check_mk How to fix:Disk Mount Changes showing error

Sometimes few hosts in my check_mk build showing Disk Mount error.

For example:
“Mount options of / – – – – CRIT – mount options are
> > > acl,barrier=0,data=ordered,errors=remount-ro,noatime,rw,user_xattr,
> > > expected are barrier=0,data=ordered,errors=remount-ro,noatime,rw”

But there isn’t any changes recently.

I just su to my site and refresh the hosts manually:

Restart the check_mk, that will make the nonsense error goes away.

check_mk ALL Hoststate down, check_icmp: Failed to obtain ICMP socket: Operation not permitted

I upgrade my production check_mk site to the latest 1.2.8p14.

Suddenly all Hosts shows down.

Restart the site, everything back to normal.

This happens after I update check_mk to the latest stable Version: 1.2.8p14
Hope it helps.

check_mk outdate error message: Disk Mount Changes network interface speed wrong

A lot time I got these kind of wrong error message like:

Disk Mount changes but missing mount option.
Or Network interface 1 is 10GB but should be 1 GB.

Which is just the check_mk output outdate issue.

Here is what I do to refresh the $host in check_mk:

Sometimes I have to restart omd site, but it should be enough to give you back the correct output.

mongodb 3.2 logrotate

Installed latest mongodb 3.2 on Debian 8 Jessie.

It does not came with logrotate configure file.

Here is mine:

Add reopen in /etc/mongod.conf

Using -SIGUSR1 to rotate the log file:


check_mk agent start by systemd Debian Jessie

I use check_mk everywhere.

For the old school, on Debian system you need install xinetd to start it.
But since we have systemd in Debian 8 Jessie, it will be much cleaner to do systemd way.

Here is how I do it:

  1. Fist if you previous using xinetd, stop and remove it.
  2. And run autoremove to cleanup

  3. Then check your check_mk agent version:
  4. Next enable the check_mk in systemd autostart.
  5. Finally start the service.
  6. A special notice, because the systemd not allow the IP rules like xinetd does.
    You will have to update your firewall to restrict other accessing.

    Hope this helps, please let me know if you have any questions.

replace with sed in directory and sub directories

  1. # goto the folder
  2. # verify how many strings exist.
  3. # replace
  4. # double check the result.

How to put Cache into RamDisk

I recently upgrade memory on working PC.
Want put cache into Ramdisk and save some life of SSD.

The Ramdisk Application I am using is: SoftPerfect RAM Disk.

Here are my changes:

    1. Put Google Chrome Cache into RamDisk:

    1. Put Firefox Cache into RamDisk:

    1. Put VLC Media Player ART into RamDisk:

    1. Put Microsoft Edge Cache into RamDisk:

I accident delete the Edge profile folder.

Do not delete the top folder!

Recovery from PowerShell:

    1. Redirect the Temp folder even I change the Windows TEMP Path:

    1. Thumbcache folder can’t be redirect!

Keepalived not detect haproxy status on Debian Jessie

Keepalived not detect haproxy status on Debian Jessie

vi /etc/keepalived/keepalived.conf

The reason is keepall command does not installed!

Just install

Then everything works fine.

Increase SNMP ping Timeout Period for Check_MK

If you are monitoring external devices through SNMP like Netapp Storage, it may throw out alert when the Device is busy or the connect time out.

Put this in your file:

Let check_mk server check 1 more time before it send alert after the first one fail.
The wait time out increase to 30 seconds.
These lines apply changes on all of your SNMP machines having the tag snmp.

To force checm_mk client and ping run second checking if first one fail, add these into ~/etc/check_mk/

Then restart OMD/Check_MK to make it works.

How to clone a 2 TB Oracle Database VM at 3:00 AM

I have to clone a 2 TB Oracle Database VM at 3:00 AM.

Don’t want get up at 3:00 AM just for clone.

Create a Scheduled Task to Clone a Virtual Machine

This procedure creates a scheduled task to clone a virtual machine.

  1. Start the vSphere client, and log in to the vCenter Server system.
  2. From the Home page, click Scheduled Tasks.
  3. Select File > New > Scheduled Task, or click New. The Select a Task to Schedule dialog box appears.
  4. Select Clone a virtual machine from the drop-down menu, and click OK. The Clone Virtual Machine wizard appears.
  5. Select the virtual machine to clone and click Next.
  6. Follow the wizard through the same steps as those in the previous task in which you cloned a virtual machine.
  7. Enter a name and a task description in the text box.
  8. Select the frequency of the task.
  9. Select Now or Later. If later, enter the time and date when you want the virtual machine to be deployed, and click Next. To see the calendar, click Later, and click the drop-down arrow to select a date from the calendar. A red circle indicates today’s date, and a dark circle indicates the scheduled date.
  10. Review the information on the Ready to Complete New Virtual Machine page, and click Finish.

Optionally, you can select the check box to power on the new virtual machine after it is created.