Providing services for logical networks

Abstract

Some embodiments provide a method for a network controller that manages several logical networks. The method receives a specification of a logical network that includes at least one logical forwarding element attached to a logical service (e.g., DHCP). The method selects at least one host machine to host the specified logical service from several host machines designated for hosting logical services. The method generates logical service configuration information for distribution to the selected host machine. In some embodiments, the method selects a master host machine and a backup host machine for hosting logical service. In some embodiments, a particular one of the designated host machines hosts at least two DHCP services for two different logical networks as separate processes operating on the particular host machine.

1 - 24 . (canceled) 
     
     
         25 . A machine readable medium storing a program which when executed by at least one processing unit of a host computer converts a Dynamic Host Configuration Protocol (DHCP) configuration into a configuration file for a particular DHCP application executing on the host computer, the program comprising sets of instructions for:
 receiving the DHCP configuration, wherein the configuration specifies at least one DHCP option to be declared in the configuration file along with a value for the option;   when the particular DHCP application supports the specified option, writing the specified option and the value for the option into the configuration file; and   when the particular DHCP application does not support the specified option, writing a set of supported DHCP options and corresponding values into the configuration file that are functionally equivalent to the specified option and the value for the option.   
     
     
         26 . The machine readable medium of  claim 25 , wherein the program is an application that executes in virtualization software of the host computer. 
     
     
         27 . The machine readable medium of  claim 25 , wherein the program comprises pre-specified instructions for converting each unsupported DHCP option. 
     
     
         28 . The machine readable medium of  claim 25 , wherein the set of instructions for writing the functionally equivalent set of supported DHCP options and corresponding values comprises sets of instructions for:
 defining a new option in the DHCP configuration file; and   writing the newly defined option with a set of values that specifies to the particular DHCP application how to insert the specified option into a DHCP packet.   
     
     
         29 . A non-transitory machine readable medium storing a program for execution by at least one processing unit of a host computer, the program comprising sets of instructions for:
 receiving a modification to a database table used to generate a configuration file for a Dynamic Host Configuration Protocol (DHCP) application that executes on the host computer to provide DHCP service to one or more logical forwarding elements of a logical network according to the configuration file;   determining whether the modification to the database table requires restarting the DHCP application;   when the modification to the database table requires restarting the DHCP application, modifying the configuration file based on the modification to the database table and sending a command to the DHCP application to restart; and   when the modification to the database table does not require restarting the DHCP application, directly accessing the DHCP application during operation to modify the configuration file based on the modification to the database table.   
     
     
         30 . The non-transitory machine readable medium of  claim 29 , wherein the set of instructions for receiving the modification comprises a set of instructions for receiving a change in a set of database table entries that define the DHCP application configuration. 
     
     
         31 . The non-transitory machine readable medium of  claim 29 , wherein the modification does not require restarting the DHCP application when the modification adds or removes a virtual machine from a list of virtual machines that receive the DHCP service. 
     
     
         32 . The non-transitory machine readable medium of  claim 29 , wherein the modification requires restarting the DHCP application when the modification to the database table (i) adds or removes a logical switch from a list of subnets that receive the DHCP service or (ii) modifies a set of global options for all virtual machines that receive the DHCP service. 
     
     
         33 . The non-transitory machine readable medium of  claim 29 , wherein the program further comprises a set of instructions for modifying the configuration file for the DHCP application to reflect the modification to the database table without sending a command to the DHCP application when the modification to the database table does not require restarting the DHCP module. 
     
     
         34 . A host computer for providing Dynamic Host Configuration Protocol (DHCP) services for a set of logical networks, the host computer comprising:
 a set of processing units; and   a non-transitory machine readable medium storing:
 one or more containers for execution by the set of processing units, each respective container executing a respective DHCP application that provides DHCP service to a respective logical network of the set of logical networks; 
 a set of database tables for storing configuration data for the containers and the DHCP applications; and 
 an application for execution by the set of processing units, the application for (i) monitoring the set of database tables for changes that affect the containers and DHCP applications and (ii) converting the set of database tables into configuration files for the DHCP applications, wherein each respective DHCP application uses a respective configuration file to provide DHCP service to the respective logical network. 
   
     
     
         35 . The host computer of  claim 34 , wherein a particular container executes both (i) its respective DHCP application for providing DHCP service to its respective logical network and (ii) an additional application for providing a different service other than DHCP service to its respective logical network. 
     
     
         36 . The host computer of  claim 34 , wherein the non-transitory machine readable medium stores at least one additional container, for execution by the set of processing units, in which a DHCP application does not execute. 
     
     
         37 . The host computer of  claim 34 , wherein the non-transitory machine readable medium further stores a managed forwarding element which when executed by the set of processing units implements a set of logical forwarding elements of the set of logical networks, each respective logical forwarding element of at least a subset of the logical forwarding elements logically attaching to the respective container executing the respective DHCP application providing DHCP service for the respective logical network to which the respective logical forwarding element belongs. 
     
     
         38 . The host computer of  claim 34 , wherein the application executes in virtualization software of the host computer and comprises:
 a monitor for monitoring the database tables;   a first configuration generator for converting the set of database tables into the configuration files for the DHCP applications; and   a second configuration generator for performing runtime modification on the DHCP applications.