Laboratory environment

In the following sections, we describe the Linux-HA release 2 laboratory where we deployed SLES 10 and Red Hat Enterprise Linux 5 on z/VM. We provide details about how z/VM hosts were networked and how they share storage space. We also demonstrate how the z/VM network and storage are viewed from the perspective of z/VM guests and how DNS is used to set up names for these guests. The objective is to give you a glimpse of what is needed to start

deploying Linux-HA release 2 on Linux systems running under z/VM.

4.2.1 z/VM hosts and guests

In our environment, we use an IBM System z10 Enterprise Class for the hardware. We also used a hypervisor of z/VM version 5.4.

This environment consists of two LPARs. Each LPAR runs a z/VM host,

VMLINUX2 and VMLINUX9. In addition, each z/VM host runs four Linux guests.

In VMLINUX2 we installed guests lnxsu1, lnxsu2, lnxrh1, and lnxrh2. Guests lnxsu1 and lnxsu2 are SLES 10 z/VM guests, and guests lnxrh1 and lnxrh2 are Red Hat Enterprise Linux 5 z/VM guests.

In VMLINUX9, we installed guests lnxsu3, lnxsu4, lnxrh3, and lnxrh4. Guests lnxsu3 and lnxsu4 are SLES 10 z/VM guests, and guests lnxrh3 and lnxrh4 are Red Hat Enterprise Linux 5 z/VM guests.

4.2.2 Network setup

z/VM guests are networked by using two different z/VM features: HiperSockets and virtual switch (VSWITCH).

HiperSockets are used for the internal communication between the guests. On the Linux guests, the interface connected to HiperSockets is presented as hsi0.

The virtual switch is used by the guests for external communication. On Linux guests, the interface connected to the virtual switch is presented as eth0.

Example 4-1 shows the network setup for the z/VM guest’s side.

Example 4-1 Network setup on z/VM guest

00: CP 00: q lan

00: LAN SYSTEM HIPER1 Type: HIPERS Connected: 0 Maxconn:

INFINITE

00: PERSISTENT UNRESTRICTED IP MFS: 16384 Accounting:

OFF

00: IPTimeout: 5 00: VSWITCH SYSTEM VSWITCH1 Type: VSWITCH Connected: 4 Maxconn:

INFINITE 00: RDEV: 3024.P00 VDEV: 3024 Controller: DTCVSW2 BACKUP

The virtual switch is on production network 9.12.5.0/24 and on HiperSockets heartbeat network 9.12.5.0/24. For more information about how HiperSockets works, see “HiperSockets” on page 48.

4.2.3 Shared disk setup

Some of the scenarios in this book require a shared disk that is accessible by the nodes. This means that more than one z/VM guest must be able to read and write to the same device at the same time.

Our z/VM hosts shared a common IBM DS-8000 storage through an ESCON/FICON channel. This functionality is provided by the z/VM host.

Example 4-2 and Example 4-3 on page 62 list the disks in lnxsu3 and lnxsu4.

They show that the disk number 0203 has the same volume ID on both guests.

