Opendaylight analysis of SDN learning (5)

    This section mainly talks about odl Of netconf application , Actually odl More is the use of openflow On the switch downstream table , Realize the real separation of control and forwarding , However, sometimes it doesn't happen . Many actual switches can not achieve real control separation , If you can, then the equipment will make a lot less profits , Therefore, a compromise control scheme for the switch is to use netconf Control the switch ,netconf It can be regarded as a communication protocol , The switch is usually in 830 Port from a server , Accept the request of the client and call , The communication data is xml Format , The client can be python Script , If you want to use odl, It's equivalent to putting odl To the south of plugin As a client , Communicate with the switch .

    Let's first introduce netconf,netconf It's based on XML Network configuration management protocol . Users can use this mechanism to increase 、 modify 、 Delete the configuration of the network device , Get the configuration and status information of network devices .NETCONF Connection oriented , The operation and control are realized by remote procedure call . use XML As the encoding method of configuration data and protocol message content ; Good scalability , Manufacturers can define their own protocol operations , To achieve unique functions ,netconf At the bottom is the establishment of ssh Connect , At the top layer, data interaction is used to obtain configuration , Or modify the machine configuration , Or finish nofication Notification, etc .

         netconf Use simple based on RPC（Remote Procedure Call） Mechanism to realize the communication between client and server . The client can be a script or an application running on the network management . Server is a typical network device .NETCONF A central computer running network management software is provided （ Network management workstation ） To remotely manage and monitor equipment .

       NETCONF The protocol divides data into configuration data and status data , And provide different operations for data addition, deletion, modification and query . The configuration data （configuration data） It is the data for configuring network devices , For example, create VLAN The data of . Configuration data is generally readable and writable . Status data （state data） It is the data reflecting the equipment status , For example, the up/down state , Message statistics, etc . Status data is generally read-only . There will be multiple databases , For example, for running , Or loaded at startup .

              Client and server call rpc There is a process of interaction , First, you need to send hello message, Confirmation ability

        netconf The call operation layer is only hosted in <rpc> and <rpc-reply> On the news ,<hello> and <notification> Message has no operation layer . NETCONF The agreement provides for 9 It's a simple rpc operation , It also supports user-defined rpc operation . Let's put the content of custom actions in the content layer . The open but normative content layer is netconf The essence of the agreement . Its openness is reflected in netconf The protocol itself does not limit the data structure of the content layer . And its specification is reflected in its content layer need to use Yang Language models its data . The content layer does not specify a specific model structure , Instead, it specifies a modeling language –yang. That is to say, use yang Defined data model , Can be used as netconf The content layer of . So the extension is right netconf In other words, it is constantly increasing and modifying yang The file" . In the operation mentioned above netcon User defined operation is supported . In other words, we don't have to worry about standard setting 9 Is each operation type enough , According to the actual needs in yang The corresponding rpc operation .

        Say again odl Inside netconf application development , The first step is to get the of the switch yang file ,yang The file is equivalent to the tree data in the switch , stay odl Inside is under the mount node datastore Save inside , As shown in the figure vlan Of yang Model

