Re: Single user (rescue target) in SLES 12

[Mark Post]

>>> On 7/5/2017 at 09:29 AM, Steffen Maier  wrote: 
-snip-
> Doesn't this take you to single user mode of the "auxiliary" 
> kernel, i.e. the one of grub2-s390x-emu, rather than your 
> "target" / production kernel which can be quite different?

No, it doesn't.  It takes you to the production system.


Mark Post

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Re: Single user (rescue target) in SLES 12

[Steffen Maier]

On 06/27/2017 12:34 AM, Marcy Cortes wrote:

Thanks!  That is easy to remember!



-Original Message-
From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Mark Post
Sent: Monday, June 26, 2017 3:15 PM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: [LINUX-390] Single user (rescue target) in SLES 12


On 6/26/2017 at 03:26 PM, Marcy Cortes  wrote:

One thing I haven't figured out in SLES 12 systemd system is how to
boot into single user mode (rescue.target)?
On sles 11, I just did a #cp vi vmsg 1 1

Anyone know?


You should be able to do this:
IPL devno PARM S


Doesn't this take you to single user mode of the "auxiliary" 
kernel, i.e. the one of grub2-s390x-emu, rather than your 
"target" / production kernel which can be quite different?


[Similarly with SCPDATA instead of PARM if you would IPL from FCP/SCSI 
instead of from DASD.]


https://www.ibm.com/support/knowledgecenter/linuxonibm/com.ibm.linux.z.lhdd/lhdd_c_ipl_vs_boot.html

CAVEAT:
https://www.ibm.com/support/knowledgecenter/linuxonibm/com.ibm.linux.z.lhdd/lhdd_c_parms_spec.html#parms_caution__section_bad_kparms


I only know of grub2-s390x-emu support to select a particular grub.conf 
menu entry.


https://www.ibm.com/support/knowledgecenter/linuxonibm/com.ibm.linux.z.lhdd/lhdd_t_grub2_parms.html


For any other dynamic changing of kernel parameters for the target 
kernel, I only know of the interactive grub2 prompt.


https://www.suse.com/documentation/sles-12/book_sle_admin/data/sec_grub2_zseries.html

https://www.suse.com/documentation/sles-12/book_sle_admin/data/sec_grub2_file_structure.html#sec_grub2_menu_change

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Re: Single user (rescue target) in SLES 12

[Mark Post]

>>> On 6/27/2017 at 09:33 AM, Dave Jones  wrote: 
> Hi, Mark.
> 
> Is there a list or doc someplace that has all of the valid PARM values
> for IPL-ing SLES 12 in addition to the "PARM S" for getting into single
> user mode?

Mostly they're just kernel parameters, so 
/usr/src/linux/Documentation/kernel-parameters.txt would be one place. Then 
there are dracut and systemd parameters that can be passed, but I'm not aware 
of a consolidated place they're all discussed.


Mark Post

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Re: Single user (rescue target) in SLES 12

[Ray Mansell]

On the subject of #CP VI VMSG... my brain/finger combination often had
problems trying to enter the command I wanted before the timeout
occurred. Eventually it dawned on me that I could enter '#CP' on its own
(or use PA1) to enter CP READ, after which I could take my time entering
the VI VMSG command correctly before restarting the virtual machine.

I'm sure this is old news to many of you, but I thought it worth
mentioning.

Ray

On 2017-06-26 15:26, Marcy Cortes wrote:

> One thing I haven't figured out in SLES 12 systemd system is how to boot into 
> single user mode (rescue.target)?
> On sles 11, I just did a #cp vi vmsg 1 1
>
> Anyone know?
>
> Marcy
>
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Re: Single user (rescue target) in SLES 12

[Dave Jones]

Hi, Mark.

Is there a list or doc someplace that has all of the valid PARM values
for IPL-ing SLES 12 in addition to the "PARM S" for getting into single
user mode?
Thanks.
DJ

On 06/26/2017 05:14 PM, Mark Post wrote:
> PARM S

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Re: Single user (rescue target) in SLES 12

[Marcy Cortes]

Thanks!  That is easy to remember!


-Original Message-
From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Mark Post
Sent: Monday, June 26, 2017 3:15 PM
To: LINUX-390@VM.MARIST.EDU
Subject: Re: [LINUX-390] Single user (rescue target) in SLES 12

>>> On 6/26/2017 at 03:26 PM, Marcy Cortes  
>>> wrote: 
> One thing I haven't figured out in SLES 12 systemd system is how to 
> boot into single user mode (rescue.target)?
> On sles 11, I just did a #cp vi vmsg 1 1
> 
> Anyone know?

You should be able to do this:
IPL devno PARM S

There are systemd specific parms you can pass, but I find this much easier to 
remember.


Mark Post

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Re: Single user (rescue target) in SLES 12

[Mark Post]

>>> On 6/26/2017 at 03:26 PM, Marcy Cortes  
>>> wrote: 
> One thing I haven't figured out in SLES 12 systemd system is how to boot into 
> single user mode (rescue.target)?
> On sles 11, I just did a #cp vi vmsg 1 1
> 
> Anyone know?

You should be able to do this:
IPL devno PARM S

There are systemd specific parms you can pass, but I find this much easier to 
remember.


Mark Post

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