Cisco Nexus 5000 and 6000 Series NX-OS Programmability Guide
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- Updated:
- January 25, 2018
Chapter: Python API
Python API
- Information About the Python API
- Installing Python
- Using Python
- Application Programming Interface (API) Functions
Information About the Python API
Python is an easy to learn, powerful programming language. It has efficient high-level data structures and a simple but effective approach to object-oriented programming. Python’s elegant syntax and dynamic typing, together with its interpreted nature, make it an ideal language for scripting and rapid application development in many areas on most platforms.
The Python interpreter and the extensive standard library are freely available in source or binary form for all major platforms from the Python website:
The same site also contains distributions of and pointers to many free third-party Python modules, programs and tools, and additional documentation.
 Note | You can know the latest development on Cisco Nexus 5000 Series switches and contribute your ideas by joining the community code sharing page: https://github.com/datacenter |
The Cisco Nexus 5000 series switches with Releases 5.2(1)N1(1) and later and the Cisco Nexus 6000 series switches with Releases 6.0(2)N1(1)and later, support all the features available in Python v2.7.2.
The Python scripting capability on Cisco Nexus 5000 and Cisco Nexus 6000 series switches enables you to perform the following tasks:
- Run a script to verify configuration on switch bootup.
- Back up a configuration.
- Proactive congestion management by monitoring and responding to buffer utilization characteristics.
- Integration with the Power-On Auto Provisioning or EEM modules.
- Ability to perform a job at a specific time interval (such as Port Auto Description).
- Programmatic access to the switch command line interface (CLI) to perform various tasks.
Installing Python
The Python interpreter is available by default on the Cisco NX-OS software.You can invoke Python by entering the python command, and write scripts to access Cisco NX-OS APIs by importing the cisco.py module using the import cisco command.
Installing Third Party Pure Python Packages
You can install the third party pure Python package by copying mypkg.tgz on your server. Perform the following steps to extract and install the third party package:
- Secure copy the tar file by executing the copy scp://user@server/path/to/mypkg.tgz bootflash:mypkg.tgz vrf management command
- Untar the mypkg.tgz file by using the tar extract bootflash:mypkg.tgz command.
- Move the extracted file to bootflash by using the move bootflash:mypkg-1.2/* bootflash: command.
- You can install the package by using the python setup.py install command.
- Remove the copied file from bootflash.
- You can use the third party package in scripts or in the Python shell.
switch# python >>> import mypkg
Note | You will be able to install the third party packages using the easy_install command, in the future releases. |
Using Python
This section describes how to write and execute Python scripts by passing parameters and includes the following topics:
Entering Python Shell
You can enter the Python shell by using the python command without any parameters.
switch# python Python 2.7.2 (default, Oct 11 2011, 13:55:49) [GCC 3.4.3 (MontaVista 3.4.3-25.0.143.0800417 2008-02-22)] on linux2 Type "help", "copyright", "credits" or "license" for more information. Loaded cisco NX-OS lib! >>> print 'helo world!' helo world! >>>exit() switch#
Executing Scripts
For NX-OS releases earlier than 7.0N, you can execute a Python script by using the python <filename> command.
switch# python test.py ['/bootflash/test.py'] doing 0/1 doing 0/2 doing 1/2 switch#
For NX-OS releases 7.0N and later, you can execute a Python script by using the source <filename> command.
switch# source test.py ['/bootflash/test.py'] doing 0/1 doing 0/2 doing 1/2 switch#
Passing Parameters to the Script
For NX-OS releases earlier than 7.0N, you can pass parameters to a Python script by using the python <filename> [arg1, arg2, arg3,.....] command.
switch# python test.py foo bar 1 2 ['/bootflash/test.py', 'foo', 'bar', '1', '2'] doing 0/1 doing 0/2 doing 1/2 switch#
For NX-OS releases 7.0N and later, you can pass parameters to a Python script by using the source <filename> [arg1, arg2, arg3,.....] command.
switch# source test.py foo bar 1 2 ['/bootflash/test.py', 'foo', 'bar', '1', '2'] doing 0/1 doing 0/2 doing 1/2 switch#
Application Programming Interface (API) Functions
This chapter provides information about the following Python Application Programming Interface (API) functions. This chapter includes the following sections:
- Routes()
- show_arp_table()
- show_vsh_routes()
- show_hw_routes()
- verify_routes()
- verify_arp_table()
- CheckPortDiscards()
- transfer()
- CLI()
- get_output()
- rerun()
- History()
- get_history()
- clear_history()
Routes()
Synopsis
Routes() - Class Object
Syntax
Routes()
Description
Instantiates an object of the Routes class.
Parameters
None.
Returns
An object of Routes class.
Example
rObj = Routes()
show_arp_table()
Synopsis
show_arp_table()
Syntax
Routes.show_arp_table()
Description
Executes the show ip arp command and returns the output.
Parameters
None.
Returns
Returns the ARP table entries on the switch.
