6.4 Prepare and IPL Linux in an LPAR

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Note

If you are installing Linux under z/VM, you can skip this section and go to Section 6.5, "Linux installation and customization" on page 101.

It is possible to run Linux for zSeries natively in an LPAR (zSeries or S/390) as a standalone operating system. The install process for depends on the abilities of the Hardware Management Console (HMC) and the media types available.

Linux can be installed:

By IPLing from tape (see 6.4.4, "Tape preparation" on page 97)
By IPLing from DASD (see 6.4.5, "DASD preparation" on page 100)
From CD or the CD code available on FTP (see 6.4.6, "Booting Linux from the HMC" on page 101)

We cover the process of building an IPLable tape and a tape image on DASD for SUSE Linux SLES 8 for zSeries, IPLing Linux from the install media, and installing the Linux code. The actual installation and customization of Linux is the same, regardless of whether it is installed as a standalone OS in an LPAR or under VM.

When running Linux as a standalone operating system in its own LPAR, Linux is not running under some other operating system such as z/VM or z/OS-rather, it is run as a self-standing operating system on the zSeries or S/390 hardware.

A consideration when running Domino in a Linux LPAR is that the number of LPARs depends on the hardware. Other applications on the machine may reduce the number of LPARs available.

Another consideration is how busy the Domino application within the LPAR is projected to be. An underutilized Linux running in an LPAR can be a waste of resources. Linux running under z/VM can handle dynamic loads more readily and with greater optimization of resources.

6.4.1 Assumptions

This section is written for the person installing Linux and does not cover how to set up an LPAR on zSeries hardware. The following assumptions are made:

An LPAR has already been configured for Linux with the proper resources.
The person installing Linux has access to the Hardware Management Console (HMC).
The LPAR has access to a tape drive or a DASD which contains the IPL-able installation image of Linux.
The installer has access to the z/OS or z/VM operating system and is able to submit JCL and write to tape or DASD.
The z/OS operating system has FTP access to transfer files from a workstation or z/OS. This can be client access if the workstation is running an FTP server.

6.4.2 Skills needed

A variety of skills are needed to install Linux natively on zSeries hardware. These include the following:

A systems programmer or operations resource capable of creating an LPAR on the zSeries hardware.
A systems programmer or operations resource with access to the HMC.
A z/VM or z/OS user with the ability to FTP, run JCL, mount tapes, or create an IPL-able DASD volume. This person must also understand the operating system under which they are working.
- For VM, this means having a solid working knowledge of CMS and CP commands. This person should also have access to an ID with a high privilege class, allowing system-level operations. Knowledge of REXX is also a plus.
- The z/OS system programmer should have a solid working understanding of JCL, and have the access necessary to do system-level tasks
A Linux administrator knowledgeable about the installation and configuration of a Linux system.
A networking resource with a solid understanding of the local network and the connection options available on the zSeries hardware.

6.4.3 FTP installation files to z/OS

The first step in creating either an bootable Linux tape or disk is to acquire the three files needed from the distribution CD. Our CD was mounted on a Linux workstation and the FTP command was issued under TSO (ISPF option 6):

    ftp <workstation FTP server>    (enter id and password at prompt)    ftp> locsite lrecl=1024 blksize=8192 recfm=fb track pri=260 sec=50    ftp> bin    ftp> get    Remote file cd1/boot/initrd    Local file linux390.initrd    125 Storing data set <hilevqualifier>.LINUX390.INITRD    ftp> locsite lrecl=1024 recfm=f blksize=1024 track pri=1    ftp> get    Remote file get cd1/boot/parmfile    Local file linux390.parmfile    125 Storing data set <hilevqualifier>.LINUX390.PARMFILE    ftp> locsite recfm=fb lrecl=1024 blksize=8192 bl pri=200 sec=100    ftp> get    Remote file cd1/boot/tapeipl.ikr    Local file linux390.tapeipl.ikr    125 Storing data set <hilevqualifier>.LINUX390.TAPEIPL.IKR    ftp> quit

Here are the attributes of the files as they were created on the z/OS or OS/390 system:

    Dataset Name                    Tracks %Used Device Dsorg Recfm Lrecl Blksize    <hilevqualifier>.LINUX390.TAPEIPL   31   100   3390    PS    FB  1024    8192    <hilevqualifier>.LINUX390.INITRD   207   100   3390    PS    FB  1024    8192    <hilevqualifier>.LINUX390.PARMFILE   1   100   3390    PS     F  1024    1024

6.4.4 Tape preparation

The Linux install tape can be created from either z/VM or z/OS. These files need to have been transferred to the system you are using in order to create the tape:

The installation RAMdisk file-initrd
The parameter file-parmfile
The installation kernel-tapeipl.ikr

Creating an IPL tape on z/OS

The IEBGENER utility is used to create a tape from the installation files. Before transferring the files to tape, we created a null (empty) file with tape marks at the beginning of the tape. This destroyed any volume label that might have been on the tape.

