Power, cooling and the HMC network

You’ll set up the way you’ll connect to the DS8000 every day, a profile that knows both HMCs, then check the HMCs and their remote access and test your networks against the private HMC ranges.

Practice shell note: the practice shell is our teaching tool, not IBM software, and real DS CLI output is similar but not identical. The shell accepts any HMC address and has no real network behind it, so it can’t show a dead HMC; on a real system the DS CLI falls over to hmc2. The HMC names and location codes are made up for the lab.

1Write a DS CLI profile with both HMCs

In your lab folder, create a text file called lab.profile with these lines. The real DS CLI uses the same name: value style in its profile.

lab.profile:

# lab.profile - DS CLI profile for the SaatVedha lab DS8A50
hmc1: 10.0.0.1
hmc2: 10.0.0.2
username: admin
devid: IBM.2107-78SV001

✅ Checkpoint: lab.profile sits next to ds8sim.py.

2Look at the two HMCs

Use the profile with -cfg, so the only thing you add is your password.

Run this (PowerShell):

python ds8sim.py -cfg lab.profile -passwd YOURPASSWORD lshmc

You should see this:

Date/Time: 24 October 2026 13:55:50 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
Name          State  Role         Release                  Management-IP Location-Code    Machine-Type Machine-Model Memory Disk
================================================================================================================================
DS8A50-1A.LAB Online Primary(1)   R10.1 bundle 10.10.106.0 10.0.0.1      U7063CR2.78SV1DD 7063         CR2           33GB   1TB
DS8A50-1B.LAB Online Secondary(2) R10.1 bundle 10.10.106.0 10.0.0.2      U7063CR2.78SV2DD 7063         CR2           33GB   1TB

Both are type 7063-CR2, both Online and on the same code bundle. Management-IP is the customer network address you reach them on, and the private black and gray addresses never show up here. On a real system, check after every code load that both HMCs show the same release.

✅ Checkpoint: Both HMCs are Online, primary and secondary.

3Check which access doors are open

Run this:

python ds8sim.py -cfg lab.profile -passwd YOURPASSWORD lsaccess -l

You should see this:

Date/Time: 24 October 2026 13:55:50 UTC IBM DSCLI Version: 7.10.10.348 DS: IBM.2107-78SV001
hmc  cmdline wui     modem    cim      aos     rsc     vpn
===============================================================
hmc1 enabled enabled disabled disabled enabled enabled disabled
hmc2 enabled enabled disabled disabled enabled enabled disabled

cmdline is DS CLI access and wui is the web interface, while aos (Assist On-site) and rsc (Remote Support Console) are the two ways IBM support can connect in. On a real system you change these with chaccess, for example chaccess -aos enable -hmc 1, but the practice shell only lists them. A lot of security teams keep remote support off until a case is open.

✅ Checkpoint: You can say which remote support methods are enabled on each HMC.

4Check your networks against the private ranges

Before installation, the network team gives you every subnet the HMCs will be able to reach. Save this checker as hmc_netcheck.py on your laptop, in the lab folder next to ds8sim.py; it’s a planning tool that runs there, not on the DS8000 or the HMC, and it tests your subnets against the four private range choices in IBM’s table. Step 5 uses its --check part.

# hmc_netcheck.py - SaatVedha check: do your networks clash with the DS8A00 private HMC networks?
# A planning tool: it runs on your laptop or jump server, not on the DS8000 or the HMC.
# With --check it also reads both HMCs through the DS CLI with lshmc
# (auto.profile: banner off, header on, format delim) and tests their Management-IP addresses.
# Ranges from the IBM Redbook SG24-8559-01, table "Private networks" (black = eth0, gray = eth3).
# Usage: python hmc_netcheck.py <your subnet> [<your subnet> ...]    for example 172.16.40.0/22
#        python hmc_netcheck.py --check [<your subnet> ...]
import csv, ipaddress, subprocess, sys
DSCLI = ["python", "ds8sim.py", "-cfg", "auto.profile"]   # at work: ["dscli", "-cfg", "auto.profile"]

def dscli(*args):
    """Run one DS CLI command and return its rows as dictionaries."""
    out = subprocess.run(DSCLI + list(args), capture_output=True, text=True).stdout
    lines = [l for l in out.splitlines() if l and not l.startswith("SaatVedha") and not l.startswith("CMUC")]
    return list(csv.DictReader(lines))

