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Northbound gNMI service

The system provides a Northbound gNMI service. gNMI is a specialization of gRPC, specifically for configuration of systems or devices. In onos-config the gNMI interface is secured through TLS, and is made available on port 5150.

gNMI extensions supported on the Northbound are described in gnmi_extensions.md

The impact of the gNMI changes given below can be visualized by running the Configuration Dashboard.

gnmi_cli utility

A simple way to issue a gNMI requests is to use the gnmi_cli utility from the OpenConfig project.

A special version of this tool that can connect over a plain connection is available with go get github.com/onosproject/onos-cli/cmd/gnmi_cli. This version gives the extra -encodingType (-en) and -tlsDisabled (-tls) options.

More instructions including all the examples below can be found in gnmi_cli tool examples.

gnmi_cli utility through onos-cli

On a deployed cluster the onos-cli pod has this gNMI client installed.

You can run the following command to get in to the onos-cli pod and then run gnmi_cli from there:

kubectl -n micro-onos exec -it $(kubectl -n micro-onos get pods -l type=cli -o name) -- /bin/sh

Accessing from local machine

An alternative is to install on your system, install as follows:

go get -u github.com/onosproject/onos-cli/cmd/gnmi_cli

Then you can use k8s port forwarding to run gnmi_cli locally on your machine as follows:

kubectl port-forward -n <onos-namespace> <onos-config-pod-id> 5150:5150

For troubleshooting information see gnmi_user_manual.md

Alternate to gNMI SetRequest in onos-cli

For convenience, another method of calling gNMI SetRequest on onos-config is provided through the onos-cli tool with onos config load yaml. This allows configuration in YAML to be loaded directly in to onos-config

Namespaces

onos-config follows the YGOT project in simplification by not using namespaces in paths. This can be achieved because the YANG models used do not have clashing device names that need to be qualified by namespaces. This helps developers, avoiding un-needed complication and redundancy.

Capabilities

For example use gnmi_cli -capabilities to get the capabilities from the system.

gnmi_cli -capabilities --address=onos-config:5150 \
  -timeout 5s -insecure \
  -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

The Encodings supported are JSON, JSON_IETF, and PROTO.

This returns the aggregate of all of the model plugins and their versions that have been loaded.

Here the certificate locations are inside the onos-cli pod. If the CA does not exactly match the cert inside onos-config and the hostname of the server does not match the cert it is necessary to use the -insecure flag. Encryption is still used in this case.

Northbound Set Request via gNMI

To make a gNMI Set request, use the gnmi_cli -set command as in the example below:

Since the onos-config data store is empty by default, the Set examples are shown before the Get examples (below).

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>> val: <string_val: 'Europe/Paris'>> extension: <registered_ext: <id: 101, msg:'1.0.0'>> extension: <registered_ext: <id: 102, msg:'Devicesim'>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

giving a response like

response: <
  path: <
    elem: <
      name: "system"
    >
    elem: <
      name: "clock"
    >
    elem: <
      name: "config"
    >
    elem: <
      name: "timezone-name"
    >
    target: "devicesim-1"
  >
  op: UPDATE
>
timestamp: 1559122191
extension: <
  registered_ext: <
    id: 100
    msg: "c21a1aa5-76d6-11eb-81af-6f6e6f732d63"
  >
>

The result will include a field as a gNMI SetResponse extension 100 giving randomly generated Network Change identifier, which may be subsequently used to rollback the change.

If a specific name is desired for a Network Change, the set may be given in the SetRequest() with the 100 extension at the end of the -proto section like: , extension: <registered_ext: <id: 100, msg: 'myfirstchange'>> See gnmi_extensions.md for more on gNMI extensions supported.

If a name is given a 2nd time, it wil produce an error rpc error: code = Internal desc = write condition failed

Checking of the contents is done only when a Model Plugin is loaded for the device type. 2 checks are done

  1. that a attempt is not being made to change a readonly attribute and
  2. that valid data types and values are being used.

The config is only forwarded down to the southbound layer only if the config is correct and the device is currently in the deviceStore.

Set on multiple targets in one request.

onos-config gNMI NB supports setting multiple elements on multiple targets at the same time.
An example of an attribute on two targets is:

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'devicesim-1', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'config'> elem: <name: 'name'>> val: <string_val: 'eth1'>> extension: <registered_ext: <id: 100, msg:'added_devicesim-1-IF'>> update: <path: <target: 'devicesim-2', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'config'> elem: <name: 'name'>> val: <string_val: 'eth1'>> extension: <registered_ext: <id: 101, msg:'1.0.0'>> extension: <registered_ext: <id: 102, msg:'Devicesim'>>" \
    -timeout 5s -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt \
    -client_key /etc/ssl/certs/client1.key \
    -ca_crt /etc/ssl/certs/onfca.crt

