Debug step by step systemd boot process

This document (7023902) is provided subject to the disclaimer at the end of this document.

Environment


SUSE Linux Enterprise Server 12 Service Pack 3 (SLES 12 SP3)
SUSE Linux Enterprise Server 12 Service Pack 4 (SLES 12 SP4)
SUSE Linux Enterprise Server 15 Service Pack 1 (SLES 15 SP1)

Situation

Unpredicted changes or failing commands during boot process hidden by bootsplash or excessive logging.

Resolution

During boot when seeing grub boot menu press "e" for edit, then scroll down until you see your boot entry:
---snip---
    echo "Loading Linux...
    linux
---snap---

On the line with "linux" remove following entries if present:
splash=silent quiet showopts
then add following entries to get step by step booting including a early access shell on console 9:
 plymouth.enable=0 systemd.confirm_spawn=true systemd.debug-shell=1 systemd.log_level=debug systemd.unit=multi-user.target console=tty1
plymouth.enable=0 will disable plymouth bootsplash
systemd.confirm_spawn=true asks for confirmation when spawning processes
systemd.debug-shell=1 enables a root shell on console 9 (reachable via F9)
systemd.log_level=debug enables debug logging
systemd.unit=multi-user.target avoids switch to console 7 for output and input stays at console 1
console=tty1 avoids switch of input/ouput to console 9 where bash will get attached

With CTRL+x or F10 start "one time" booting with the given changes.
For testing purposes yo ucan also add those options to GRUB_CMDLINE_LINUX_DEFAULT:
/etc/default/grub
Depending on the keyboard layout accept each step with "z" (or "y") until "vconsol-setup" is confirmed, then with "y".
If issue has been found/fixed pressing "c" will continue without asking anymore

Cause


Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.

  • Document ID:7023902
  • Creation Date: 27-May-2019
  • Modified Date:03-Mar-2020
    • SUSE Linux Enterprise Server

< Back to Support Search

For questions or concerns with the SUSE Knowledgebase please contact: tidfeedback@suse.com

SUSE Support Forums

Get your questions answered by experienced Sys Ops or interact with other SUSE community experts.

Join Our Community

Support Resources

Learn how to get the most from the technical support you receive with your SUSE Subscription, Premium Support, Academic Program, or Partner Program.


SUSE Customer Support Quick Reference Guide SUSE Technical Support Handbook Update Advisories
Support FAQ

Open an Incident

Open an incident with SUSE Technical Support, manage your subscriptions, download patches, or manage user access.

Go to Customer Center