d4c0dd57f2
sources/tech/20190806 Bash Script to Automatically Start a Services When it Goes Down on Linux.md
11 KiB
Bash Script to Automatically Start a Services When it Goes Down on Linux
There are many open source monitoring tools are currently available in market to monitor Linux systems performance.
Those are send an email alert when the system reaches the specified threshold limit for CPU, Memory, and Disk space or any service is down.
But, it doesn’t have an intelligence to auto start the services, if it crash/goes down.
There are various reasons for the process to crash, which you can investigate and fix the issue but it may take a while.
If you don’t want to make your service down for a while and if you would like to bring them up immediately whenever it goes down?
If so, what to do in this situation? How to mitigate this?
We can write our own bash script to start a service whenever it goes down. Writing a shell script is not a big deal and you have to understand few things to achieve this.
Once you familiar on this, you can write your own shell script to automate the day to day activities, which will save lots of time.
We had added many useful shell scripts in the past. If you want to check those, navigate to the below link.
I have added totally six shell scripts for this usage and you can choose which one is suitable for you.
I had applied different commands and methodology in each shell script.
Note: You need to change the email id instead of ours.
1) How to Automatically Start a Service When it Goes Down on SysVinit Linux System?
Use the following bash script, if you would like to start a single service in SysVinit Linux System.
I have added httpd service in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor.sh
#!/bin/bash
serv=httpd
sstat=stopped
service $serv status | grep -i 'running\|stopped' | awk '{print $3}' | while read output;
do
echo $output
if [ "$output" == "$sstat" ]; then
service $serv start
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
echo "$serv service is running"
fi
done
Set an executable permission to service-monitor.sh file.
$ chmod +x /opt/scripts/service-monitor.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor.sh
Alternatively, you can use the following script.
# vi /opt/scripts/service-monitor-1.sh
#!/bin/bash
serv=httpd
sstat=$(pidof $serv | wc -l )
if [ $sstat -gt 0 ]
then
echo "$serv is running fine!!!"
else
echo "$serv is down/dead"
service $serv start
echo "$serv service is UP now!!!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
Set an executable permission to service-monitor-1.sh file.
$ chmod +x /opt/scripts/service-monitor-1.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-1.sh
2) How to Automatically Start a Service When it Goes Down on systemd Linux System?
Use the following bash script, if you would like to start a single service in systemd Linux System.
I have added httpd service in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor-2.sh
#!/bin/bash
serv=httpd
sstat=dead
systemctl status $serv | grep -i 'running\|dead' | awk '{print $3}' | sed 's/[()]//g' | while read output;
do
echo $output
if [ "$output" == "$sstat" ]; then
systemctl start $serv
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
echo "$serv service is running"
fi
done
Set an executable permission to service-monitor-2.sh file.
$ chmod +x /opt/scripts/service-monitor-2.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-2.sh
Alternatively, you can use the following script.
# vi /opt/scripts/service-monitor-3.sh
#!/bin/bash
serv=httpd
sstat=$(pidof $serv | wc -l )
if [ $sstat -gt 0 ]
then
echo "$serv is running fine!!!"
else
echo "$serv is down/dead"
systemctl start $serv
echo "$serv service is UP now!!!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
Set an executable permission to service-monitor-3.sh file.
$ chmod +x /opt/scripts/service-monitor-3.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-3.sh
3) How to Automatically Start Multiple Services When it Goes Down on SysVinit Linux System?
Use the following bash script, if you would like to start multiple service in SysVinit Linux System.
I have added httpd and rsyslog services in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor-4.sh
#!/bin/bash
sstat=stopped
for serv in httpd rsyslog
do
service $serv status | grep -i 'running\|stopped' | awk '{print $3}' | while read output;
do
echo $output
if [ "$output" == "$sstat" ]; then
service $serv start
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
echo "$serv service is running"
fi
done
done
Set an executable permission to service-monitor-4.sh file.
$ chmod +x /opt/scripts/service-monitor-4.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-4.sh
Alternatively, you can use the following script.
# vi /opt/scripts/service-monitor-5.sh
#!/bin/bash
for serv in rsyslog httpd
do
sstat=$(pgrep $serv | wc -l )
if [ $sstat -gt 0 ]
then
echo "$serv is running!!!"
else
echo "$serv is down/dead"
service $serv start
echo "$serv serv is UP now!!!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
done
Set an executable permission to service-monitor-5.sh file.
$ chmod +x /opt/scripts/service-monitor-5.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-5.sh
4) How to Automatically Start Multiple Service When it Goes Down on systemd Linux System?
Use the following bash script, if you would like to start multiple services in systemd Linux System.
I have added httpd and rsyslog services in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor-6.sh
#!/bin/bash
sstat=dead
for serv in httpd rsyslog
do
systemctl status $serv | grep -i 'running\|dead' | awk '{print $3}' | sed 's/[()]//g' | while read output;
do
echo $output
if [ "$output" == "$sstat" ]; then
systemctl start $serv
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
echo "$serv service is running"
fi
done
done
Set an executable permission to service-monitor-6.sh file.
$ chmod +x /opt/scripts/service-monitor-6.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-6.sh
Alternatively, you can use the following script.
# vi /opt/scripts/service-monitor-7.sh
#!/bin/bash
for serv in rsyslog httpd
do
sstat=$(pgrep $serv | wc -l )
if [ $sstat -gt 0 ]
then
echo "$serv is running!!!"
else
echo "$serv is down/dead"
systemctl start $serv
echo "$serv serv is UP now!!!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
done
Set an executable permission to service-monitor-7.sh file.
$ chmod +x /opt/scripts/service-monitor-7.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-7.sh
5) How to Automatically Start a Service When it Goes Down on systemd and SysVinit Linux System?
Use the following bash script, if you would like to start a service in systemd and SysVinit Linux System.
I have added httpd service in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor-8.sh
#!/bin/bash
smanager=$(ps -p1 | grep "init\|systemd" | awk '{print $4}')
serv=httpd
if (( $(pidof $serv | wc -l) > 0 ))
then
echo "$serv is running!!!"
elif [ "$smanager" == "init" ]
then
service $serv start
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
systemctl start $serv
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
Set an executable permission to service-monitor-8.sh file.
$ chmod +x /opt/scripts/service-monitor-8.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-8.sh
6) How to Automatically Start Multiple Services When it Goes Down on systemd and SysVinit Linux System?
Use the following bash script, if you would like to start multiple services in systemd and SysVinit Linux System.
I have added httpd and rsyslog services in this script but you can add the service, which you want to monitor.
# vi /opt/scripts/service-monitor-9.sh
#!/bin/bash
smanager=$(ps -p1 | grep "init\|systemd" | awk '{print $4}')
for serv in rsyslog httpd
do
if (( $(pgrep $serv | wc -l) > 0 ))
then
echo "$serv is running!!!"
elif [ "$smanager" == "init" ]
then
service $serv start
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
else
systemctl start $serv
echo "$serv service is UP now.!" | mail -s "$serv service is DOWN and restarted now On $(hostname)" [email protected]
fi
done
Set an executable permission to service-monitor-9.sh file.
$ chmod +x /opt/scripts/service-monitor-9.sh
Finally add a cronjob to automate this. It will run every 5 minutes.
# crontab -e
*/5 * * * * /bin/bash /opt/scripts/service-monitor-9.sh
via: https://www.2daygeek.com/linux-bash-script-auto-restart-services-when-down/
作者：Magesh Maruthamuthu 选题：lujun9972 译者：译者ID 校对：校对者ID