Cronjob run program only if other programm is already running
how do i run a cronjob only when another service is already up running and while the programm itself is not already running? It is important that programm2 starts only after programm1 is already up.
*/2 * * * * check if programm1 one is running ; check if programm2 is not running ; /etc/init.d programm2 start
cron
asked yesterday
La FleurLa Fleur
61
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add a comment |
how do i run a cronjob only when another service is already up running and while the programm itself is not already running? It is important that programm2 starts only after programm1 is already up.
*/2 * * * * check if programm1 one is running ; check if programm2 is not running ; /etc/init.d programm2 start
cron
asked yesterday
La FleurLa Fleur
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La Fleur is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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4
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday
add a comment |
how do i run a cronjob only when another service is already up running and while the programm itself is not already running? It is important that programm2 starts only after programm1 is already up.
*/2 * * * * check if programm1 one is running ; check if programm2 is not running ; /etc/init.d programm2 start
cron
asked yesterday
La FleurLa Fleur
61
New contributor
La Fleur is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
how do i run a cronjob only when another service is already up running and while the programm itself is not already running? It is important that programm2 starts only after programm1 is already up.
*/2 * * * * check if programm1 one is running ; check if programm2 is not running ; /etc/init.d programm2 start
cron
cron
asked yesterday
La FleurLa Fleur
61
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Check out our Code of Conduct.
asked yesterday
La FleurLa Fleur
61
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Check out our Code of Conduct.
asked yesterday
La FleurLa Fleur
61
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La Fleur is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked yesterday
La FleurLa Fleur
61
asked yesterday
La FleurLa Fleur
61
61
New contributor
La Fleur is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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New contributor
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4
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday
add a comment |
4
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday
4
4
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday
add a comment |
1 Answer
1
active
oldest
votes
You could write a script using the $? variable. This variable contains the exit status of the last program; so if you run systemctl status dnsmasq and it's active, running echo $? will return 0 which means true. If it's not active, $? will return a non-0 answer, which means false.
A simple script to achieve this function would be:
#/!bin/bash
x=1
while [ "$x" != "0" ]
do
systemctl status (service to monitor)
if [ "$?" = "0" ]
then
systemctl start (service to start)
break
else
sleep 30
continue
fi
done
Line 1 = sets a variable to non-zero so a loop can be run from it
Line 2 = starts a loop that runs continuously (x can never = 0)
Line 4 = checks if a service is running, which sets $? to a zero or non-zero
value
Line 5 onward = checks if the exit status of the last command (checking if the service is running) was true or false. if it's true (zero), it starts the next service and breaks out of the loop. If it's false (non-zero) it returns to the start of the loop and runs until the selected service is running.
You could either run this script at startup or turn it into a service of its own.
You would need to run it as root, whichever your choice, since you're starting/stopping system services.
answered yesterday
MintyMinty
34817
1
You are re-implementing thesystemdattributesRequires=and/orBindsTo=and/orAfter=. Also, thewhileloop will probably make the CPU fans blow because it re-runssystemctlwithout any pause.
– PerlDuck
yesterday
1
@perlduck added a 30 second sleep in theelsestatement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.
– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
add a comment |
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1 Answer
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oldest
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1 Answer
1
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oldest
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active
oldest
votes
You could write a script using the $? variable. This variable contains the exit status of the last program; so if you run systemctl status dnsmasq and it's active, running echo $? will return 0 which means true. If it's not active, $? will return a non-0 answer, which means false.
A simple script to achieve this function would be:
#/!bin/bash
x=1
while [ "$x" != "0" ]
do
systemctl status (service to monitor)
if [ "$?" = "0" ]
then
systemctl start (service to start)
break
else
sleep 30
continue
fi
done
Line 1 = sets a variable to non-zero so a loop can be run from it
Line 2 = starts a loop that runs continuously (x can never = 0)
Line 4 = checks if a service is running, which sets $? to a zero or non-zero
value
Line 5 onward = checks if the exit status of the last command (checking if the service is running) was true or false. if it's true (zero), it starts the next service and breaks out of the loop. If it's false (non-zero) it returns to the start of the loop and runs until the selected service is running.
You could either run this script at startup or turn it into a service of its own.
You would need to run it as root, whichever your choice, since you're starting/stopping system services.
answered yesterday
MintyMinty
34817
1
You are re-implementing thesystemdattributesRequires=and/orBindsTo=and/orAfter=. Also, thewhileloop will probably make the CPU fans blow because it re-runssystemctlwithout any pause.
– PerlDuck
yesterday
1
@perlduck added a 30 second sleep in theelsestatement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.
– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
add a comment |
You could write a script using the $? variable. This variable contains the exit status of the last program; so if you run systemctl status dnsmasq and it's active, running echo $? will return 0 which means true. If it's not active, $? will return a non-0 answer, which means false.
