IPMI management

Knowledge: Reading time: 20 minutes

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Introduction¶

The Intelligent Platform Management Interface (IPMI) is an open standard for monitoring and managing server hardware independently of the operating system¹. IPMI communicates with the Baseboard Management Controller (BMC), a dedicated microcontroller embedded on the server motherboard. The BMC operates with its own firmware, network connection, and power supply, allowing administrators to monitor hardware health, control power states, and access a remote console even when the host operating system is unresponsive or powered off².

This guide covers installing and configuring IPMI tools on Rocky Linux, performing common management operations both locally and remotely, and troubleshooting the most frequent issues administrators encounter.

Prerequisites¶

A system running Rocky Linux 8, 9, or 10 with BMC/IPMI-capable hardware (most rack and tower servers from Dell, HPE, Supermicro, and Lenovo etc include a BMC).
Root or sudo access on the Rocky Linux host.
Network access to the BMC management interface (for remote operations).
The ipmitool or freeipmi packages (installation is covered below).

Installing IPMI tools¶

Install ipmitool with dnf:

sudo dnf install ipmitool

Verify the installation:

ipmitool -V

Loading IPMI kernel modules¶

Rocky Linux does not load IPMI kernel modules by default. Before you can use ipmitool locally, you must load the required modules.

Warning

If the IPMI kernel modules are not loaded, ipmitool will fail with the error: Could not open device at /dev/ipmi0 or /dev/ipmi/0 or /dev/ipmidev/0: No such file or directory. This is the most common IPMI issue on Rocky Linux.

Load the three core IPMI modules:

sudo modprobe ipmi_msghandler
sudo modprobe ipmi_devintf
sudo modprobe ipmi_si

ipmi_msghandler — the core IPMI message handler that provides the framework for IPMI communication³.
ipmi_devintf — creates the /dev/ipmi0 character device that user-space tools such as ipmitool use to communicate with the BMC³.
ipmi_si — the system interface driver that communicates with the BMC over the KCS (Keyboard Controller Style), SMIC, or BT interfaces³.

Verify the modules loaded:

lsmod | grep ipmi

Expected output on a server with BMC hardware:

ipmi_si                73728  0
ipmi_devintf           20480  0
ipmi_msghandler       106496  2 ipmi_devintf,ipmi_si

Persisting IPMI modules across reboots¶

The modules loaded with modprobe do not survive a reboot. To load them automatically at boot, create a configuration file in /etc/modules-load.d/:

cat << "EOF" | sudo tee /etc/modules-load.d/ipmi.conf
ipmi_msghandler
ipmi_devintf
ipmi_si
EOF

After creating this file, the systemd-modules-load service will load these modules on every boot.

Verifying the IPMI device¶

After loading the modules, verify that the /dev/ipmi0 device exists:

ls -la /dev/ipmi*

Check the kernel ring buffer for IPMI-related messages:

dmesg | grep -i ipmi

On a server with BMC hardware, you will see messages indicating that the IPMI system interface was found and the device was registered.

Test connectivity to the BMC:

sudo ipmitool mc info

This displays the BMC firmware version, manufacturer, and other management controller details.

Local and remote IPMI access¶

Local access¶

Local access uses the /dev/ipmi0 device to communicate directly with the BMC on the same machine:

sudo ipmitool <command>

Remote access¶

Remote access connects to a BMC over the network using the IPMI LAN interface. This is useful for managing servers from a central management station or head node:

ipmitool -H <BMC_IP> -I lanplus -U <username> -P <password> <command>

-H — the BMC IP address or hostname.
-I lanplus — use the IPMI v2.0 RMCP+ (LAN Plus) interface, which provides authentication and encryption¹.
-U — the BMC username.
-P — the BMC password.

Warning

Passing passwords on the command line exposes them in process listings and shell history. For scripted or production use, consider the -f flag to read the password from a file, or use the -E flag to read the password from the IPMI_PASSWORD environment variable.

Example checking the power status of a remote server:

ipmitool -H 192.168.1.100 -I lanplus -U admin -P password chassis power status

Common ipmitool operations¶

Sensor readings¶

View all sensor data with thresholds:

sudo ipmitool sensor list

View the Sensor Data Repository (SDR) for a compact summary:

sudo ipmitool sdr

Power control¶

sudo ipmitool chassis power status
sudo ipmitool chassis power on
sudo ipmitool chassis power off
sudo ipmitool chassis power cycle
sudo ipmitool chassis power reset

power cycle — turns the server off and then on again (hard power cycle).
power reset — performs a hardware reset without a full power cycle.

Chassis status¶

sudo ipmitool chassis status

This displays the current power state, last power event, and miscellaneous chassis status flags.

System Event Log (SEL)¶

The SEL records hardware events such as temperature threshold crossings, fan failures, and memory errors:

sudo ipmitool sel list

For a more detailed, human-readable output:

sudo ipmitool sel elist

To clear the SEL after reviewing events:

sudo ipmitool sel clear

Warning

Only clear the SEL after you have reviewed and recorded any important events. Once cleared, the events cannot be recovered.

