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Status
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titleLAST TESTED ON CHECKMK 2.23.0P1


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titleTable of Contents

Table of Contents

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You may be impacted by a Cannot Create Graph error:

Screenshot of CPU utilization service for mysite01. Error reads cannot create graphImage RemovedImage Added


To visualize a graph, Checkmk uses RRD. The RRD needs, by nature, two files:, stored in ~/var/check_mk/rrd/HOSTNAME

Code Block
languagebash
themeRDark
-rw-rw------ 1 mysite mysite 65 Oct    93 Jun  2 07:219 13:34 CPU_Utilization_Packet_CPU_2utilization.info
-rw-r--r-- 1 mysite mysite 1534768 384952Oct Jun  2 11:2230 09:00 CPU_Utilization_Packet_CPU_2utilization.rrd


The .rrd file stores all the data, and the .info file defines the service metrics. You will face the message above if one of the files is missing. This message will also be displayed in the cmc.log:

Code Block
languagebash
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OMD[mysite]:~$ tail ~$ tail -f var/log/cmc.log
20222024-0610-0230 1209:0902:4155 [4] [main]client [rrd0] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: Error accessing RRD: opening '/opt/omd/sites/mysite/var/check_mk/rrd/myhostlinux/CPU_Utilization_Packet_CPU_1.rrd
2022-06-02 12:10:41utilization.rrd': No such file or directory
2024-10-30 09:02:55 [4] [main]client [rrd0] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: Error accessing RRD: opening '/opt/omd/sites/mysite/var/check_mk/rrd/myhostlinux/CPU_Utilization_Mgmt_CPUTCP_Connections.rrd
2022-06-02 12:10:41': No such file or directory
2024-10-30 09:02:55 [4] [main]client [rrd0] [rrdcached at /omd/sites/mysite/tmp/run/rrdcached.sock] >> -1 No such file: Error accessing RRD: opening '/opt/omd/sites/mysite/var/check_mk/rrd/myhostlinux/CPUSystemd_Utilization_Packet_CPU_0.rrdTimesyncd_Time.rrd': No such file or directory

Solution

Unfortunately, for some reason, one of the files is missing. In that case, it is the .rrd file. So to make the graphs work again, you need to  stop the site, to do the following:

Stop the site:

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OMD[mysite]:~$ omd stop

Run the below oneliner to find all the .info files with that have a missing .rrd file, and delete them manually: :

Note

The below oneliner will not delete anything, it only lists the missing files.


Code Block
languagebash
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OMD[mysite]:~$ for i in $(find ~/var/check_mk/rrd -name "*.info"); do test -e "${i%info}rrd" || echo "$i"; done

The output is the following:

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languagebash
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/omd/sites/mysite/var/check_mk/rrd/myhostlinux/PINGCPU_utilization.info
/omd/sites/mysite/var/check_mk/rrd/myhostlinux/CPU_Utilization_Mgmt_CPUTCP_Connections.info
/omd/sites/mysite/var/check_mk/rrd/myhostlinux/CPUSystemd_Utilization_Packet_CPU_1.info
/omd/sites/mysite/Timesyncd_Time.info

Next, you can either delete the .info files manually, or automatically, by replacing echo $i with rm $i in the provided oneliner. Like this:

Code Block
languagebash
themeRDark
OMD[mysite]:~$ for i in $(find ~/var/check_mk/rrd/myhost/CPU_Utilization_Packet_CPU_0.info

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 -name "*.info"); do test -e "${i%info}rrd" || rm "$i"; done


After you delete the affected files, you need to start the site

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and the

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required files will be recreated:

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languagebash
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OMD[mysite]:~$ omd start


Note

Checkmk does not delete any .rrd file. So it could be deleted by a custom cleaning job!

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