
                                request_type, 
                                "application", 
                                application_instance_id
                            )
    
        topic_name = "register_deregister"
        producer.send(topic_name, message.encode())

• Kill Command Send to Node

  msg = "kill_app:" + app_instance_id
  client_sock.send(msg.encode())