A simple script to achieve this function would be:
#/!bin/bash
x=1
while [ "$x" != "0" ]
do
systemctl status (service to monitor)
if [ "$?" = "0" ]
then
systemctl start (service to start)
break
else
sleep 30
continue
fi
done
Line 1 = sets a variable to non-zero so a loop can be run from it
Line 2 = starts a loop that runs continuously (x can never = 0)
Line 4 = checks if a service is running, which sets $? to a zero or non-zero
value
Line 5 onward = checks if the exit status of the last command (checking if the service is running) was true or false. if it's true (zero), it starts the next service and breaks out of the loop. If it's false (non-zero) it returns to the start of the loop and runs until the selected service is running.
You could either run this script at startup or turn it into a service of its own.
You would need to run it as root, whichever your choice, since you're starting/stopping system services.
answered yesterday
MintyMinty
34817
1
You are re-implementing thesystemdattributesRequires=and/orBindsTo=and/orAfter=. Also, thewhileloop will probably make the CPU fans blow because it re-runssystemctlwithout any pause.
– PerlDuck
yesterday
1
@perlduck added a 30 second sleep in theelsestatement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.
– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
add a comment |
You could write a script using the $? variable. This variable contains the exit status of the last program; so if you run systemctl status dnsmasq and it's active, running echo $? will return 0 which means true. If it's not active, $? will return a non-0 answer, which means false.
A simple script to achieve this function would be:
#/!bin/bash
x=1
while [ "$x" != "0" ]
do
systemctl status (service to monitor)
if [ "$?" = "0" ]
then
systemctl start (service to start)
break
else
sleep 30
continue
fi
done
Line 1 = sets a variable to non-zero so a loop can be run from it
Line 2 = starts a loop that runs continuously (x can never = 0)
Line 4 = checks if a service is running, which sets $? to a zero or non-zero
value
Line 5 onward = checks if the exit status of the last command (checking if the service is running) was true or false. if it's true (zero), it starts the next service and breaks out of the loop. If it's false (non-zero) it returns to the start of the loop and runs until the selected service is running.
You could either run this script at startup or turn it into a service of its own.
You would need to run it as root, whichever your choice, since you're starting/stopping system services.
answered yesterday
MintyMinty
34817
You could write a script using the $? variable. This variable contains the exit status of the last program; so if you run systemctl status dnsmasq and it's active, running echo $? will return 0 which means true. If it's not active, $? will return a non-0 answer, which means false.
A simple script to achieve this function would be:
#/!bin/bash
x=1
while [ "$x" != "0" ]
do
systemctl status (service to monitor)
if [ "$?" = "0" ]
then
systemctl start (service to start)
break
else
sleep 30
continue
fi
done
Line 1 = sets a variable to non-zero so a loop can be run from it
Line 2 = starts a loop that runs continuously (x can never = 0)
Line 4 = checks if a service is running, which sets $? to a zero or non-zero
value
Line 5 onward = checks if the exit status of the last command (checking if the service is running) was true or false. if it's true (zero), it starts the next service and breaks out of the loop. If it's false (non-zero) it returns to the start of the loop and runs until the selected service is running.
You could either run this script at startup or turn it into a service of its own.
You would need to run it as root, whichever your choice, since you're starting/stopping system services.
answered yesterday
MintyMinty
34817
edited yesterday
answered yesterday
MintyMinty
34817
answered yesterday
MintyMinty
34817
answered yesterday
MintyMinty
34817
34817
1
You are re-implementing thesystemdattributesRequires=and/orBindsTo=and/orAfter=. Also, thewhileloop will probably make the CPU fans blow because it re-runssystemctlwithout any pause.
– PerlDuck
yesterday
1
@perlduck added a 30 second sleep in theelsestatement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.
– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
add a comment |
1
You are re-implementing thesystemdattributesRequires=and/orBindsTo=and/orAfter=. Also, thewhileloop will probably make the CPU fans blow because it re-runssystemctlwithout any pause.
– PerlDuck
yesterday
1
@perlduck added a 30 second sleep in theelsestatement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.
– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
1
1
You are re-implementing the
systemd attributes Requires= and/or BindsTo= and/or After=. Also, the while loop will probably make the CPU fans blow because it re-runs systemctl without any pause.– PerlDuck
yesterday
You are re-implementing the
systemd attributes Requires= and/or BindsTo= and/or After=. Also, the while loop will probably make the CPU fans blow because it re-runs systemctl without any pause.– PerlDuck
yesterday
1
1
@perlduck added a 30 second sleep in the
else statement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.– Minty
yesterday
@perlduck added a 30 second sleep in the
else statement to address the inefficiency of running the script continuously. In regards to the former, the asker wanted a cronjob so I figured a simple script would be the most flexible solution, though not the most efficient. Thanks for the pointers.– Minty
yesterday
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
@Minty if this script is called by the cronjob mentioned by the asker, wouldn't this queue a new instance of your script every 5 minutes if the service it is waiting for is not running? If you're already using systemd, you might as well use systemd timer instead of cron and the mechanisms mentioned by PerlDuck for a pure systemd solution.
– danzel
21 hours ago
add a comment |
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4
Services that depend on other services... sounds like a task for systemd.
– danzel
yesterday