AlteonOS has a
reach REST API
for monitor,
operation, and configuration.
REST can
be used/
called with
verity of programming
languages,
or even just using wget.
However, since
this blog
was already using TCL
for AppShape++ scripting,
we may as
well keep using TCL
for REST too.
However, RESTing with
TCL is a
bit pain in
the ...,
so this time I'll
use python instead.
All most forgot to
explain what REST is.
Its a
way to
run remote procedures calls using HTTP.
Example calls:
- Read interface counters
- Update real's weight
- Bring down a real inside a group
I strongly recommend using a browser plugin for testing out REST calls. I use
HttpRequest for firefox.
Here are two
screenshots.
The first is
how I
get the current status of
real 1
, and the second is
how I
disable real 1.
Lab goal
Using the base setup, create python script to toggle the status of real 1 from not enabled to enabled and from disable to enable.
Setup
The loadbalancer is Radware's Alteon VA version 29.5.1.0
The initial Alteon VA configuration can be found
here.
Notice the group and hosts are preconfigured:
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| /c/slb/real 1
ena
ipver v4
rip 10.136.85.1
/c/slb/real 2
ena
ipver v4
rip 10.136.85.2
/c/slb/real 3
ena
ipver v4
rip 10.136.85.3
/c/slb/group 10
ipver v4
add 1
add 2
add 3
|
Python script
I have used python 2.7 and the following modules:
json and
requests
Alteon's REST API is using json as its data format. Python's build in json module converts
python dict to
json format and vice-versa.
requests is a very easy python module to use for REST API.
Here is the source code for the python script. See the comments inside for explanations:
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| import requests
import json
import sys
# set Alteon and real parameters
ALTEON = "10.136.1.100"
REAL = "1"
USER = "admin"
PASSWORD = "admin"
# get the current status of real server
# ============================================================
# set authentication object
myAuth=requests.auth.HTTPBasicAuth(USER, PASSWORD)
# set request string with the ALTEON name/ip address and the 'real' we want to toggle
reqSTR = "https://"+ALTEON+"/config/SlbOperEnhRealServerTable/" + REAL
# turn off SSL warning. Don't do this in production!
# see here how to deal with it http://docs.python-requests.org/en/latest/user/advanced/#ssl-cert-verification
requests.packages.urllib3.disable_warnings()
# send the request, use the auth object, don't verify certification and return a python dct out of json string
# The return is a one item dict with 'SlbNewCfgEnhRealServerTable' as key.
# That item contains one item list, hence the [0]
# That list item is another dict with two entries: 'Status' and 'Index' we need the Status
r = requests.get(reqSTR, auth=myAuth, verify=False).json()['SlbOperEnhRealServerTable'][0]
state = r['Status']
# print current state and set the new requierd state
if state == 1:
print "Real is enabled. Changing status to disabled"
newStatus = "2" # disabled
elif state == 2:
print "Real is disabled. Changing status to enabled"
newStatus = "1" # enabled
elif state == 3:
print "Real is disabled but waiting for cookies to timeout. Changing status to enabled"
newStatus = "1" # enabled
elif state == 4:
print "Real is disabled but waiting for sessions to timeout. Changing status to enabled"
newStatus = "1" # enabled
elif state == 5:
print "Real is disabled but waiting for sessions to timeout and for cookeis to timeout. Changing status to enabled"
newStatus = "1" # enabled
else:
# we should never get here
print "error retrieving real status. return object:"
print r
sys.exit(0)
# set the new real status
# ============================================================
# create JSON data to be passed
myData = json.dumps({'Status' : newStatus})
# send the oper command to change the status. Notice that his time the method is PUT
r = requests.put(reqSTR, auth=myAuth, verify=False, data=myData).json()['status']
# print the return status of the command
print r
|
Test
Notice how the status is changing from one run to the other.
Summary
Alteon's REST API is easy to use and straight forward. It is way better then using
expect scripts for automation.