An example of setting two attributes on two targets:

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'devicesim-1', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'hold-time'> elem: <name: 'config'> elem: <name: 'up'>> val: <uint_val: 123456>> update: <path: <target: 'devicesim-1', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'hold-time'> elem: <name: 'config'> elem: <name: 'down'>> val: <uint_val: 54321>> update: <path: <target: 'devicesim-2', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'hold-time'> elem: <name: 'config'> elem: <name: 'up'>> val: <uint_val: 765432>> update: <path: <target: 'devicesim-2', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1' >> elem: <name: 'hold-time'> elem: <name: 'config'> elem: <name: 'down'>> val: <uint_val: 234567>> extension: <registered_ext: <id: 100, msg:'add_hold_times'>>" \
    -timeout 5s -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt \
    -client_key /etc/ssl/certs/client1.key \
    -ca_crt /etc/ssl/certs/onfca.crt

Adding an "eth2" to each of the devices

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'devicesim-1', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth2' >> elem: <name: 'config'> elem: <name: 'name'>> val: <string_val: 'eth2'>> extension: <registered_ext: <id: 100, msg:'added_devicesim-1-IF2'>> update: <path: <target: 'devicesim-2', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth2' >> elem: <name: 'config'> elem: <name: 'name'>> val: <string_val: 'eth2'>> extension: <registered_ext: <id: 100, msg:'2nd_devicesimIF2'>> extension: <registered_ext: <id: 101, msg:'1.0.0'>> extension: <registered_ext: <id: 102, msg:'Devicesim'>>" \
    -timeout 5s -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt \
    -client_key /etc/ssl/certs/client1.key \
    -ca_crt /etc/ssl/certs/onfca.crt

There is a quirk with the OpenConfig models (e.g. for Stratum and Devicesim), where the name of the interface is a leaf ref to a name attribute beneath it. This means that an interface cannot be created without specifying the config/name attribute at the same time (as above). Otherwise error rpc error: code = InvalidArgument desc = pointed-to value with path ../config/name from field Name value eth2 (string ptr) schema /device/interfaces/interface/name is empty set will occur.

Adding attributes to existing interface

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'devicesim-1', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name'value:'eth1'>> elem: <name: 'config'> elem: <name: 'enabled'>> val: <bool_val: true>> update: <path: <target: 'devicesim-1',elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth2'>> elem: <name: 'config'> elem: <name: 'enabled'>> val: <bool_val: true>> update: <path: <target: 'devicesim-2', elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth1'>> elem: <name: 'config'> elem: <name: 'enabled'>> val: <bool_val: true>> update: <path: <target: 'devicesim-2',elem: <name: 'interfaces'> elem: <name: 'interface' key:<key:'name' value:'eth2'>> elem: <name: 'config'> elem: <name: 'enabled'>> val: <bool_val: true>> extension: <registered_ext: <id: 100,msg:'add_enabled'>>" \
    -timeout 5s -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt \
    -client_key /etc/ssl/certs/client1.key \
    -ca_crt /etc/ssl/certs/onfca.crt

Target device not known/creating a new device target

If the target device is not currently known to onos-config the system will store the configuration internally and apply it to the target device when/if it becomes available.

When the target becomes available onos-config will compute the latest configuration for it based on the set of applied changes and push it to the target with a standard set operation.

In the case where the target device is not known, a special feature of onos-config has to be invoked to tell the system the type and version to use as a model plugin for validation - these are given in extensions 101 (version) and 102 (type).

This can be used to pre-provision new devices or new versions of devices before they are available in the onos-topo topology.

For example using the gnmi_cli:

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "update: <path: <target: 'new-device', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>> val: <string_val: 'Europe/Paris'>>, extension: <registered_ext: <id: 100, msg: 'my2ndchange'>>  , extension <registered_ext: <id: 101, msg: '1.0.0'>>, extension: <registered_ext: <id: 102, msg: 'Devicesim'>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

There are restrictions on the use of these extensions in this context: * All targets specified in this set command will have to be of the same type and version as given in extension 101 and 102, even if they already exist on the system.

After creating all of these the dashboard will show each Set operation as a row, and each device as a column. Dashboard

Drilling down specifically in to "devicesim-1", we can see the layers of configuration: devicesim-1

Northbound gNMI Get Request

onos-config extends standard gNMI as a method of accessing a complete configuration system consisting of several devices - each identified by target. It supports network wide configuration actions (multiple updates on multiple devices at once, and rollback of same).

The gNMI Northbound interface is available through https on port 5150.

As described in Key Concepts, even if the device-simulator is connected the configuration in onos-config will be empty as no initial synchronization is done. A Set operation is necessary before a Get will show any results.

