upstart

Question 1

start and stop services in an asynchronous manner which also decreased the boot up time fora Linux system. This benefit came about
by Upstarts ability to start services in parallel of one another, rather than waiting on one service to start before it could start up the next one.
This flow is the main way that Upstart starts a system. And it may look just as sequential as the old Init system.
However, after the start-up event begins there are multiple other jobs that are running at the same time that we don’t have listed here.

hardly any Linux distributions use it anymore. The focus of looking at Upstart is to demonstrate a type of initialization daemon that made a leap from being a static startup
or shutdown mechanism to one that actually kept track of what was going on with the system and reacting to it.

Answer 1

Upstart Init daemon

Question 2

real time events

Answer 2

advantage of upstart over init

Question 3

upstart monitors the services that it works with If a service stops working unexpectedly Upstart
will make attempts to get it running again.

Answer 3

monitoring

Question 4

fire off the startup event
mountall
startup also runs the /etc/init/rc-sysinit.conf script
rc-sysinit.conf script
telinit
runlevel
/etc/init/rc.conf
login

Answer 4

upstart boot sequence

Question 5

that will check and mount the drives that make up the file system using the mountall tool.

Answer 5

The startup event

Question 6

checks to see if there is an /etc/init tab file to see if there are any configuration options set there.

Answer 6

/etc/init/rc-sysinit.conf script

Question 7

calls telinit to switch into the default run level via the runlevel command.

Answer 7

rc-sysinit.conf script

Question 8

start off many other jobs from Upstart to get the system ready and provides a compatibility mechanism to legacy scripts that may require specific run levels.

Answer 8

run level command for upstart not the same as init

Question 9

When something on a Linux system changes and when an event is triggered it starts an Upstart
job that is then further divided into task and services.

Answer 9

event

Question 10

By executing the joband passing the expected run level, as an argument.

Answer 10

/etc/init/rc.conf

Question 11

what is requested of it and then return to a waiting state once it has finished. A service will not typically stop by itself.
The Upstart daemon will monitor each service and it will only kill a service if an event calls for it or if an administrator manually stops it.

Answer 11

task

Question 12

condition at a point in time on the system.

Answer 12

job state

Question 13

waiting state

Answer 13

initial state of a job. It isn’t doing anything yet but is just waiting to do something.

Question 14

that the job itself is about to start.

Answer 14

starting state

Question 15

means that the job is running.

Answer 15

running state

Question 16

The is an interim state where the job has processed a section of its configuration known as prestop.
The job is not actually stopping at this point.

Answer 16

stopping state

Question 17

is where the job is actually stopping.

Answer 17

killed state

Question 18

the job has completely stopped and once it is done here it goes back into the waiting state.

Answer 18

post-stop state

Question 19

occurs when something goes wrong with it while a job is running and it quits unexpectedly and Upstart will attempt to
respond the job up to 10 times at 5 second intervals before the job is dropped entirely.

Answer 19

Respawning