Serial console via IPMI
When SSH is unavailable (broken network, firewall, boot failure), the serial console redirected by IPMI lets you administer the server as if you were at a KVM screen. Essential on HolyCloud dedicated servers.
Prerequisites
- IPMI/BMC address and credentials from the panel (or delivery email)
- Recent browser or
ipmitool/openipmi - VPN or allowed IP if BMC ACL is restricted
- Java disabled on most browsers — prefer HTML5 SOL (Serial Over LAN)
Web IPMI access
- HolyCloud panel → server → IPMI / BMC.
- Open
https://IP_BMC/(self-signed certificate). - BMC admin login (often a dedicated user, not Linux root).
- Menu Remote Control → Console Redirection or iKVM/HTML5.
- Launch the session; you see BIOS POST then OS boot.
Limit IPMI access to your fixed IP in BMC settings — high attack surface.
Serial console (SOL) with ipmitool
From a Linux workstation or management VPS:
sudo apt install -y ipmitool openssh-client
export BMC_IP=203.0.113.10
export BMC_USER=admin
export BMC_PASS='mot_de_passe_bmc'
# test
ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS chassis status
Enable SOL if needed (vendor-specific) then:
ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS sol activate
To exit: ~. or the sequence documented by the firmware.
Serial redirection in Linux (target)
On Debian, enable serial console for grub and login:
/etc/default/grub:
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"
GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
sudo update-grub
Systemd getty on serial:
sudo systemctl enable serial-getty@ttyS0
sudo systemctl start serial-getty@ttyS0
Speed 115200 must match BMC settings (often under Serial Port settings).
Use cases
| ----------- | ---------------- |
|---|---|
| Forgotten root password | Single-user mode / live ISO via virtual media |
Virtual media + serial
Combine virtual ISO (Debian netinst) and console to reinstall without the panel:
- IPMI → Virtual Media → mount ISO.
- Boot order CD first.
- Follow the installer in the HTML5 console.
BMC security
- Change the default BMC password immediately.
- Disable anonymous accounts, public SNMP.
- Update BMC firmware when HolyCloud publishes a recommendation.
- Do not expose the IPMI port on the Internet without a VPN tunnel.
# example: list IPMI users
ipmitool -I lanplus -H $BMC_IP -U $BMC_USER -P $BMC_PASS user list
Troubleshooting
| ---------- | ------- |
|---|---|
| Black SOL screen | Serial speed, sol activate vs iKVM |
| Session dropped | BMC timeout — increase in settings |
| IPMI unreachable | Management network, ACL, datacenter ticket |
| Garbage characters | Wrong baud rate (9600 vs 115200) |
Best practices
- Test the console before a major network migration.
- Document BMC IP and procedure for the team (password vault).
- After intervention,
sol deactivateand close the web session.
Need help?
HolyCloud can reset BMC access, verify management port connectivity, or replace a motherboard if SOL is hardware-faulty.