 container vlan {
    description
      "VLAN management.";
    container vlans {
      description
        "VLAN list.";
      list vlan {
        key "vlanId";
        max-elements  "4094";
        description
          "VLAN information.";
        leaf vlanId {
          type vlanId {
            range "1..4094";
          }
          description
            "VLAN ID.";
        }
        leaf vlanName {
          type string {
            length "1..31";
          }
          must "not(../vlanType='carrier' or ../vlanType='fcoe')";
          description
            "VLAN name.";
          ext:allowDelete "true";
        }
        leaf vlanDesc {
          type string {
            length "1..80";
          }
          must "not(../vlanType='carrier' or ../vlanType='fcoe')";
          description
            "VLAN description.";
          ext:allowDelete "true";
        }
        leaf vlanType {
          type vlanType;
          must "((../vlanType='common' or ../vlanType='super' or ../vlanType='principal') ) or (../vlanType='common' and (../vlanType='common' or ../vlanType='super' or ../vlanType='principal') ) or (../vlanType='group' and (../vlanType='common' or ../vlanType='group') ) or (../vlanType='principal' and (../vlanType='common' or ../vlanType='principal') ) or (../vlanType='seperate' and (../vlanType='common' or ../vlanType='seperate') ) or (../vlanType='sub' and (../vlanType='common' or ../vlanType='sub') ) or (../vlanType='super' and (../vlanType='common' or ../vlanType='super') ) or not(../vlanType!='common' and ../vlanType!='super' and ../vlanType!='sub' and ../vlanType!='principal' and ../vlanType!='group' and ../vlanType!='seperate' or ../vlanType='common' or ../vlanType='group' or ../vlanType='principal' or ../vlanType='seperate' or ../vlanType='sub' or ../vlanType='super')";
          default "common";
          description
            "VLAN type, such as common VLANs, super VLANs, and sub-VLANs. ";
        }

          utilize yang File by yangtools Generate data nodes java file , Thus, the... Under the equipment node is constructed datasore data , The first is when the equipment is connected , Get mountPoint:

 final Optional<MountPoint> deviceNodeOptional=mountService.getMountPoint(NetconfIidFactory.netconfNodeIid(deviceId));

        deviceId yes connect device Set up device id, And then use it mountPoint Get datastore：

Preconditions.checkArgument(deviceNodeOptional.isPresent(),
                "Unable to locate mountpoint: %s, not mounted yet or not configured", deviceId);
        final MountPoint deviceNode = deviceNodeOptional.get();

        // Get the DataBroker for the mounted node
        final DataBroker deviceNodeBroker = deviceNode.getService(DataBroker.class).get();

          And then the operations datastore The data in it , For example, to get all the information in the switch vlan Configuration of , It's reading datastore Data in node

 final ReadOnlyTransaction deviceNodeReadTx = deviceNodeBroker.newReadOnlyTransaction();
        InstanceIdentifier<Vlans> idn = InstanceIdentifier.create(
                org.opendaylight.yang.gen.v1.http.www.huawei.com.netconf.vrp.huawei.vlan.rev181123.Vlan.class)
               .child(Vlans.class);
        Optional<Vlans> ldn;
        try {
            ldn=deviceNodeReadTx.read(LogicalDatastoreType.OPERATIONAL,idn).checkedGet();
        } catch (ReadFailedException e) {
            throw new IllegalStateException("Unexpected error reading data from " + deviceId, e);
        }

      conversely , To configure vlan Data is written using datastore To achieve ：

 final WriteTransaction deviceNodeWriteTx = deviceNodeBroker.newWriteOnlyTransaction();
        try {
            deviceNodeWriteTx.put(LogicalDatastoreType.CONFIGURATION, idn, data);
            FluentFuture<? extends @NonNull CommitInfo> future = deviceNodeWriteTx.commit();
            future.get(5000, TimeUnit.MILLISECONDS);
        }catch (TimeoutException e){
            return RpcResultBuilder.<ConfigVlanOutput>failed()
                    .withResult(new ConfigVlanOutputBuilder().setResult(e.getMessage())).buildFuture();

        } catch (Exception e) {
            return RpcResultBuilder.<ConfigVlanOutput>failed()
                    .withResult(new ConfigVlanOutputBuilder().setResult(e.getMessage())).buildFuture();
        }

        as for odl Internal implementation principle , It can be understood as the internal setting datastore The monitor for , When data changes , Initiate right mount node Of netconf signal communication , And yes odl netconf You can refer to the following ：

ODL Netconf MountPoint And its cluster mode implementation

https://www.sdnlab.com/22981.html

 

ODL Netconf The underlying connection mechanism is implemented

https://www.sdnlab.com/22997.html

 

Use Docker Container building ODL colony

https://www.sdnlab.com/22554.html

 

ODL Netconf The underlying connection mechanism is implemented

https://www.sdnlab.com/22997.html