linux boot不成功如何debug

If the boot process does not succeed, you have several options to debug the situation.

Identifying your problem area

1. Remove ''rhgb'' and ''quiet'' from the kernel command line

2. Add ''rd.shell'' to the kernel command line. This will present a shell should dracut be unable to locate your root device

3. Add ''rd.shell rd.debug log_buf_len=1M'' to the kernel command line so that dracut shell commands are printed as they are executed

4. The file /run/initramfs/rdsosreport.txt is generated, which contains all the logs and the output of all significant tools, which are mentioned later.

If you want to save that output, simply mount /boot by hand or insert an USB stick and mount that. Then you can store the output for later inspection.