Example
routeObj = Routes() data = routeObj.show_arp_table().get_output()
Sample Output
Flags: D - Static Adjacencies attached to down interface IP ARP Table for context default Total number of entries: 4 Address Age MAC Address Interface 50.1.201.2 00:02:10 547f.ee40.5a7c Vlan201 50.1.1.10 00:07:53 547f.ee62.f801 Ethernet1/34 50.1.2.10 00:08:31 547f.ee62.f801 Ethernet1/35 50.1.3.10 00:08:31 547f.ee62.f801 Ethernet1/35.1 <cisco.CLI object at 0xb7c1462c>
show_vsh_routes()
Synopsis
show_vsh_routes()
Syntax
Routes.show_vsh_routes()
Description
Executes the show ip fib route and returns the output.
Parameters
None.
Returns
Returns the software route entries.
Example
routeObj = Routes() data = routeObj.show_vsh_routes().get_output()
Sample Output
IPv4 routes for table default/base ------------------+------------------+--------------------- Prefix | Next-hop | Interface ------------------+------------------+--------------------- 0.0.0.0/32 Drop Null0 50.1.1.0/24 Attached Ethernet1/34 50.1.1.0/32 Drop Null0 50.1.1.10/32 50.1.1.10 Ethernet1/34 50.1.1.100/32 Receive sup-eth1 50.1.1.255/32 Attached Ethernet1/34 50.1.2.0/24 Attached Ethernet1/35 50.1.2.0/32 Drop Null0 50.1.2.10/32 50.1.2.10 Ethernet1/35 50.1.2.100/32 Receive sup-eth1 50.1.2.255/32 Attached Ethernet1/35 50.1.3.0/24 Attached Ethernet1/35.1 50.1.3.0/32 Drop Null0 50.1.3.10/32 50.1.3.10 Ethernet1/35.1 50.1.3.100/32 Receive sup-eth1 50.1.3.255/32 Attached Ethernet1/35.1 <cisco.CLI object at 0xb7b0a6ac>
show_hw_routes()
Synopsis
show_hw_routes()
Syntax
Routes.show_hw_routes()
Description
Computes the hardware routes and returns the output.
Parameters
None.
Returns
Returns the hardware route entries.
Example
routeObj = Routes() data = routeObj.show_hw_routes()
Sample Output
------------------+------------------+--------------------- Prefix | Next-hop | Interface ------------------+------------------+--------------------- 50.1.1.100/32 Receive sup-eth1 50.1.2.100/32 Receive sup-eth1 50.1.201.1/32 Receive sup-eth1 0.0.0.0/32 Drop Null0 50.1.3.0/32 Drop Null0 50.1.201.0/32 Drop Null0 50.1.2.255/32 Attached sup-hi 50.1.1.255/32 Attached sup-hi 60.1.1.0/32 Drop Null0 50.1.3.255/32 Attached sup-hi 50.1.201.255/32 Attached sup-hi 255.255.255.255/32 Receive sup-eth1
verify_routes()
Synopsis
verify_routes()
Syntax
Routes.verify_routes()
Description
Verifies the software and hardware routes.
Parameters
None.
Returns
Returns the number of routes matched and unmatched between hardware and software.
Example
routeObj = Routes() found,nfound = routeObj.verify_routes()
Sample Output
Routes verified and found: 26 Routes not found: 50.1.205.0/24 3 51.1.1.0/24 3 51.1.2.0/24 4 51.1.3.0/24 6 100.1.1.0/24 7 100.1.2.0/24 7 100.1.3.0/24 7 101.1.1.0/24 7 101.1.2.0/24 7 101.1.3.0/24 7 120.1.1.0/24 7
verify_arp_table()
Synopsis
verify_arp_table()
Syntax
Routes.verify_arp_table()
Description
Verifies the software and hardware ARP table entries.
Parameters
None.
Returns
Returns the number of ARP table entries matched and unmatched between hardware and software.
Example
routeObj = Routes() found,notfound = routeObj.verify_arp_table()
Sample Output
Flags: D - Static Adjacencies attached to down interface IP ARP Table for context default Total number of entries: 4 Address Age MAC Address Interface 50.1.201.2 00:02:31 547f.ee40.5a7c Vlan201 50.1.1.10 00:08:15 547f.ee62.f801 Ethernet1/34 50.1.2.10 00:08:53 547f.ee62.f801 Ethernet1/35 50.1.3.10 00:08:53 547f.ee62.f801 Ethernet1/35.1 mac address:54:7f:ee:40:5a:7c Arp entry for 50.1.201.2 547f.ee40.5a7c Vlan201 found in HW mac address:54:7f:ee:62:f8:01 Arp entry for 50.1.1.10 547f.ee62.f801 Ethernet1/34 found in HW mac address:54:7f:ee:62:f8:01 Arp entry for 50.1.2.10 547f.ee62.f801 Ethernet1/35 found in HW mac address:54:7f:ee:62:f8:01 Arp entry for 50.1.3.10 547f.ee62.f801 Ethernet1/35.1 found in HW
CheckPortDiscards()
Synopsis
CheckPortDiscards(<port>)
Syntax
CheckPortDiscards('ethernet1/1')
Description
Check the input discards for given port. If discard is more than 0, query and print the discard reason from broadcom.
