How to boot up in single user mode or other run levels

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Environment

SUSE Linux Enterprise Server 11
SUSE Linux Enterprise Server 10
SUSE Linux Enterprise Server 9
SUSE Linux Enterprise Desktop 11
SUSE Linux Enterprise Desktop 10

Situation

Under certain circumstances, the system needs to be booted up in single user or other run levels.

Resolution

On SUSE Linux, the method of starting a server in different run levels is similar. SLE 10 and 11 support the SLE 9 methods.

SLE 9
When the boot loader screen is presented type:

"single" for single user mode
"init X", where X is the run level number that needs to be booted
"/bin/bash" for more advanced rescue methods and where init or inittab is bad

SLE 10 and 11
When the boot loader screen is presented type:

"s" or "single" for single user mode
"X" or "init X", where X is the run level number that needs to be booted
"/bin/bash" for more advanced rescue methods and where init or inittab is bad

Xen para-virtual SLE (all versions), first method
This method uses the legacy installation file. Any hardware changes made to a managed domain via "YaST", "virt-manager" or "xm commands" will not be present. Replace "DOMU" with the name of your DomU.

Go to "/etc/xen/vm"
Locate the installation file, usually the name of the Xen DomU
Use the "xm create" command. (The "-c" will connect to the console, and "xencons=xvc0" will use the Xen frame buffer for SLES 10 SP1 and higher, and SLES 9 SP4. Use "xencons=tty" for SLES 10).
xm create -c DOMU extra=" init 1 xencons=xvc0"
Shutdown the DomU after making changes
Start the DomU normally

Xen para-virtual SLE (all versions), second method
This method uses the managed domain configuration store in the XenStore. This method should be used when a hardware change has been made using "YaST", "virt-manager" or "xm commands." If you are are unsure as to what method to use, use this method. Replace DOMU with the name of your DomU.

Export the configuration for the DomU.
"xm list -l DOMU > domu.py"
Start the DomU using the "xm create" command. (The "-c" will connect to the console, and "xencons=xvc0" will use the Xen frame buffer for SLES 10 SP1 and higher, and SLES 9 SP4. Use "xencons=tty" for SLES 10).
xm create -c -F domu.py extra=" single xencons=xvc0"
Shutdown the DomU after making changes
Start the DomU normally

Commonalities
Under all versions of SLES, booting into single user mode will present the user with a prompt for the root password.

Disclaimer

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