NX-SDK

This chapter contains the following sections:

About the NX-SDK

The Cisco NX-OS SDK (NX-SDK) is a C++ abstraction/plugin library layer that streamlines access to infrastructure for automation and custom native application creation, such as generating custom:

  • CLIs.

  • Syslogs.

  • Event and Error managers.

  • Inter-application communication.

  • High availability (HA).

  • Route manager.

The NX-SDK also supports Python bindings.


Note

For Cisco Nexus NX-OS 7.0(3)I6(1) and earlier versions, the NX-SDK is not supported on Cisco Nexus 3000 switches.

Requirements

The NX-SDK has the following requirements:

  • Docker

Install the NX-SDK

Procedure

Step 1

(Optional) Build the Cisco SDK RPM to persist on switch reloads and from standby mode.

Note 

The Cisco SDK is required for applications started in VSH.

The Cisco SDK is optional for applications started in Bash.

  1. Pull the Docker image for Ubuntu 14.04+ or Centos 6.7+ from https://hub.docker.com/r/dockercisco/nxsdk.

  2. Source for a 32-bit environment:

    Example:

    export ENXOS_SDK_ROOT=/enxos-sdk
cd $ENXOS_SDK_Root
source environment-setup-x86-linux
Step 2

Clone the NX-SDK toolkit from https://github.com/CiscoDevNet/NX-SDK.git.

Example:

git clone  https://github.com/CiscoDevNet/NX-SDK.git

What to do next

The following references to the API can be found in $PWD/nxsdk and includes the following:

  • The NX-SDK public C++ classes and APIs,

  • Example applications, and

  • Example Python applications.

Building and Packaging C++ Applications

The following instructions describes how to build and package your custom C++ NX-OS application.

Procedure

Step 1

Build your application files..

  1. Building a C++ application requires adding your source files to the Makefile

    Example:

    The example below uses the customCliApp.cpp file from /examples
    ...
##Directory Structure
...
EXNXSDK_BIN:= customCliApp 
...

  2. Build the C++ application using themake command.

    Example:

    $PWD/nxsdk# make clean
    $PWD/nxsdk# make all
Step 2

(Optional) Package your application.

Auto-generate RPM package

Custom RPM packages for your applications are required to run on VSH and allow you to specify whether a given application persists on switch reloads or system switchovers. Use the following to create a custom specification file for your application.

Note 

RPM packaging is required to be done within the provided ENXOS Docker image.

  1. Use the rpm_gen.py script to auto-generate RPM package for a custom application.

    Example:

    Specify the -h option of the script to display the usages of the script.

    /NX-SDK# python scripts/rpm_gen.py -h

  2. By default, NXSDK_ROOT is set to /NX-SDK. If NX-SDK is installed in another location other than the default, then you must set NXSDK_ROOT env to the appropriate location for the script to run correctly.

    Example:

    export NXSDK_ROOT=<absolute-path-to-NX-SDK>

Example of Auto-generate RPM package for C++ App examples/customCliApp.cpp


/NX-SDK/scripts# python rpm_gen.py CustomCliApp
#########################################################################################################

Generating rpm package... 

Executing(%prep): /bin/sh -e /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/var/tmp/rpm-tmp.49266
+ umask 022 
+ cd /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../src/rpm/BUILD 
+ exit 0 
Executing(%build): /bin/sh -e /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/var/tmp/rpm-tmp.49266
+ umask 022
+ cd /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../src/rpm/BUILD 
+ exit 0 
Executing(%install): /bin/sh -e /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/var/tmp/rpm-tmp.49266
+ umask 022
+ cd /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../src/rpm/BUILD
+ /bin/rm -rf /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../../var/tmp/customCliApp-root 
+ /bin/mkdlr -p /enxos-sdk/sysrOOts/x86_64-wrIinuxsdk-linux/usr/lib/rpm/../../../var/tmp/customCliApp-root//isan/bin 
+ cp -R /NX-SDK/bin /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/.. /../../var/tmp/customCliApp-root//isan/bin 
+ exit 0 
Processing files: customCliApp-1.0-7.03.I6.1.x86_64 
Requires: libc.so.6 libc.so.6(GLIBC 2.0) 3.0) Libc.so.6(GLIBC_2.1.3) libdl.so.2 libgcc_s.so.1 libgcc_s.so.1(GCC_3.0) libm.so.6 libnxsdk.so libstdc++.so.6 libstdc++.so.6 (CXXAB1 1.3) libstdc++.so.6(GLIBCXX 3.4) libstdc++.so.6(GLIBCXX_3.4.14) rt1d(GNU HASH) 
Checking for unpackaged file(s): /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/check-files /enos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../../var/tmp/customCliApp-root 
Wrote: /enxos-sdk/sysrootS/X86_64-wrlinuxsdk-linux/usr/src/rpm/SRPMS/customCliApp-1.0-7.0.3.I6.1.src-rpm 
Wrote: /enxos-sdk/sysrootS/X86_64-wrlinuxsdk-linux/usr/src/rpm/RPMS/x86_64/customCliApp-1.0-7.0.3.I6.1.x86_64.rpm
Executing($clean): /bin/sh -e /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/var/tmp/rpm-tmp.49266 
+ umask 022 
+ cd /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../src/rpm/BUILD
+ / bin/rm -rf /enxos-sdk/sysroots/x86_64-wrlinuxsdk-linux/usr/lib/rpm/../../../var/tmp/customCliApp-root 
RPM package has been built 
#########################################################################################################

SPEC file: /NX-SDK/rpm/SPECS/customCliApp.spec
RPM file : /NX-SDK/rpm/RPMS/customCliApp-1.0-7.0.3.I6.1.x86_64.rpm

Manually-generate RPM Package

Custom RPM packages for your applications are required to run on VSH and allow you to specify whether a given application persists on switch reloads or system switchovers. Use the following steps to create a custom specification file (*.spec) for your application.

