How to setup Cron jobs in ESXi host.

-

 Hi Everyone,

This post covers, how to run or schedule a Cron job in ESXi hosts. 

However, ESXi does not need to run a cron job, i never seen the cron job uses on ESXi platform as it is heavily use on Linux and Unix systems to automate the scripts.

But, few days back, i was getting struggled to one of my ESXi 6.5 host which is getting disconnected from vcenter in every 4-5 hours. It is also stopped to pinging as well. I have to restart the management agents to take back on the network via DCUI.

I tried to get the logs but didn't find the actual root cause of this issue. I didn't spend too much time to find the issue as well since it is a developement host running as a standalone.

I was thinking to rebuild it as well but several VMs running on this host and since it is development host, so we have a single logical volume which consists ESX footprint as well as VMs footprint.

So, i can't rebuild it anymore.

Now, I don't want to leave it as it is as well because the Development team was chasing me when VMs got unreachable so it will be a pain for me to do a restart of Management agent on the hosts daily basis.

I want a solution for this issue. So, i thought lets schedule a powershell script (As I am from Windows Background so powershell comes in mind first) to restart the management agent in every 2-3 hours and it can save my time to manually to do this.

But, later i thought to check shell script or anything which can be run locally from ESXi host. So, i found the cron job thing and i decide to schedule a cron job to restart the management agent on the host.

Let's do it now.

Login to ESXi via SSH or DCUI shell.

Run command 

# Cat /var/spool/cron/crontabs/root  >>>> this command will display you the all cron job list.

As you can see above, ESXi already uses some cron jobs to schedule several script for internal purpose.

Before changing the file, be sure to back it up just in case any issues.

Run below command to back the file.

#cp /var/spool/cron/crontabs/root /var/spool/cron/crontabs/root.old

Then, you can edit this file via below command.

#vi /var/spool/cron/crontabs/root

I have added the below parameter to restart the hostd and vpxa service in every 3 hours.

 

Our changes will not take effect until the crond services restart on the host.                                          

 Let's find out the crond service PID via below command.

 

Now, kill the crond PID via below command.

#kill 66612

Now, start the crond service and make sure PID number gets changed as well.

And, PID number gets change as well.

Hopefully, your command will execute as per the interval you set on the cron job.

Hope, this is informative, thanks. Cheers !!!

Comments

Post a Comment

Popular posts from this blog

How to migrate the N-VDS as the host switch to VDS 7.0 in NSX-T 3.x

-
Image
  Hello There, In this article, i am covering how to migrate the ESXi host switch from N-VDS to VDS 7.0 switch in NSX-T 3.2.x version. When using N-VDS as the host switch,  NSX-T  is represented as an opaque network in  vCenter Server . N-VDS owns one or more of the physical interfaces (pNICs) on the transport node, and port configuration is performed from  NSX-T Data Center . You can migrate your host switch to  vSphere  Distributed Switch (VDS) 7.0 for optimal pNIC usage and manage the networking for  NSX-T  hosts from  vCenter Server . When running  NSX-T  on a VDS switch, a segment is represented as an  NSX-T  Distributed Virtual Port Groups. Any changes to the segments on the  NSX-T  network are synchronized in  vCenter Server. We have an NSX-T environment running with NSX-T 3.2.2.1 version. this environment was designed and implemented with NSX-T 2.x version and that time we used the N-VDS as host switch configuration on the transport nodes bcuz VDS was not supported that time. 
Read more

vROPS appliances password remediation tasks failed from SDDC manager

-
Image
Issue details:-   Password remediation tasks on SDDC manager getting failed with below error. However, we are able to connect SSH with root password on the vROPS appliances, no issues with credentials. I checked Operations logs on SDDC manager and found below logs, indicating the SSH connectivity issues from SDDC to vROPS appliances. Tried to do SSH vROPS appliance from SDDC manager, getting below error... Seems some issue with ECDSA key.. Resolution:- SSH to vROPS appliance and retrieve the ECDSA ssh keys as below. Now, we have 2 options to update the correct SSH keys for vROPS appliance on SDDC manager known_Hosts files located at below location.   /root/.ssh/known_hosts   /etc/vmware/vcf/commonsvcs/known_hosts   /home/vcf/.ssh/known_hosts   /opt/vmware/vcf/commonsvcs/defaults/hosts/known_hosts First option is manually copy and paste the SSH key on all the known_hosts files and restart the SDDC manager services and then try to remediate the password again. it will be successful this
Read more

How to Import/Register a VM into vRA portal

-
Image
You can import an unmanaged virtual machine to a vRealize Automation environment. An unmanaged virtual machine exists in a vCenter but is not managed in a vRealize Automation environment and cannot be viewed in the vRA portal . Once you import an unmanaged virtual machine, the virtual machine is managed by using the vRealize Automation management interface. you can see the virtual machine on the Managed Machines tab or the Items tab. Please follow below steps to Import/Register VM into a vRA portal. Log in to vRealize Automation as a fabric administrator and as a business group manager. If you are importing virtual machines that use static IP addresses, prepare a properly configured address pool.  If you use bulk import to import a virtual machine with a static IP address that is allocated to another virtual machine, the import fails. Create a Blueprint and should not have even network attached as well. See below snapin. Create Network profile that shoul
Read more