Fri. Jul 10th, 2020

Service control and runlevel in Linux

1 min read

How to control the running status of the service?

Service Control

ntsysv

ntsysv is a simple interface for configuring runlevel services which are also configurable through chkconfig. To start the utility, type ntsysv at a shell prompt as root.

At the same time, to manage the services in the specified run level, not only the services in the current run level:

ntsysv –level 35

systemctl

systemctl is a controlling interface and inspection tool for the widely-adopted init system and service manager systemd.

  • systemctl {option} name.servive

start: Start the service
stop: Stop the service

restart: Restart, stop first, then start the service
reload: reload the configuration file without completely stopping and starting the service

status: Status the service
is-active: Whether the startup was successful
is-failed: Whether the startup failed

enable: Auto-startup
disable: Turn off auto-startup
is-enabled: Whether to auto-startup

list-dependencies: View dependencies

mask: Block service
unmask: Unblock service

Example: systemctl start httpd.service

runlevel

A runlevel is a mode of operation in the computer operating systems that implement Unix System V-style initialization. Conventionally, seven runlevels exist, numbered from zero to six. S is sometimes used as a synonym for one of the levels. Only one runlevel is executed on startup; run levels are not executed one after another (i.e. only runlevel 2, 3, or 4 is executed, not more of them sequentially or in any other order).

runlevel

  • Display the operating level of the system: runlevel

Switch multi-user mode

init 5

or

systemctl isolate multi-user.target