Parameters
port
Returns
None.
Example
c = CheckPortDiscards('eth1/1')
Sample Output
Ethernet1/1 is up
Hardware: 100/1000/10000 Ethernet, address: 547f.ee57.dd28 (bia 547f.ee57.dd28)
MTU 1500 bytes, BW 10000000 Kbit, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA
Port mode is trunk
full-duplex, 10 Gb/s, media type is 10G
Beacon is turned off
Input flow-control is off, output flow-control is off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
Last link flapped 00:42:16
Last clearing of "show interface" counters never
30 seconds input rate 5016 bits/sec, 627 bytes/sec, 6 packets/sec
30 seconds output rate 3232 bits/sec, 404 bytes/sec, 5 packets/sec
Load-Interval #2: 5 minute (300 seconds)
input rate 4.69 Kbps, 7 pps; output rate 2.82 Kbps, 4 pps
RX
297 unicast packets 20588 multicast packets 5 broadcast packets
20890 input packets 1848701 bytes
0 jumbo packets 0 storm suppression packets
0 giants 0 input error 0 short frame 0 overrun 0 underrun
0 watchdog 0 if down drop
0 input with dribble 0 input discard(includes ACL drops)
0 Rx pause
TX
262 unicast packets 16151 multicast packets 5 broadcast packets
16418 output packets 1407200 bytes
0 jumbo packets
0 output errors 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble
0 Tx pause
2 interface resets
zero discards
transfer()
Synopsis
transfer()
Syntax
transfer (<protocol>, <host>, <source>, <dest>, <vrf>, <login_timeout>, <user>, <password>)
Description
API to transfer file specified in <source> from <host> to the path mentioned in <dest> using <protocol>. Protocol can be scp, tftp, ftp or sftp.
Parameters
protocol, host, source, dest, vrf, login_timeout, user, password.
Returns
Returns True if transfer was successful.
Example
Transfer using scp:
c = transfer("scp", "10.193.190.100", "/tftpboot/transfer_test_image", "transfer_test_image", user="scpUser", password="scpPasswd")
Transfer using sftp:
c = transfer("sftp", "10.193.190.100", "/tftpboot/transfer_test_image", "transfer_test_image", user="sftpUser", password="sftpPasswd")
Transfer using tftp:
c = transfer("tftp", "10.193.190.100", "/transfer_test_image", "transfer_test_image", user="", password="")
Transfer using ftp:
c = transfer("ftp", "10.193.190.51", "golden/home/su-ash/transfer_test_image", "transfer_test_image", user="ftpUser", password="ftpPasswd")
CLI()
Synopsis
CLI() - Class Object
Syntax
CLI (<command>, <do_print>)
Description
Instantiates an object of the CLI class with the CLI command specified in <command>. <do_print> when set to False does not print the output of the command and prints the output when set to True, which is the default.
Note | The CLI command name is case sensitive (uppercase). |
Parameters
command, do_print
Returns
An object of CLI class.
Example
c = CLI ('show runn inter eth1/1')
Sample Output
!Command: show running-config interface Ethernet1/1 !Time: Mon Feb 27 14:33:24 2012 version 5.0(3)U3(1) interface Ethernet1/1 switchport mode trunk udld enable channel-group 12 <cisco.CLI object at 0xb7ae948c>
get_output()
Synopsis
get_output()
Syntax
CLI.get_output()
Description
Returns the output of the CLI command.
Parameters
None.
Returns
Output of the CLI command.
Example
c = CLI ('show runn inter eth1/1')
c.get_output()
Sample Output
['', '!Command: show running-config interface Ethernet1/1', '!Time: Mon Feb 27 14:36:10 2012', '', 'version 5.0(3)U3(1)', '', 'interface Ethernet1/1', ' switchport mode trunk', ' udld enable', ' channel-group 12', '', '']
rerun()
Synopsis
rerun()
Syntax
CLI.rerun()
Description
Reruns the command.
Parameters
None.
Returns
None.
Example
c = CLI ('show runn inter eth1/1')
c.rerun()
Sample Output
!Command: show running-config interface Ethernet1/1 !Time: Mon Feb 27 14:37:05 2012 version 5.0(3)U3(1) interface Ethernet1/1 switchport mode trunk udld enable channel-group 12
History()
Synopsis
History() - Class Object
Syntax
History()
Description
Instantiates an object of the History class.
Parameters
None.
Returns
An object of History class.
Example
a = History()
get_history()
Synopsis
get_history()
Syntax
History.get_history()
Description
Gets the history of CLI commands executed so far.
Parameters
None.
Returns
Returns the history of commands executed.
Example
a = History() a.get_history()
clear_history()
Synopsis
clear_history()
Syntax
History.clear_history()
Description
Clears history.
Parameters
None.
Returns
None.
Example
a = History() a.clear_history()
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