| Startup and shutdown scripts for HP-UX 11.x are based on a mechanism that separates the actual startup and shutdown scripts from configuration information. In order to modify the way your system starts or stops, you don't have to modify scripts, which in general is considered somewhat risky; you can, instead, modify configuration variables. The startup and shutdown sequence is based on an industry standard that is similar to many other UNIX-based systems, so your knowledge of HP-UX applies to many other systems. Startup and shutdown are going to become increasingly more important to you as your system administration work becomes more sophisticated. As you load and customize more applications, you will need more startup and shutdown knowledge. What I do in this section is give you an overview of startup and shutdown and the commands you can use to control your system. The following components are in the startup and shutdown model: | Execution Scripts | Execution scripts read variables from configuration variable files and run through the startup or shutdown sequence. These scripts are located in /sbin/init.d. | | Configuration Variable Scripts | These are the files you would modify to set variables that are used to enable or disable a subsystem or perform some other function at the time of system startup or shutdown. These are located in /etc/rc.config.d. | | Link Files | These files are used to control the order in which scripts execute. These are actually links to execution scripts to be executed when moving from one run level to another. These files are located in the directory for the appropriate run level, such as /sbin/rc0.d for run level 0, /sbin/rc1.d for run level 1, and so on. | | Sequencer Script | This script invokes execution scripts based on run-level transition. This script is located in / sbin/rc. |
Figure 8-1 shows the directory structure for startup and shutdown scripts. Figure 8-1. Organization of Startup and Shutdown Files Execution scripts perform startup and shutdown tasks. /sbin/rc invokes the execution script with the appropriate start or stop arguments, and you can view the appropriate start or stop messages on the console. The messages you see will have one of the three following values: | OK | This indicates that the execution script started or shut down properly. | | FAIL | A problem occurred at startup or shutdown. | | N/A | The script was not configured to start. |
In order to start up a subsystem, you would simply edit the appropriate configuration file in /etc/rc.config.d. Let's take a look at an example startup and shutdown file for an application loaded onto an HP-UX system that is widely used for Internet applications called Cold Fusion. Like many applications loaded on HP-UX systems, Cold Fusion installs startup and shutdown scripts as a standard part of the installation of the product. As mentioned earlier, the script used as part of the startup and shutdown process is in /etc/init.d. In our case, the name of the program is /etc/ init.d/coldfusion and is shown in the following listing: # cat /sbin/init.d/coldfusion #!/bin/sh # # Start the Cold Fusion servers # # set at install CFHOME=/apps/coldfusion CFBIN=$CFHOME/bin export CFHOME # # Start/stop processes for Cold Fusion # rval=0 case "$1" in start_msg) print "Starting ColdFusion Application Server" ;; stop_msg) print "Stopping ColdFusion Application Server" ;; 'start') #First, check "on/off switch", to set CF_AUTOSTART, in config.d file. RCFILE=/etc/rc.config.d/coldfusion if [ -f $RCFILE ] ; then . $RCFILE else print "Warning: $RCFILE defaults file missing." print " Starting ColdFusion by default." CF_AUTOSTART=1 fi # Start CF if switch is on. if [ "$CF_AUTOSTART" -eq 1 ]; then if [ -x $CFBIN/start ]; then $CFBIN/start rval=$? else print "Error: ColdFusion startup script $CFBIN/start missing." print " ColdFusion not started." rval=1 fi else print "Notice: ColdFusion startup disabled in $RCFILE" rval=2 fi ;; 'stop') if [ -x $CFBIN/stop ]; then $CFBIN/stop -force fi ;; *) echo "Usage: $0 { start | stop }" rval=1 ;; esac exit $rval # The startup and shutdown scripts in /etc/init.d generally perform both startup and shutdown functions. The startup and shutdown scripts, including the one in our example, recognize the following four arguments: start_msg - This is an argument passed to scripts so that the script can report a message indicating what the "start" action will do. stop_msg - This is an argument passed to scripts so that the script can report a message indicating what the "stop" action will do. start - The script will start the application. stop - The script will shut down the application.