In a typical z/OS or OS/390 production environment, you will have to bypass tape volume protection in order to write to the tape.

You must be able to specify the "bypass label processing" option (BLP) which was used on DD statement SYSUT2 in the sample job:

    //LINUXTP JOB (999,POK),'CREATE NL',NOTIFY=&SYSUID,    // CLASS=A,MSGCLASS=T,MSGLEVEL=(1,1)    //STEP0 EXEC PGM=IEBGENER    //SYSPRINT DD SYSOUT=*    //SYSUT1 DD DUMMY,DCB=(RECFM=F,BLKSIZE=1024)    //SYSUT2 DD DISP=(NEW,KEEP),LABEL=(1,BLP),DSN=SUSE.BOOT,    // DCB=(RECFM=F,LRECL=1024),VOL=SER=NLTAPE,    // UNIT=B4F    //SYSIN DD DUMMY    //

Other volume protection measures in effect by your installed tape management product may require additional DD statement parameters to be specified.

A boot tape can be created by running the GENER job shown:

    //LINUXTP JOB (999,POK),'CREATE BOOT TAPE',NOTIFY=&SYSUID,    // CLASS=A,MSGCLASS=T,MSGLEVEL=(1,1)    //IMAGE EXEC PGM=IEBGENER    //SYSPRINT DD SYSOUT=*    //SYSUT1 DD DISP=SHR,DSN=<hilevqualifier>.LINUX390.TAPEIPL.IRK    //SYSUT2 DD DISP=(NEW,PASS),LABEL=(1,NL),DSN=DUMMY,    // DCB=(RECFM=F,LRECL=1024),    // UNIT=B4F    //SYSIN DD DUMMY    //PARMLINE EXEC PGM=IEBGENER    //SYSPRINT DD SYSOUT=*    //SYSUT1 DD DISP=SHR,DSN=<hilevqualifier>.LINUX390.PARMFILE    //SYSUT2 DD DISP=(NEW,PASS),LABEL=(2,NL),DSN=DUMMY,    // DCB=(RECFM=F,LRECL=1024),    // VOL=(,RETAIN,,REF=*.IMAGE.SYSUT2),    // UNIT=B4F    //SYSIN DD DUMMY    //INITRD EXEC PGM=IEBGENER    //SYSPRINT DD SYSOUT=*    //SYSUT1 DD DISP=SHR,DSN=<hilevqualifier>.LINUX390.INITRD    //SYSUT2 DD DISP=(NEW,KEEP),LABEL=(3,NL),DSN=DUMMY,    // DCB=(RECFM=F,LRECL=1024),    // VOL=(,RETAIN,,REF=*.IMAGE.SYSUT2),    // UNIT=B4F    //SYSIN DD DUMMY    //

Note

There may be environments where a non-labelled tape is simply not possible. If you must write the Linux boot files to a standard-labelled tape, you must then issue the IPL command five times. The first four times will fail, but the label will be skipped over, and the fifth IPL should succeed.

Creating an IPL tape on VM

The following sequence of FTP commands were used to download the required boot files from a CD on a workstation to prepare a tape to be used as the media or boot of Linux from tape. Note that files are reblocked to a record length of 1024 bytes, and that the kernel file is specific to the tape boot method.

Log on to a virtual machine that has the appropriate class privileges to attach tape drives. IPL CMS, if it is not already running.

Access TCPMAINT's 592 disk to make FTP available to download the files tapeipl.ikr, parmfile, and initrd from the SLES8 distribution CD, as shown:

    link tcpmaint 592 592 rr    acce 592 d

The three files that will be downloaded are quite large and will be used only once to create the tape. We recommend placing them on temporary disk (TDISK) using the following commands to define and format the tdisk:

    def t3380 as 192 cyl 30    format 192 b    DMSFOR603R FORMAT will erase all files on disk B(192). Do you wish to continue?    Enter 1 (YES) or 0 (NO).    1    DMSFOR605R Enter disk label:    temp    Formatting disk B    30 cylinders formatted on B(192)

We allocated 30 cylinders of TDISK space, but later found that 15 cylinders of T3380 would have been enough.

FTP the tapeipl.ikr, initrd, and parmfile to the 192 TDISK you just created. We FTPed the files from a workstation running Linux with the SLES8 CD mounted and an FTP server. We used the FTP client in VM. The kernel and initial RAMdisk files must be blocked at 1024:

    ftp <ftp.server>    USER (identify yourself to the host): <joeuser>    locsite fix 1024    bin    >>>TYPE i    get cd1/boot/initrd SLES8.INITRD.B    8060928 bytes transferred in 90.287 seconds. Transfer rate 89.28 Kbytes/sec.    get cd1/boot/tapeipl.ikr SLES8.TAPEIPL.B    2328576 bytes transferred in 29.617 seconds. Transfer rate 78.62 Kbytes/sec.    asc    >>>TYPE a    get cd1/boot/parmfile SLES8.PARMFILE.B    54 bytes transferred in 0.017 seconds. Transfer rate 3.18 Kbytes/sec.    quit    221 Goodbye.

