System information
Sharing and maintaining SLES 10 SP2 Linux under z/VM 5
A more detailed summary of these systems is in section 1.4, “Summary of virtual machines”
on page 19.
1.3.3 High level approach of read-only root system
In the section that follows, the read-only root solution is described at a high level. In addition
to the read-only root environment, a maintenance process is also established. Details on
implementing the solution begin in section 1.5, “Building a read-write maintenance system”
on page 20.
SLES 10 SP2 Linux is installed on an initial virtual server with the z/VM user ID
S10RWMNT(Figure 1-2). Packages to create a minimal Linux system are selected, security
hardening done and other configuration changes are applied. This server has the minidisks
described in Table 1-1 on page 16.
Figure 1-2 Installing the first Linux system
Once Linux is installed onto the initial server (S10RWMNT), it is shutdown and copied to a test
server, S10RWTST (see
Figure 1-3). Linux is configured on this user ID where all features and
functions are tested and validated. When the system is validated, it is copied in the reverse
direction (note that the IP address and host name are not changed, therefore, only one user
ID can have Linux running at any time). If changes on the test system are not valid, they can
be discarded by recopying the maintenance system.
Figure 1-3 Cloning the first Linux system
Once configuration and testing are completed, the read-write Linux system is frozen to
become the source disks for Linux cloning. This copy is called the gold version of the Linux
minidisks.This whole system is shown in Figure 1-4. A Linux script (cloneprep.sh) is written
to clean up the system before cloning. After running the cleanup script, the system is
shutdown, then the disks are copied to the gold user ID by means of a REXX EXEC.
At Nationwide, there are three versions of the gold minidisks maintained: old, current, and
next. This paper only addresses a single copy: current. To add additional versions such as
S10RWMNT
I
n
s
t
a
l
l
m
e
d
i
a
S10RWMNT
S10RWTST
I
n
s
t
a
l
l
m
e
d
i
a
CMSCLONE
t
s
t
2
m
n
t
e
x
e
c
m
n
t
2
t
s
t
e
x
e
c