All startup and shutdown scripts, including the one in the preceding listing, obtain configuration data from variables in /etc/rc.config.d.Our example script checks the value of the "on/off" switch in /etc/rc.confi.d/ coldfusion, which is shown in the following listing to determine if Cold Fusion should be started: # cat /etc/rc.config.d/coldfusion # ColdFusion Application Server configuration file # CF_AUTOSTART=1 #Set to 1 to restart at boot time # The variable in this file is set to one, so the application will start at the time of system boot. Startup and shutdown scripts are run based on the directory in which a link to the script appears. Our example script should be started at run level three. Therefore, a link to the script appears in the directory /sbin/rc3.d, shown as the third link in the following listing: # ls -l /sbin/rc3.d total 0 lrwxr-xr-x 1 root sys 23 Apr 26 14:32 S100nfs.server -> /sbin/init.d/nfs.server lrwxr-xr-x 1 root sys 19 Apr 26 14:52 S200tps.rc -> /sbin/init.d/tps.rc lrwxrwxrwx 1 root sys 20 May 16 20:57 S790coldfusion -> ../init.d/coldfusion lrwxr-xr-x 1 root sys 23 Apr 26 14:44 S990dtlogin.rc -> /sbin/init.d/dtlogin.rc # We'll get to the significance of the naming of the link shortly. For the time being, it is sufficient to know that a link called /sbin/rc3.d/ S790coldfusion points to our script /init.d/coldfusion. Applications are shut down in the opposite order from which they were started. This means that a link to the startup and shutdown script will appear in a lower-level directory for shutdown. In our example, the startup link appears in /sbin/rc3.d but the shutdown link appears in /etc/rc1.d, as shown in the following listing: # ls -l /sbin/rc1.d lrwxr-xr-x 1 root sys 17 Apr 26 14:52 K220slsd -> /sbin/init.d/slsd lrwxr-xr-x 1 root sys 18 Apr 26 14:45 K230audio -> /sbin/init.d/audio lrwxr-xr-x 1 root sys 21 Apr 26 14:46 K240auditing -> /sbin/init.d/auditing lrwxr-xr-x 1 root sys 17 Apr 26 14:43 K250envd -> /sbin/init.d/envd lrwxr-xr-x 1 root sys 17 Apr 26 14:43 K270cron -> /sbin/init.d/cron lrwxr-xr-x 1 root sys 15 Apr 26 14:45 K278pd -> /sbin/init.d/pd lrwxr-xr-x 1 root sys 15 Apr 26 14:45 K280lp -> /sbin/init.d/lp lrwxr-xr-x 1 root sys 21 Apr 26 14:49 K290hparamgr -> /sbin/init.d/hparamgr lrwxr-xr-x 1 root sys 20 Apr 26 14:43 K290hparray -> /sbin/init.d/hparray lrwxrwxrwx 1 root sys 20 May 16 20:57 K300coldfusion -> ../init.d/coldfusion . . . The link called /sbin/rc3.d/K300coldfusion points to our script /init.d/ coldfusion. Startup for this application takes place at run level 3, and shutdown takes place at run level 1. There is significance associated with the names of the links shown in the preceding two listings. Let's take a look at the startup link in our example: /sbin/rc3.d/S790coldfusion | | | | | | | v | | | script name - coldfusion in example | | v | | sequence number - 790 in example | v | "S" for startup, "K" for shutdown v run level number - 3 in example This example is for our Cold Fusion startup script. Startup links begin with an "S" for startup. The shutdown script has a similar entry in /sbin/ rc1.d, but it has a "K" as the first character of the link name to indicate kill. Scripts are executed in lexicographical order. Gaps are left between startup scripts at a given run level and between shutdown scripts at a given run level, so when additional scripts are added, you don't have to renumber any existing scripts within a run level. Because applications are shut down in the opposite order in which they are started, shutdown scripts do not usually have the same numbers as their startup counterparts. Two applications that start in a given order due to dependencies will usually be shut down in the opposite order in which they were started. In our example, the startup number is S790coldfusion and the shutdown number is K300coldfusion. Scripts are run when there is a change in run level. /sbin/rc is a program that is run whenever there is a change in run level. The following listing shows /etc/inittab, which invokes /sbin/rc on the system used in our example: init:3:initdefault: ioin::sysinit:/sbin/ioinitrc >/dev/console 2>&1 tape::sysinit:/sbin/mtinit > /dev/console 2>&1 muxi::sysinit:/sbin/dasetup </dev/console >/dev/console 2>&1 # mux init stty::sysinit:/sbin/stty 9600 clocal icanon echo opost onlcr ixon icrnl ignpar </dev/ systty brc1::bootwait:/sbin/bcheckrc </dev/console >/dev/console 2>&1 # fsck, etc. link::wait:/sbin/sh -c "/sbin/rm -f /dev/syscon; \ /sbin/ln /dev/systty /dev/syscon" >/dev/console 2>&1 cprt::bootwait:/sbin/cat /etc/copyright >/dev/syscon # legal req sqnc::wait:/sbin/rc </dev/console >/dev/console 2>&1 # system init #powf::powerwait:/sbin/powerfail >/dev/console 2>&1 # powerfail cons:123456:respawn:/usr/sbin/getty console console # system console #ttp1:234:respawn:/usr/sbin/getty -h tty0p1 9600 #ttp2:234:respawn:/usr/sbin/getty -h tty0p2 9600 #ttp3:234:respawn:/usr/sbin/getty -h tty0p3 9600 #ttp4:234:respawn:/usr/sbin/getty -h tty0p4 9600 #ttp5:234:respawn:/usr/sbin/getty -h tty0p5 9600 #ups::respawn:rtprio 0 /usr/lbin/ups_mond -f /etc/ups_conf The /sbin/rc line is always present in the /etc/inittab file. There is more information about /etc/inittab coming shortly. If you are booting your system to run level 3, then /sbin/rc will run the startup scripts present in /sbin/rc1.d, /sbin/rc2.d, and /sbin/rc3.d. I have mentioned run levels several times in this discussion. Both the startup and shutdown scripts described here, as well as the /etc/inittab file, depend on run levels. In HP-UX 11.x, the following run levels exist: | 0 | Halted run level. | | s | Run level s, also known as single-user mode, is used to ensure that no one else is on the system so you can proceed with system administration tasks. | | 1 | Run level 1 starts various basic processes. | | 2 | Run level 2 allows users to access the system. This is also known as multi-user mode. | | 3 | Run level 3 is for exporting NFS file systems. | | 4 | Run level 4 starts the graphical manager, including HP Common Desktop Environment (HP CDE). | | 5 and 6 | Not currently used. |
