Hi everyone,
I’m having trouble using rcons via goconserver on Supermicro AS -1024US-TRT
servers running with xCAT 2.16.5 and Oracle Linux 8.8, booting in UEFI mode
with BLS enabled.
The issue is that after the GRUB menu, the SOL (Serial Over LAN) console
goes black and doesn’t show any kernel messages or login prompt via rcons.
The BIOS POST and GRUB appear just fine.
Below is the full setup to give context. I’d appreciate any tips or if
someone has faced a similar issue.
Environment:
- Server: Supermicro AS -1024US-TRT
- BMC: AST2500
- BIOS with SOL over COM1
- xCAT: 2.16.5
- Headnode OS: Oracle Linux 8.8
- Node OS: Oracle Linux 8.8
- Boot mode: UEFI with BLS (/boot/loader/entries/)
- IPMI management: cons=ipmi, mgt=ipmi
- rcons backend: goconserver
BIOS*:*
- COM1 Console Redirection: Enabled
- SOL Redirection: Enabled
- Redirection After BIOS POST: Always Enable
- Legacy Serial Redirection Port: COM1
- Baud Rate: 115200
- Terminal Type: VT100+
GRUB (/etc/default/grub):
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR="$(sed 's, release .*$,,g' /etc/system-release)"
GRUB_DEFAULT=saved
GRUB_DISABLE_SUBMENU=true
GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --speed=115200"
GRUB_CMDLINE_LINUX="crashkernel=auto
rd.md.uuid=852f7037:11485f13:1661da7f:6319b34d
rd.md.uuid=0e85274f:6be9a886:94b8e24f:12755dae console=ttyS0,115200"
GRUB_DISABLE_RECOVERY="true"
GRUB_ENABLE_BLSCFG=true
serial-getty is running:
serial-getty@ttyS0.service - Serial Getty on ttyS0
Loaded: loaded (/usr/lib/systemd/system/serial-getty@.service;
enabled-runtime; vendor preset: disabled)
Active: *active (running)* since Fri 2025-05-16 17:09:06 -03; 5 days ago
Docs: man:agetty(8)
man:systemd-getty-generator(8)
http://0pointer.de/blog/projects/serial-console.html
Main PID: 5679 (agetty)
Tasks: 1 (limit: 2884372)
Memory: 308.0K
CGroup:
/system.slice/system-serial\x2dgetty.slice/serial-getty@ttyS0.service
└─5679 /sbin/agetty -o -p -- \u --keep-baud 115200,38400,9600
ttyS0 vt220
May 16 17:09:06 localhost.localdomain systemd[1]: Started Serial Getty on
ttyS0
Serial device detected by the kernel, dmesg | grep tty:
[ 0.000000] Command line:
BOOT_IMAGE=(mduuid/0e85274f6be9a88694b8e24f12755dae)/vmlinuz-4.18.0-477.21.1.el8_8.x86_64
root=UUID=fa4950bb-e48d-422a-8a46-0e05ae3235ff ro crashkernel=auto
rd.md.uuid=852f7037:11485f13:1661da7f:6319b34d
rd.md.uuid=0e85274f:6be9a886:94b8e24f:12755dae console=*tty*S0,115200
[ 0.000000] Kernel command line:
BOOT_IMAGE=(mduuid/0e85274f6be9a88694b8e24f12755dae)/vmlinuz-4.18.0-477.21.1.el8_8.x86_64
root=UUID=fa4950bb-e48d-422a-8a46-0e05ae3235ff ro crashkernel=auto
rd.md.uuid=852f7037:11485f13:1661da7f:6319b34d
rd.md.uuid=0e85274f:6be9a886:94b8e24f:12755dae console=*tty*S0,115200
[ 0.001000] printk: console [*tty*S0] enabled
[ 10.922314] 00:03: *tty*S0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is
a 16550A
[ 10.950427] 00:04: *tty*S1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is
a 16550A
What’s happening:
- rcons shows BIOS POST and GRUB normally
- After GRUB, the console goes black
- No kernel messages or login prompt appear
- The system boots fine (verified via SSH and BMC console)
- echo "test" > /dev/ttyS0 does not output anything to rcons
Questions:
1. Could BLS be preventing the console= parameters from being applied
properly to the kernel?
2. Would it be better to disable BLS (GRUB_ENABLE_BLSCFG=false) and use
the traditional /boot/grub2/grub.cfg instead?
3. Is there any specific configuration required for goconserver or xCAT
to work correctly with Supermicro servers in UEFI mode?
4. Has anyone experienced this issue with Supermicro AST2500 BMCs and
serial redirection?
Any help or insight would be much appreciated. I can share more logs or
test additional changes if needed.
Thanks!
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