  1. Export the Cisco SDK RPM source to $RPM_ROOT.

    Example:

    export RPM_ROOT=$ENXOS_SDK_ROOT/sysroots/x86_64-wrlinuxsdk-linux/usr/src/rpm

  2. Enter the $RPM_ROOT directory.

    Example:

    ls $RPM_ROOT (BUILD RPMS SOURCES SPECS SRPMS)

  3. Create/edit your application-specific *.spec file.

    Refer to the customCliApp.spec file in the /rpm/SPECS directory for an example specification file.

    Note 
    We recommend installing application files to /isan/bin/nxsdk on the switch as per the example customCliApp.spec file.

    Example:

    vi $RPM_ROOT/SPECS/<application>.spec

  4. Build your RPM package.

    Example:

    rpm -ba $RPM_ROOT/SPECS/<application>.spec

    A successful build will generate an RPM file in $RPMS_ROOT/RPMS/x86_64/

Installing and Running Custom Applications

You can install applications by copying binaries to the switch, or installing unpacking the binaries from the RPM package.


Note
Only custom applications that are installed from RPM packages can persist on switch reload or system switchovers. We recommend reserving copying binaries to the switch for simple testing purposes.
To run NX-SDK apps inside the swtich (on box), you must have the Cisco SDK build environment that is installed.

Note

The Cisco SDK is required to start applications in VSH: VSH requires that all applications be installed through RPMs, which requires that being built in the Cisco SDK.

The Cisco SDK is not required for Python application.

The Cisco SDK is not required for C++ application, but is still recommended: Using g++ to build applications and then copying the built files to the switch may pose stability risks as g++ is not supported.

To install or run custom applications on the switch, use this procedure:

Before you begin

The switch must have the NX-SDK enabled before running any custom application. Run feature nxsdk on the switch.

Procedure

Step 1

Install your application using either VSH or Bash.

To install your application using VSH, perform the following:

  1. Add the RPM package to the installer.

    Example:

    switch(config)# install add bootflash:<app-rpm-package>.rpm

  2. After installation, check if the RPM is listed as inactive.

    Example:

    switch(config)# show install inactive

  3. Activate the RPM package.

    Example:

    switch(config)# install activate <app-rpm-package>

  4. After activation, check if the RPM is listed as active.

    Example:

    switch(config)# show install active
To install your application using Bash, run the following commands:
switch(config)# run bash sudo su
bash# yum install /bootflash/<app-rpm-package>.rpm
Step 2

Start your application.

C++ applications can run from VSH or Bash.

  • To run a C++ application in VSH, run the nxsdk command: 

    switch(config)# nxsdk service-name /<install directory>/<application>
    Note 

    If the application is installed in /isan/bin/nxsdk, the full file path is not required. You can use the nxsdk service-name app-name form of the command.

  • To run a C++ application in Bash, start Bash then start the application.

    switch(config)# run bash sudo su
bash# <app-full-path> &

Python applications can run from VSH or Bash.

  • To run a Python application from VSH, run the nxsdk command: 

    switch(config)# nxsdk service-name <app-full-path>
    Note 

    The Python application must be made executable to start from VSH:

    • Run chmod +x app-full-path

    • Add #!/isan/bin/nxpython to the first link of your Python application.

  • To run a Python application from Bash, 

    switch(config)# run bash sudo su
bash# /isan/bin/nxsdk <app-full-path>
    Note 
    By default, NX-SDK uses /isan/bin/nxsdk to run Python applications in Bash, but you can specify a different install directory if needed.
Step 3

Run show nxsdk internal service to verify that your application is running

Example:

switch(config)# show nxsdk internal service

switch(config)# show nxsdk internal service

  NXSDK total services (Max Allowed) : 2 (32)
  NXSDK Default App Path         : /isan/bin/nxsdk
  NXSDK Supported Versions       :  1.0 

  Service-name              Base App        Started(PID)    Version    RPM Package
  ------------------------- --------------- ------------    ---------- --------------------
  /isan/bin/capp1           nxsdk_app2      VSH(25270)      1.0        capp1-1.0-7.0.3.I6.1.x86_64
  /isan/bin/TestApp.py      nxsdk_app3      BASH(27823)     -          -
Step 4

Stop you application.

You can stop your application in the following ways:

  • To stop all NX-SDK applications, run no feature nxsdk .

  • To stop a specific application in VSH, run no nxsdk service-name /install directory/application

  • To stop a specific application in Bash, run application stop-event-loop

Step 5

Uninstall your application.

To uninstall the RPM from the switch using VSH, perform the following:

  1. Deactivate the active RPM package.

    Example:

    switch# install deactive <app-rpm-package>

  2. Verify that the package is deactivated.

    Example:

    switch# show install inactive

  3. Remove the RPM package.

    Example:

    switch# install remove <app-rpm-package>

To uninstall the RPM from the switch using Bash, run yum remove app-full-path