Example 4-2 DASDs on LNXSU3

00: CP

00: DASD 0201 3390 LXDF1B R/W 1000 CYL ON DASD DF1B SUBCHANNEL = 000F

00: DASD 0202 3390 LXDF1B R/W 9016 CYL ON DASD DF1B SUBCHANNEL = 0010

00: DASD 0203 3390 LXCF46 R/W 3338 CYL ON DASD CF46 SUBCHANNEL = 0011

00: DASD 0592 3390 LX9W02 R/O 70 CYL ON DASD CF44 SUBCHANNEL = 000D

Example 4-3 DASDs on LNXSU4

00: CP 00: q dasd 00: DASD 0190 3390 LX9RES R/O 107 CYL ON DASD CF40 SUBCHANNEL = 000A

00: DASD 0191 3390 LX9U1R R/W 40 CYL ON DASD CF45 SUBCHANNEL = 000F

00: DASD 019D 3390 LX9W01 R/O 146 CYL ON DASD CF43 SUBCHANNEL = 000C

00: DASD 019E 3390 LX9W01 R/O 250 CYL ON DASD CF43 SUBCHANNEL = 000B

00: DASD 0201 3390 LXD81E R/W 1000 CYL ON DASD D81E SUBCHANNEL = 0010

00: DASD 0202 3390 LXD81E R/W 9016 CYL ON DASD D81E SUBCHANNEL = 0011

00: DASD 0203 3390 LXCF46 R/W 3338 CYL ON DASD CF46 SUBCHANNEL = 000E

00: DASD 0592 3390 LX9W02 R/O 70 CYL ON DASD CF44 SUBCHANNEL = 000D

Figure 4-2 summarizes the laboratory environment used in this book.

Figure 4-2 Lab Environment

4.2.4 FTP server for the SLES 10 and Red Hat Enterprise Linux 5 packages repository

We set up an FTP server to work as a package repository for SLES 10 and Red Hat Enterprise Linux 5. This FTP has a unique IP address, and a user and password were used to gain access to the server.

Packages for SLES 10 are in the /code/sles10x-sp2/suse/s390x directory.

Packages for Red Hat Enterprise Linux 5 are in the /code/rhel5.2-s390x/Server directory. Virtual Switch ( used for 9.12.5.0 network )

OSA Express

External Network

Using the FTP server as a YaST repository for SLES 10

To add the FTP server as a package repository for SLES 10, start YaST2. In the YaST Control Center window (Figure 4-3), in the left pane, click Software, and in the right pane, click Installation Source.

Figure 4-3 Adding an installation source on YaST

After you open the Installation Source window, use the access information for the FTP server to complete the fields.

Using the FTP server as a YUM repository for Red Hat Enterprise Linux 5

We used Yellowdog Updater, Modified (YUM) to install RedHat Package Manager (RPM™) packages on RedHat Enterprise Linux.

To add the FTP server as a package repository for Red Hat Enterprise Linux 5, create the /etc/yum.repos.d/itso.repos file. Then insert the contents shown in Example 4-4 on page 65 into this file.

Example 4-4 Contents to insert into the /etc/yum.repos.d/itso.repo file

# cd /etc/yum.repos.d

# cat itso.repo [ITSO-repository]

name=ITSO-repository $releasever - $basearch - Debug

baseurl=ftp://totibm:[email protected]/code/rhel5.2-s390x/Server enabled=1

gpgcheck=1

gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

#

Run YUM on each Red Hat Enterprise Linux 5 z/VM to update its repositories list, as shown in Example 4-5.

Example 4-5 Updating the YUM repositories

# yum update

Loading "rhnplugin" plugin Loading "security" plugin

This system is not registered with RHN.

RHN support will be disabled.

4.2.5 DNS server for node name resolution

We set up a DNS service on the Linux guest lnxrh4.itso.ibm.com and configured all nodes to use it for primary name resolution. We chose

itso.ibm.com for the main domain namespace and in-addr.arpa for the reverse domain namespace.

Table 4-1 shows the details of the configuration.

Table 4-1 DNS configuration

4.2.6 Package selection for a Linux installation

This section describes the packages that were selected for our SLES10 and Red Hat Enterprise Linux 5 installations. The packages that are selected give optimal support for our Linux-HA release 2 installation.

SLES 10 installation

SLES 10 was deployed on nodes lnxsu1, lnxsu2, lnxsu3, and lnxsu4 using the default package selection. For more information about how to install SLES on the IBM System z platform, see z/VM and Linux on IBM System z The Virtualization Cookbook for SLES 10 SP2, SG24-7493.

Red Hat Enterprise Linux 5 installation

Red Hat Enterprise Linux 5 was deployed on nodes lnxrh1, lnxrh2, lnxrh3, and lnxrh4 by using the following software groups:

򐂰 admin-tools

Fully qualified domain name Reverse domain name IP address

lnxsu1.itso.ibm.com 88.5.12.9.in-addr.arpa 9.12.5.88

򐂰 gnome-software-development

In addition, the following packages were added:

򐂰 device-mapper-multipath