/etc/inittab is also used to define a variety of processes that will be run, and it is used by /sbin/init. The /sbin/init process ID is 1. It is the first process started on your system and it has no parent. The init process looks at / etc/inittab to determine the run level of the system. Entries in the /etc/inittab file have the following format: id:run state:action:process | id | The name of the entry. The id is up to four characters long and must be unique in the file. If the line in /etc/inittab is preceded by a "#", the entry is treated as a comment. | | run state | Specifies the run level at which the command is executed. More than one run level can be specified. The command is executed for every run level specified. | | action | Defines which of 11 actions will be taken with this process. The 11 choices for action are: initdefault, sysinit, boot, bootwait, wait, respawn, once, powerfail, powerwait, ondemand, and off. | | process | The shell command to be executed if the run level and/or action field so indicates. |
Here is an example of an /etc/inittab entry: This is in the /etc/inittab file, as opposed to being defined as a startup script, because the console may be killed and have to be restarted whenever it dies, even if no change has occurred in run level. respawn starts a process if it does not exist and restarts the process after it dies. This entry shows all run states, since you want the console to be activated at all times. Another example is the first line from /etc/inittab: init:3:initdefault: The default run level of the system is defined as 3. The basics of system startup and shutdown described here are important to understand. You will be starting up and shutting down your system and possibly even modifying some of the files described here. Please take a close look at the startup and shutdown files before you begin to modify them. Now let's take a look at the commands you can issue to shut down your system. System Shutdown What does it mean to shut down the system? Well, in its simplest form, a shutdown of the system simply means issuing the /sbin/shutdown command. The shutdown command is used to terminate all processing. It has many options, including the following: | -r | Automatically reboots the system; that is, brings it down and brings it up. | | -h | Halts the system completely. | | -y | Completes the shutdown without asking you any questions that it would normally ask. | | grace | Specifies the number of seconds you wish to wait before the system is shut down, in order to give your users time to save files, quit applications, and log out. |
Here are some of the things your system does when you issue the shutdown command: Checks to see whether the user who executed shutdown does indeed have permission to execute the command. Changes the working directory to root (/). Sets PATH to /usr/bin/:/usr/sbin:/sbin. Updates all superblocks. Informs users that a shutdown has been issued and asks them to log out. Executes /sbin/rc, which does such things as shut down subsystems via shutdown scripts such as the spooler and CDE, unmount file systems and other such tasks. Runs/sbin/reboot if the -r option is used.
To shut down and automatically reboot the system, you would type: $ shutdown -r To halt the system, you would type: $ shutdown -h You will be asked whether you want to type a message to users, informing them of the impending system shutdown. After you type the message, it is immediately sent to all users. After the specified time elapses (60 seconds is the default), the system begins the shutdown process. Once you receive a message that the system is halted, you can power off all your system components. To shut down the system in two minutes without being asked any questions or sending any message, type: $ shutdown -h -y 120 At times, you will need to go into single-user mode with shutdown to perform some task such as a backup or to expand a logical volume, and then reboot the system to return it to its original state. To shut down the system into single-user mode, you would type: $ shutdown The shutdown command with no options puts you into single-user mode. On older versions of the operating system, you could go to single-user mode by using the init command with the s option (init s). However, this is highly discouraged because this command does not terminate other system activity nor does it log users off; therefore, it does not result in a true single-user state. If the system is already in single-user mode or you like to live dangerously, you can execute /usr/sbin/reboot. I strongly suggest that you issue shutdown, which will call reboot. The reboot command abruptly terminates all processes and then halts or reboots the system. Also, with dynamically loadable kernel modules, reboot will not load these modules; only shutdown will. Again, I recommend using the shutdown command, not reboot. |