My new Blog

Please find my articles on my new blog http://nixinfra.blogspot.com

Regards,

Siva

Network Installation Manager (NIM)

Network Installation Manager (NIM) is a IBM remote installation and management  technology similar to Linux’s Kickstart, PXE and Solaris jumpstart.

Following are the activities performed by NIM

1) New Installation (Pull method).                                                                                                   2) TL/SP upgradation.                                                                                                                     3) OS Migration/Upgradation | alt_disk_install –> cachefs method — nimadm                      4) mksysb backup/restore                                                                                                              5) Provide boot CD image for maintenance activities                                                                  6) Centralized repository for Filesets.                                                                                               7) Used to restore missed files in the mksysb backup

Apart from Installation, following are the management activities performed by NIM

1) backup                                                                                                                                            2) restore  of mksysb backupComponents of NIM.

COMPONENTS OF NIM

1) Master (NIM Master) Which will manage NIM clients for all NIM operations

2) Client (NIM Client) Systems which are managed by NIM servers for all installation, backup and restoration.

3) Resources

a) lpp_source (source of installation)                                                                                                         –> image cd/dvd                                                                                                                                –> filesets/packages                                                                                                                    –> TL/ML update This type of resource it can be used for all NIM clients.

b) SPOT (Shared Processor Object Tree)

• like a boot cd — we can boot the nimclient using SPOT It contains the “/usr” part i.e., kernel, filesets, device drivers and BOS install programs).   There are 2 types of SPOT i) lppspot ii) mksysb spot

c) mksysb specific to particular NIM client i) restoration purpose ii) customized (hardening) install of other server d) bosinst_data Customized Installation procedure (bosinst.data) (non-interactive) c) image_data image.data (rootvg architecture) — LV,VG,PP infor and arch.

4) Resource Server Server where resources are available . client can also act as RS NIM server also acts as RS.

5) NIM network Logical network which covering or connecting nim server and nim clients.

6) NIMSH (NIM service handler) For environments where the standard “rsh” protocol are not enough secure, at the time “nimsh” Using the port nos 3901 and 3902.

 

NTP Client configuration in AIX

1) Using “ntpdate” command , have a server suitable for synchronization by using the
#ntpdate -d ip.address.of.ntpserver

2) Client configuration for ntp is defined in the configuration file
#cat /etc/ntp.conf
server <NTP.SERVER.IP>
driftfile /etc/ntp.drift
tracefile /etc/ntp.trace

3) start the xntpd daemon
#startsrc -s xntpd

4) To make permanent after reboot, uncomment the following line in /etc/rc.tcpip
vi /etc/rc.tcpip
start /usr/sbin/xntpd “$src_running”

5) check the service status
# lssrc -s xntpd
Subsystem Group PID Status
xntpd tcpip 3997772 active

6) check the time sync with server
#ntpq -p

Enabling Telnet in Solaris 10

The following are the steps to enable telnet in Solaris 10

1) inetadm  -M tcp_wrappers=true
2) svcadm refresh inetd
3) inetadm -l telnet |grep tcp_wrappers
4) svcprop -p defaults inetd
5) svccfg -s inetd setprop defaults/tcp_wrappers=true
6) svcadm refresh inetd
7) inetadm -m telnet tcp_wrappers=TRUE
8) svcadm enable  telnet
9) cat /etc/hosts.allow
in.telnetd: <IP>
10) bash-3.00# cat /etc/hosts.deny
in.telnetd: ALL

Subsystem Resource Controller (SRC)

Objectives

•  Purpose of SRC
• Parts of SRC
• Commands involved in SRC

Purpose of SRC

•  A set of commands that make it very easy for the system administrators to maintain and manage the subsystems and subservers running on the system .
•   The subsystems and subservers are commonly called as “daemons”.
•   SRC allows us to stop, start, trace, list and refresh daemons.
•   SRC is started during the system initialization with a record for /usr/bin/srcmstr daemon in the /etc/inittab file

If the “srcmstr” daemon stops abnormally, the respawn action specified in /etc/inittab restarts the daemon.

Subsystem Hierarchy

Components of SRC

There are 3 important components in the SRC

Subgroup –> SubSystem –> SubServer

SubServer :
A subserver is a program or process that belongs to a subsystems, usually called daemons.
Ex: ftpd, telnetd are good examples of subservers.

SubSystem:
A “subsystem” is a program or process ( a group of program or process) that perform related functions . Subsystems can be further divided into subservers.
Ex: inetd, gated, routed, named etc.,

Subsystem Group:
A group of any specified subsystems. Grouping subsystems together allows the control of several subsystems at one time.
Ex: TCP/IP, NIS, NFS , spooler
#lssrc -g spooler
subsystem Group PID Status
qdaemon spooler 8022 active
writesrv spooler 9558 active
lpd spooler inoperative

The following derives the relationship between subsystem/subservers and subsystem group that are taken care by SRC
#lssrc -a

General Commands

1) lssrc -t
2) lssrc -s
3) lssrc -g
4) lssrc -p 4) startsrc -g
5) stopsrc -g
6) startsrc -s
7) stopsrc -s
8) startsrc -t
9) stopsrc -t
10) refresh <sg,ss,srvs>
11) mkssys –> To add subsystem
12) rmssys -s < SS> –> To remove the subsystem
13) chssys –> Change the subsystem attributes

