open source

DevOps with physical servers using Redfish Python api

Christopher Simpson

Mar 16, 2023 • 5 min read

Using the Redfish api to manage physical server(s) via the Python api to automate server provisonning. (in the spirit of cattle not pets).

Using the Redfish ('standard') REST api, you can command and control iDRAC enabled servers just like you would your software. Software continues to eat the world, and is coming for your hardware.

Why do we not treat our physical servers as part of our DevOps / operations processes? I think it's largely because we think its more expensive, more costly, and more complex than it is.
Today, the reality is quite different.

Code for the above:

The humble server(s)

768GB of RAM, 22-Core 44-Threads X 2 (44 total cores, 88 threads) for £66 a month. That's not a typo.

Enter DMTF Redfish - can I treat my boxes as cattle too?

DMTF’s Redfish® is a standard designed to deliver simple and secure management for converged, hybrid IT and the Software Defined Data Center (SDDC). Both human readable and machine capable, Redfish leverages common Internet and web services standards to expose information directly to the modern tool chain. Redfish

When you read Dells implementation of iDRAC-Redfish-Scripting you quickly see the opportunity to build and improve on.

Here's an example, via an REST api call, get the PowerState of your physical server (is it on or off- remember iDRAC is a form of ' Out of band management', meaning you can connect to your hardware even if the server isn't booted).

python GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --get

- INFO, Current server power state: On

- Supported values to set server power state:

On
ForceOff
ForceRestart
GracefulShutdown
PushPowerButton
Nmi

Getting the power state of the server via the Redfish API using iDRAC-Redfish-Scripting

Today we expect a developer experience to include:

A 'getting starting' / how to install on the first page
JSON has won, we expect at least to be able to get an application/json response

For some reason the request takes over 8 seconds to complete, despite being on the same network at the physical server:

time python GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --get

- INFO, Current server power state: On

- Supported values to set server power state:

On
ForceOff
ForceRestart
GracefulShutdown
PushPowerButton
Nmi

real	0m8.126s
user	0m0.218s
sys	0m0.021s

Shutdown Dell server via iDRAC python API

Let's see the examples of what we can do:

python GetSetPowerStateREDFISH.py --script-examples

- GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --get, this example will return current server power state and possible values supported to set power state.
    
- GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --set ForceRestart, this example will set server power state to ForceRestart.
    
- GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --set ForceOff --ssl true, this example uses ssl cert validation for Redfish calls to set server power state to Off.

There's a helpful --script-examples flag you can pass to python GetSetPowerStateREDFISH.py python GetSetPowerStateREDFISH.py. Though it does make you wonder why not have a man page / cli validation and be done with it.

Let's gracefully shutdown our Dell server using the python iDRAC api

Thanks to the examples, gracefully shutting down the physical servers is very simple also.

python GetSetPowerStateREDFISH.py -ip 192.168.0.120 -u root -p calvin --set GracefulShutdown

- INFO, setting new server power state to: GracefulShutdown

- PASS, status code 204 returned, server power state successfully set to "GracefulShutdown"

Let's make it web scale

Wrap the above in python + html, what to you get? A web console for your servers!

Naturally, I asked ChatGTP to help me with this: A web interface to turn on/off servers via the out of band management via a web based interface:

Code for the above: https://github.com/KarmaComputing/redfish-server-automation

import os
import subprocess
from flask import Flask, jsonify, render_template

app = Flask(__name__)

ip_address = os.getenv("IP_ADDRESS", "192.168.0.120")
username = os.getenv("IDRAC_USERNAME", "root")
password = os.getenv("IDRAC_PASSWORD", "calvin")


@app.route("/")
def index():
    return render_template("index.html")


def execute_redfish_command(action):
    command = [
        "python",
        "GetSetPowerStateREDFISH.py",
        "-ip",
        ip_address,
        "-u",
        username,
        "-p",
        password,
        "--set",
        action,
    ]
    result = subprocess.run(command, capture_output=True)
    return (
        jsonify(
            {
                "output": result.stdout.decode("utf-8"),
                "error": result.stderr.decode("utf-8"),
            }
        ),
        result.returncode,
    )


@app.route("/api/v1/On", methods=["POST"])
def set_power_on():
    return execute_redfish_command("On")


@app.route("/api/v1/GracefulShutdown", methods=["POST"])
def set_power_graceful_shutdown():
    return execute_redfish_command("GracefulShutdown")


if __name__ == "__main__":
    app.run()

app.py