A simple Get operation

Use gnmi_cli -get to get configuration for a particular device (target) from the system.

Use "target" as the identifier of the device, and the "elem" collection is the path to the requested element. If config from several devices are required, several paths can be added

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

List all device names (targets)

A useful way to retrieve all stored device names is with the command:

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path: <target: '*'>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

Here the encoding requested was PROTO which will returnt the values in a Lef List. Alternatively JSON could have been used, which will give a JSON payload in a JSON_Val.

List complete configuration for a device (target)

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path: <target: 'devicesim-1'>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

Here all elem components are omitted, which is like requesting '/'. The result will be returned as a JSON value.

Get a keyed index in a list

Use a proto value like:

gnmi

-proto "path: <target: 'devicesim-1',
         elem: <name: 'system'>
         elem: <name: 'openflow'> elem: <name: 'controllers'>
         elem: <name: 'controller' key: <key: 'name' value: 'main'>>
         elem: <name: 'connections'> elem: <name: 'connection' key: <key: 'aux-id' value: '0'>>
         elem: <name: 'config'> elem: <name: 'address'>>"

Use wildcards in a path

onos-config supports the wildcards * and ... in gNMI paths, meaning match one item of match all items respectively as defined in the gNMI specification.

For instance to retrieve all instances of an interface use * as the key:

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path:<target: 'devicesim-1', elem:<name:'interfaces' > elem:<name:'interface' key:<key:'name' value:'*' > > elem:<name:'config'> elem:<name:'enabled' >>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

This returns the enabled config attribute of both interfaces 'eth1' and 'admin'

To retrieve both the config and state values of both then additionally the use * in place of config:

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path:<target: 'devicesim-1', elem:<name:'interfaces' > elem:<name:'interface' key:<key:'name' value:'*' > > elem:<name:'*'> elem:<name:'enabled' >>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

If the device is connected and the OperationState cache is populated this returns 4 values - eth1 config and state enabled values and admin config and state enabled values.

Device read only state get

To retrieve state attributes (those defined in YANG with config false, non-configurable leafs), in general there is no difference with a normal gNMI Get request.

There is however a type qualifier STATE in gNMI Get, that allows only STATE values to be requested (excluding any CONFIG attributes. For example to retrieve all the STATE values from devicesim-1:

gnmi

gnmi_cli -get -address onos-config:5150 \
    -proto "path: <target: 'devicesim-1'>, type: STATE" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

The set of possible values for type are: ALL, STATE, CONFIG and OPERATIONAL. If not specified ALL is the default type. In onos-config there is no distinction made between STATE and OPERATIONAL and requesting either will get both. This type can be combined with any other proto qualifier like elem and prefix

Northbound Delete Request via gNMI

A delete request in gNMI is done using the set request with delete paths instead of update or replace. To make a gNMI Set request do delete a path, use the gnmi_cli -set command as in the example below:

gnmi

gnmi_cli -address onos-config:5150 -set \
    -proto "delete: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

Northbound Subscribe Request for Stream Notifications via gNMI

Similarly, to make a gNMI Subscribe request for streaming, use the gnmi_cli command as in the example below, please note the 0 as subscription mode to indicate streaming:

gnmi

gnmi_cli -address onos-config:5150 \
    -proto "subscribe:<mode: 0, prefix:<>, subscription:<path: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>>>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

This command will block until there is a change at the requested value that gets propagated to the underlying stream. Also as per gnmi_cli behaviour the updates get printed twice.

Northbound Subscribe Once Request via gNMI

Similarly, to make a gNMI Subscribe Once request, use the gnmi_cli command as in the example below, please note the 1 as subscription mode to indicate to send the response once:

gnmi

gnmi_cli -address onos-config:5150 \
    -proto "subscribe:<mode: 1, prefix:<>, subscription:<path: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>>>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

This command will fail if no value is set at that specific path. This is due to limitations of the gnmi_cli.

Northbound Subscribe Poll Request via gNMI

Similarly, to make a gNMI Subscribe POLL request, use the gnmi_cli command as in the example below, please note the 2 as subscription mode to indicate to send the response in a polling way every polling_interval specified seconds:

gnmi

gnmi_cli -address onos-config:5150 -polling_interval 5s \
    -proto "subscribe:<mode: 2, prefix:<>, subscription:<sample_interval: 5, path: <target: 'devicesim-1', elem: <name: 'system'> elem: <name: 'clock' > elem: <name: 'config'> elem: <name: 'timezone-name'>>>>" \
    -timeout 5s -en PROTO -alsologtostderr -insecure \
    -client_crt /etc/ssl/certs/client1.crt -client_key /etc/ssl/certs/client1.key -ca_crt /etc/ssl/certs/onfca.crt

This command will fail if no value is set at that specific path. This is due to limitations of the gnmi_cli.