Create your own SRC subsystem

Using  “mkssys” command to register the  your new subsystem under the control of SRC

Example:

#mkssys  -s example -p /usr/local/sample/script.sh -u $(uid -u user)  -S -n 15 -f 9 -R -Q

Flag(s)	Description
-s	Name of the new subsystem
-p	Full path to executable program / shell script.
-u	Numeric uid for subsystem execution.   Must be a defined user.
	Optional information:
-i, -o, -e	Standard input, output, error devices.     Default is /dev/console
-a	Arguments to the executable.
-G	Group name for related subsystems.
-K, -S, -I	Method of communications (Sockets [-K], Signals [-S], or Messages [-I]).     Default is Sockets.
-n, -f	The signal numbers used for normal (-n), or forced (-f), subsystem stop, if signals are used for communications.
-E	“Nice” value for subsystem execution priority.
-R, -O	Automatic restart (-R), or abort (-O) on abnormal termination. Whether to respawn or not.
-Q, -q	Single (-Q), or multiple (-q) instances allowed.
-w	Wait time between a normal and forced stop.

AIX Commands Related to Boot and Init Process

1) To find the run-level in which system is working
a) #who -r
b) cat /etc/.init.state

2) To change the runlevel from one to other
#telinit  M  or shutdown -m  –> Go to maintenance mode (single user mode)
#telinit 2

3) Shows the bootlist in normal mode & Service mode
#bootlist -m normal -o
#bootlist -m service -o

4) Sets  the bootlist in the normal mode and service mode
#bootlist -m normal hdisk1 hdisk2
#bootlist -m service cd0 hdisk1

5) To show the boot disks location code

#bootlist -m normal -ov
‘ibm,max-boot-devices’ = 0×5
NVRAM variable: (boot-device=/pci@80000002000000c/pci@2/pci1069,b166@1/scsi@0/sd@4:2)
Path name: (/pci@80000002000000c/pci@2/pci1069,b166@1/scsi@0/sd@4:4)               <–this pathname shows which blv is used
match_specific_info: ut=disk/scsi/scsd
hdisk0 blv=bos_hd5

8) To shows state of boot record
#ipl_varyon -i
 PVNAME    BOOT DEVICE         PVID                                 VOLUME GROUP ID hdisk0         YES    00183dfeba601b30000000000000000        000183df00004c00 hdisk1          NO      000183df1bc488990000000000000000        000183df00004c00

Where, hdisk0 is the boot device

9) Creates new boot record
#bosboot -ad hdisk3

10)To clears the boot record
#chpv -c hdisk3

11)  To obtain the boot device
#lslv -m hd5

12)To see the system architecture ( RS6K,P series)
#bootinfo -p

13) To see the bit addressing (32 bit or 64 bit)
#bootinfo -y

14) To check the RAM size
#bootinfo -r

15) To check the bootable disk
#bootinfo -b

16) To check the size of the hard disk
#bootinfo -s hdisk3

17) Specifies the type of boot
#bootinfo -t

18)  To shutdown the server
#shutdown
#shutdown -F  (Fast shutdown)
#halt (ungraceful shutdown)

19) Shutdown with grace period
#shutdown +3 “System is going to shutdown”

20) To reboot the server
#shutdown -Fr
#reboot or  #fastreboot ( Can be used if no users logged into the system)
Normally reboot kill the processes only, leaves the process and
communications running

21) To maintenance mode
#shutdown -m

22)  Info about boot
#who -b
#last reboot
#uptime

23) how to find where is the bootimage?
#bootinfo -v

/etc/inittab explanation

/etc/inittab file

init:2:initdefault:
brc::sysinit:/sbin/rc.boot 3 >/dev/console 2>&1 # Phase 3 of system boot
powerfail::powerfail:/etc/rc.powerfail 2>&1 | alog -tboot > /dev/console # Power Failure Detection
mkatmpvc:2:once:/usr/sbin/mkatmpvc >/dev/console 2>&1
atmsvcd:2:once:/usr/sbin/atmsvcd >/dev/console 2>&1

Inittab file lists the process that init starts, and it also specifies when to start them .

There are 4 fields in the inittab file

id   – 14 characters that identify the process. Terminals use their logical device name as an identifier
runlevel – Specified in which run level this particular process runs.
The valid run-levels could be 0-9
The default run-level in AIX is 2 multi-user mode.
Action -  How to treat the process. Possible values are
i) sysinit – processes to run the system initialization
ii) respawn – If the process is not started already, start it
iii) off – Do not run the process
iv) once – start the process and do not restart if it stops
v) wait – start the process and wait before going to the next line.

Command -  The AIX command to run to start the process.

Few Important Points on /etc/inittab

*  “telinit”  command can be used to change the run-level or to  force to re-read the /etc/inittab after any changes (telinit q)
*  The following are the commands used for inittab file configuration
i) mkitab – command to create new entry
ii) chitab – command to change the existing entry
iii) rmitab – command to remove the existing entry
iv) lsitab – command to list the entries in /etc/inittab