The System Resource Controller (SRC) provides a set of commands and subroutines to make it easier for the system admins/users to create and control subsystems.
What is Subsystem?
A subsystem is any program or process or set of programs or processes that is usually capable of operating independently or with a controlling system.A subsystem is designed as a unit to provide a designated function.
Features of System Resource Controller (SRC):
- Subsystem is a set of related programs designed to perform one particular function.
- The subsystems can be sub divided into subservers(daemons).
- SRC helps you to manage the whole subsystems and their respective subservers by creating subsystem groups.
- SRC allows us to stop, start, trace, list and refresh subsystems and subservers (daemons).
- SRC is started during the system initialization with a record for /usr/bin/srcmstr daemon in the /etc/inittab file.
There are three basic components of SRC
Subgroup –> SubSystem –> SubServer (daemons)
Subserver
A subserver is a program or process that belongs to a subsystem called as deamons as well.
Eg: sshd,ftpd
Subsystem
A subsystem can have multiple subservers and is responsible for starting, stopping, and providing status of subservers.
Eg: gated,inetd,named etc.,
Subsystem Group
A subsystem group is a group of any specified subsystems. Grouping subsystems together allows the control of several subsystems at one time.
Eg: TCP/IP, Network Information System (NIS), and Network File Systems (NFS).
In the above example
Subsystem group "tcp/ip" under which there is subsystem "inetd" under which there is a subserver called "ftp" here.
Subsystem Operational Commands:
| Item | Description |
|---|---|
| srcmstr | Deamon starts the System Resource Controller |
| startsrc | Starts a subsystem, subsystem group, or subserver |
| stopsrc | Stops a subsystem, subsystem group, or subserver |
| refresh | Refreshes a subsystem |
| traceson | Turns on tracing of a subsystem, a group of subsystems, or a subserver |
| tracesoff | Turns off tracing of a subsystem, a group of subsystems, or a subserver |
| lssrc | Gets status on a subsystem. |
| Command | Description |
|---|---|
| lssrc -a | To list the status of all subsystems |
| lssrc -h node1-a | To list the status of all subsystems on foreign host node1 |
| lssrc -s inetd | To list the status of the subsystem inetd |
| lssrc -g tcpip | To get the status of the subsystem group tcpip |
| startsrc -s inetd | To start the subsystem inetd |
| startsrc -g tcpip | To start the subsystem group tcpip |
| stopsrc -s inetd | To stop the subsystem inetd (If process is under srcmstr. ie PPID of process=PID of srcmstr) |
| stopsrc -g tcpip | To stop the subsystem group tcpip |
| refresh -s nfsd | To refresh nfsd subsystem |
| refresh -g tcpip | To refresh tcpip subsystem group |
| lssrc -p [PID of process] | To get status of the subsystem by process ID |
| kill [PID of process] | To kill a process that not started by srcmstr |
mkssy ==> Create Subsystem
chssys ==> Chnage or modify Subsystem Parameters
rmssys ==> Remove Subsystem
# mkssys -p /usr/sbin/sshd \ /* Absolute path to the subsystem executable
program. */
-s sshd_adm \ /* Name that uniquely identifies the subsys. */
-u 0 \ /* User id for the subsystem. */
-a "-D -f /etc/ssh/sshd_config_adm" \ /* Arguments that must be
passed to the command. */
-e /dev/console \ /* Where the subsystem standard error data is
placed. */
-i /dev/console \ /* Where the subsys. standard input is routed. */
-o /dev/console \ /* Where the subsys. standard output is placed. */
-R \ /* Subsystem is restarted if the subsystem stops
abnormally. */
-Q \ /* Multiple instances of the subsystem are not
allowed to run at the same time. */
-S \ /* Subsystem uses the signals communication
method. */
-f 9 \ /* Signal sent to the subsystem when a forced
stop of the subsystem is requested. */
-n 15 \ /* Signal sent to the subsystem when a normal
stop of the subsystem is requested. */
-E 20 \ /* Execution priority of the subsystem. */
-G ssh \ /* Subsystem belongs to the group specified. */
-d \ /* Inactive subsystems are displayed when the
lssrc -a command request is made. */
-w 20 /* Time, in seconds, allowed to elapse between a
stop cancel (SIGTERM) signal and a subsequent
SIGKILL signal. */
Check the service's configuration:
# lssrc -S -s sshd_adm
#subsysname:synonym:cmdargs:path:uid:auditid:standin:standout:standerr:action:multi:contact:svrkey:svrmtype:\
priority:signorm:sigforce:display:waittime:grpname:
sshd_adm::-D -f /etc/ssh/sshd_config_adm:/usr/sbin/sshd:0:0:/dev/console:/dev/console:/dev/console:-R:-Q:-S:0:0:\
20:15:9:-d:20:ssh:
# odmget -q subsysname=sshd_adm SRCsubsys
SRCsubsys:
subsysname = "sshd_adm"
synonym = ""
cmdargs = "-D -f /etc/ssh/sshd_config_adm"
path = "/usr/sbin/sshd"
uid = 0
auditid = 0
standin = "/dev/console"
standout = "/dev/console"
standerr = "/dev/console"
action = 1
multi = 0
contact = 2
svrkey = 0
svrmtype = 0
priority = 20
signorm = 15
sigforce = 9
display = 1
waittime = 20
grpname = "ssh"
program. */
-s sshd_adm \ /* Name that uniquely identifies the subsys. */
-u 0 \ /* User id for the subsystem. */
-a "-D -f /etc/ssh/sshd_config_adm" \ /* Arguments that must be
passed to the command. */
-e /dev/console \ /* Where the subsystem standard error data is
placed. */
-i /dev/console \ /* Where the subsys. standard input is routed. */
-o /dev/console \ /* Where the subsys. standard output is placed. */
-R \ /* Subsystem is restarted if the subsystem stops
abnormally. */
-Q \ /* Multiple instances of the subsystem are not
allowed to run at the same time. */
-S \ /* Subsystem uses the signals communication
method. */
-f 9 \ /* Signal sent to the subsystem when a forced
stop of the subsystem is requested. */
-n 15 \ /* Signal sent to the subsystem when a normal
stop of the subsystem is requested. */
-E 20 \ /* Execution priority of the subsystem. */
-G ssh \ /* Subsystem belongs to the group specified. */
-d \ /* Inactive subsystems are displayed when the
lssrc -a command request is made. */
-w 20 /* Time, in seconds, allowed to elapse between a
stop cancel (SIGTERM) signal and a subsequent
SIGKILL signal. */
Check the service's configuration:
# lssrc -S -s sshd_adm
#subsysname:synonym:cmdargs:path:uid:auditid:standin:standout:standerr:action:multi:contact:svrkey:svrmtype:\
priority:signorm:sigforce:display:waittime:grpname:
sshd_adm::-D -f /etc/ssh/sshd_config_adm:/usr/sbin/sshd:0:0:/dev/console:/dev/console:/dev/console:-R:-Q:-S:0:0:\
20:15:9:-d:20:ssh:
# odmget -q subsysname=sshd_adm SRCsubsys
SRCsubsys:
subsysname = "sshd_adm"
synonym = ""
cmdargs = "-D -f /etc/ssh/sshd_config_adm"
path = "/usr/sbin/sshd"
uid = 0
auditid = 0
standin = "/dev/console"
standout = "/dev/console"
standerr = "/dev/console"
action = 1
multi = 0
contact = 2
svrkey = 0
svrmtype = 0
priority = 20
signorm = 15
sigforce = 9
display = 1
waittime = 20
grpname = "ssh"
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