The files we downloaded to the 192 (B) disk were:

 LVL 0 - B 192      5400 BLKS 3390 R/W      3 FILES 46% FILE      1 OF      3 SLES8    INITRD   B1                 F  1024       7872    1968  8/25/03 13:47 SLES8    TAPEIPL  B1                 F  1024       2274     515  8/25/03 13:48 SLES8    PARMFILE B1                 V    52          1       1  8/25/03 13:50

Attach a tape drive to a virtual machine. The following CP command is an example of attaching the tape device B30, which must be issued from a privileged VM user ID:

    ATT B30 LINUXC AS 181

In this example, the user ID LINUXC now has a virtual device 181, which is the real tape drive B30. Insert a blank non-labelled tape and issue a rewind command to make sure the tape is rewound to the beginning:

    REW 181

Then the following commands will copy the files to tape:

    FILEDEF IN DISK SLES8 TAPEIPL B    FILEDEF OUT TAP1 (RECFM F LRECL 1024 BLOCK 1024 PERM)    movefile in out    FILEDEF IN DISK SLES8 PARM B    movefile in out    FILEDEF IN DISK SLES8 INITRD B    movefile in out

A REXX EXEC can also be created that will copy the boot files to the tape device 181:

    /* */    REW 181    'FILEDEF IN DISK SLES8 TAPEIPL B'    'FILEDEF OUT TAP1 (RECFM F LRECL 1024 BLOCK 1024 PERM)'    'movefile in out'    'FILEDEF IN DISK SLES8 PARMFILE B'    'movefile in out'    'FILEDEF IN DISK SLES8 INITRD B'    'movefile in out'

The tape can now be either unloaded using the TAPE RUN command, or can be rewound for an immediate IPL.

6.4.5 DASD preparation

An alternate method of installing Linux is to use the z/OS ICKDSF utility to install a bootstrap loader and the three Linux install files on DASD. Then you IPL from DASD rather than tape to do the initial installation. There is a tool available online that places a DASD Linux bootstrap program and the kernel, parmfile, and RAMdisk files on DASD using ICKDSF. This DASD volume can then be varied offline from the z/OS LPAR and IPLED from the Linux LPAR through the HMC. We found this to be the best method of installing Linux into an LPAR and would recommend it highly.

To install the initial Linux boot code, get the JCL for assembling the ICKDSF Linux bootstrap program and place it and the Linux install files on DASD. It is available from the author, Rob van der Heij, on the Web at:

http://www.rvdheij.com/linuxipl.html

Before using the JCL, check for the most recent copy at the Web site. For reference, we have included the JCL we ran in "The Linuxipl JCL" on page 365.

In addition to this JCL, the following three files must be downloaded using FTP from the SLES-8 distribution CD:

    initrd - Initializes a ramdisk image    parmfile - The installation parameter file    tapeipl.ikr - Installation kernel image

The sample JCL will set up the Linux bootstrap DASD to emulate tape, allowing an IPL from DASD. It will assemble the bootstrap, write a new VTOC on the volume, write the bootstrap records, and copy the three Linux data sets to the volume.

Run the JCL in dasd.JCL

Modify the LINUXIPL sample JCL to meet your organization standards. Modify the symbolics &linux and &UID to match the VOLSER of the DASD volume and the high level qualifier for the datasets containing the initrd, parmfile, and tapeipl.ikr files. Vary the address of the Linux boot device online to MVS. Submit the LINUXIPL JCL.

Upon successful completion of the JCL, vary address of Linux boot DASD offline to z/OS.

Although you will IPL from DASD, the device is not usable in Linux after the initial load. We recommend that you run dasdfmt against it and use it as your root device for Linux.

6.4.6 Booting Linux from the HMC

zSeries servers with the current microcode engineering level (MCEL) come with an integrated CD-ROM drive in the HMC. (The MCEL can be upgraded on your zSeries hardware in some cases.) The HMC is also enabled for FTP, and can be used for the initial load, provided there is network access to an FTP server on which the code is available.

The main advantage to loading the Linux code using one of these methods is that the Linux administrator does not have to depend on the availability of a person with skills in any of the mainframe operating systems; only knowledge of the HMC is needed. The CD-ROM drive on the HMC is used only to stage the kernel image, parameter file, and RAMdisk image. The installation files of your particular Linux distribution must still be "network reachable" from the target LPAR during the installation process. Once the kernel and RAMdisk are loaded, the installation process is the same, regardless of the kernel boot method used.

To start the process of booting Linux from the HMC, select the CPC that contains the Linux (IFL) LPAR. From the Images Work Area on the HMC, select the target LPAR on which Linux will be installed.

To initiate the load process, double-click the icon labeled Load from CD-ROM or Server. For a complete description of this process, see 3.4 in Linux for S/390 and zSeries: Distributions, SG24-6264, available on the Web at:

http://www.redbooks.ibm.com/abstracts/sg246264.html

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