Serial Over LAN (SOL)¶

SOL redirects the server's serial console over the IPMI LAN interface, giving you remote console access even when the network stack is not available:

ipmitool -H <BMC_IP> -I lanplus -U <username> -P <password> sol activate

To disconnect from the SOL session:

ipmitool -H <BMC_IP> -I lanplus -U <username> -P <password> sol deactivate

You can also press ~. to terminate the SOL session from the client side.

User management¶

List all users configured on BMC channel 1:

sudo ipmitool user list 1

Troubleshooting missing /dev/ipmi0¶

This section addresses the most common issue: ipmitool failing because /dev/ipmi0 does not exist.

Step 1 — Check that the IPMI modules are loaded¶

lsmod | grep ipmi

If no output appears, load the modules as described in the Loading IPMI kernel modules section above.

Step 2 — Check dmesg for errors¶

dmesg | grep -i ipmi

Look for messages such as:

ipmi_si: Unable to find any System Interface(s) — this means the kernel could not detect a BMC. Verify that your hardware has a BMC and that IPMI is enabled in the BIOS/UEFI settings.
ipmi_si: Trying KCS-defined... success — the interface was found successfully.

Step 3 — Restart the IPMI service¶

If the OpenIPMI service is installed, restart it:

sudo systemctl restart ipmi

If the service does not exist, you can install it:

sudo dnf install OpenIPMI
sudo systemctl enable --now ipmi

Step 4 — Verify BIOS/UEFI settings¶

If the modules load but no BMC is detected:

Enter the BIOS/UEFI setup during boot.
Navigate to the IPMI or BMC configuration section.
Ensure that IPMI over KCS is enabled.
Save changes and reboot.

Warning

Virtual machines and cloud instances typically do not have physical BMC hardware. The IPMI modules will load, but ipmitool will report that no BMC is found. IPMI requires physical server hardware with an embedded BMC.

Step 5 — Check for conflicting drivers¶

On some systems, the ipmi_si module may conflict with vendor-specific management drivers. If you see errors in dmesg, try unloading and reloading the modules:

sudo modprobe -r ipmi_si ipmi_devintf ipmi_msghandler
sudo modprobe ipmi_msghandler
sudo modprobe ipmi_devintf
sudo modprobe ipmi_si

FreeIPMI as an alternative¶

FreeIPMI is an alternative IPMI implementation that provides its own set of command-line tools⁴. Some administrators prefer FreeIPMI for its detailed output formatting and additional features.

Installation¶

sudo dnf install freeipmi

Key FreeIPMI commands¶

FreeIPMI command	ipmitool equivalent	Description
`bmc-info`	`ipmitool mc info`	Display BMC information
`ipmi-sensors`	`ipmitool sensor list`	List all sensor readings
`ipmi-sel`	`ipmitool sel list`	Display the System Event Log
`ipmi-chassis --get-chassis-status`	`ipmitool chassis status`	Display chassis status
`ipmipower --stat`	`ipmitool chassis power status`	Check power status
`ipmipower --on`	`ipmitool chassis power on`	Power on the server
`ipmipower --off`	`ipmitool chassis power off`	Power off the server

FreeIPMI tools also support remote access with the -h, -u, and -p flags:

bmc-info -h <BMC_IP> -u <username> -p <password>

BMC firmware update considerations¶

Danger

BMC firmware updates carry risk. A failed or interrupted firmware update can render the BMC unresponsive, potentially requiring a physical board replacement. Always follow your hardware vendor's instructions exactly.

General guidance for BMC firmware updates:

Download firmware only from your server vendor's official support site (Dell, HPE, Supermicro, Lenovo).
Read the release notes for the firmware version before applying the update.
Ensure stable power throughout the update process. Use a UPS if available.
Do not reboot or power off the server during the firmware update.
Back up the current BMC configuration before updating, if your vendor's tools support this.

Most vendors provide their own BMC firmware update utilities:

Dell: racadm or Dell EMC Repository Manager.
HPE: ilorest or HPE Smart Update Manager.
Supermicro: sum (Supermicro Update Manager) or web-based BMC interface.
Lenovo: OneCLI or Lenovo XClarity.

Conclusion¶

You now have a working IPMI configuration on Rocky Linux for managing server hardware locally and remotely. The key steps covered include loading and persisting the required kernel modules³, using ipmitool for common management tasks¹, troubleshooting the most frequent /dev/ipmi0 issues, and using FreeIPMI as an alternative⁴.

For deeper exploration of the IPMI specification and advanced features, refer to the Intel IPMI specification¹ and the ipmitool repository².

References¶

"Intelligent Platform Management Interface Specification, Second Generation, v2.0" by Intel Corporation https://www.intel.com/content/dam/www/public/us/en/documents/product-briefs/ipmi-second-gen-interface-spec-v2-rev1-1.pdf
"ipmitool — utility for controlling IPMI-enabled devices" by Duncan Laurie and contributors https://github.com/ipmitool/ipmitool
"IPMI — The Linux Kernel documentation" by Corey Minyard https://www.kernel.org/doc/html/latest/driver-api/ipmi.html
"FreeIPMI — GNU Project" by Albert Chu and the GNU FreeIPMI Team https://www.gnu.org/software/freeipmi/

Author: Howard Van Der Wal

Contributors: Steven Spencer