OPTIONS = {
    "Default":  ("172.16.0.0-172.16.255.255", "172.17.0.0-172.17.255.255"),
    "Option 1": ("10.235.0.0-10.235.2.255", "10.236.0.0-10.236.2.255"),
    "Option 2": ("192.168.160.0-192.168.162.255", "192.168.240.0-192.168.242.255"),
    "Option 3": ("9.15.0.0-9.15.2.255", "9.16.0.0-9.16.2.255"),
}

def nets(rng):
    a, b = (ipaddress.ip_address(x) for x in rng.split("-"))
    return list(ipaddress.summarize_address_range(a, b))

args = sys.argv[1:]
yours = []
if args and args[0] == "--check":
    args = args[1:]
    hmcs = dscli("lshmc")
    if not hmcs:
        print("No answer from the DS CLI. Check auto.profile and the password file.")
        sys.exit(2)
    for h in hmcs:
        print(f"HMC {h['Name']}: {h['Management-IP']}, {h['State']}, {h['Role']}, {h['Release']}")
        yours.append(ipaddress.ip_network(h["Management-IP"]))
    if len({h["Release"] for h in hmcs}) > 1:
        print("WARNING : the HMCs run different releases. Check the last code load.")
    for h in hmcs:
        if h["State"] != "Online":
            print(f"WARNING : {h['Name']} is {h['State']}. You are down to one HMC.")
elif not args:
    print("Usage: python hmc_netcheck.py <your subnet> [<your subnet> ...]")
    print("       python hmc_netcheck.py --check [<your subnet> ...]")
    sys.exit(1)

yours += [ipaddress.ip_network(s, strict=False) for s in args]
safe = []
for name, (black, gray) in OPTIONS.items():
    clashes = [f"{y} overlaps {label}" for label, rng in (("black", black), ("gray", gray))
               for y in yours if any(y.overlaps(n) for n in nets(rng))]
    if clashes:
        print(f"{name:8}: CLASH  - " + "; ".join(clashes))
    else:
        print(f"{name:8}: ok")
        safe.append(name)
print("Safe choices:", ", ".join(safe) if safe else "none - talk to IBM support")

Run this:

python hmc_netcheck.py 10.20.0.0/16 192.168.1.0/24

You should see this:

Default : ok
Option 1: ok
Option 2: ok
Option 3: ok
Safe choices: Default, Option 1, Option 2, Option 3

✅ Checkpoint: Your example networks are safe with the default 172.16 and 172.17 ranges.

5Check the installed HMCs

After installation you can test the real HMC addresses as well. --check reads both HMCs with lshmc through the DS CLI, tests their Management-IP addresses against the private ranges, and warns you if an HMC is down or the two are on different releases.

Your lab.profile still needs -passwd, and a script can’t answer password prompts, so save the password in a password file first. If security.dat is already in your lab folder from an earlier lesson, skip this command (the shell would tell you the record already exists).

Run this (PowerShell):

python ds8sim.py -cfg lab.profile -passwd YOURPASSWORD managepwfile -action add -name admin -pw YOURPASSWORD -pwfile security.dat

You should see this:

CMUC00206I managepwfile: Record 10.0.0.1/admin successfully added to password file security.dat.

Then save these eight lines as auto.profile in the same folder. banner: off, header: on and format: delim make every list come back as one header row plus comma-separated rows, which Python reads easily. Implementation Lesson 2 explains profiles in full.

auto.profile:

hmc1: 10.0.0.1
username: admin
pwfile: security.dat
devid: IBM.2107-78SV001
banner: off
header: on
format: delim
delim: ,

Run this (PowerShell):

python hmc_netcheck.py --check

You should see this:

HMC DS8A50-1A.LAB: 10.0.0.1, Online, Primary(1), R10.1 bundle 10.10.106.0
HMC DS8A50-1B.LAB: 10.0.0.2, Online, Secondary(2), R10.1 bundle 10.10.106.0
Default : ok
Option 1: ok
Option 2: ok
Option 3: ok
Safe choices: Default, Option 1, Option 2, Option 3

Both HMC addresses, 10.0.0.1 and 10.0.0.2, are outside every private range, and both HMCs are Online on the same bundle. You can add your own subnets after --check to test them along with the HMC addresses.

At work you run --check after every HMC change or code load, and the plain mode stays your tool for each new subnet the network team plans.

✅ Checkpoint: --check lists both HMCs and finds no clash for 10.0.0.1 and 10.0.0.2.