Web Solutions and Technical Support Resources





Boot a guest using PXE - Do it now

This article covers how to boot a guest using PXE. PXE booting is supported for Guest Operating Systems that are listed in the VMware Guest Operating System Compatibility list and whose operating system vendor supports PXE booting of the operating system.

The virtual machine must meet the following requirements:

1. Have a virtual disk without operating system software and with enough free disk space to store the intended system software.

2. Have a network adapter connected to the network where the PXE server resides.


A virtual machine is not complete until you install the guest operating system and VMware Tools. Installing a guest operating system in your virtual machine is essentially the same as installing it in a physical computer.


To use PXE with Virtual Machines:

You can start a virtual machine from a network device and remotely install a guest operating system using a Preboot Execution Environment (PXE). 

You do not need the operating system installation media. When you turn on the virtual machine, the virtual machine detects the PXE server.


To Install a Guest Operating System from Media:

You can install a guest operating system from a CD-ROM or from an ISO image. Installing from an ISO image is typically faster and more convenient than a CD-ROM installation. 


To Upload ISO Image Installation Media for a Guest Operating System:

You can upload an ISO image file to a datastore from your local computer. You can do this when a virtual machine, host, or cluster does not have access to a datastore or to a shared datastore that has the guest operating system installation media that you require.


How to Use a private libvirt network ?

1. Boot a guest virtual machine using libvirt with PXE booting enabled. You can use the virt-install command to create/install a new virtual machine using PXE:

virt-install --pxe --network network=default --prompt

2. Alternatively, ensure that the guest network is configured to use your private libvirt network, and that the XML guest configuration file has a <boot dev='network'/> element inside the <os> element, as shown in the following example:

<os>

   <type arch='x86_64' machine='pc-i440fx-rhel7.0.0'>hvm</type>

   <boot dev='network'/>

   <boot dev='hd'/>

</os>

3. Also ensure that the guest virtual machine is connected to the private network:

<interface type='network'>

   <mac address='52:54:00:66:79:14'/>

   <source network='default'/>

   <target dev='vnet0'/>

   <alias name='net0'/>

   <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>

</interface>

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Internal error Account getPassword cannot decrypt password to be plain - Fix this Plesk error Now

This article covers how to resolve Plesk error, 'Internal error: [Account :: getPassword] cannot decrypt password to be plain'. It happens when A database user whose password is encrypted can now import and export the domain database after providing the database password.

However this issue is resolved in Plesk Obsidian.


To fix this Plesk error:

1. Updating Plesk via the Plesk interface

Make sure that port 8447 is opened in a firewall. If it is closed and cannot be opened for some reason, use the command-line instructions.

i. In Plesk, go to Tools & Settings and click Updates and Upgrades.

ii. On the Updates and Upgrades page, click Update Components.

iii. Click Continue to begin the update procedure.

2. Updating Plesk via a command-line interface

i. Connect to a Plesk server via SSH (Linux) / RDP (Windows Server).

ii. Run Plesk Installer Update (on Windows Server, start a command prompt as an Administrator):

plesk installer update


By default, Plesk installs updates automatically by means of the Plesk daily task (executed every night), if the option Automatically install Plesk updates is enabled at Tools & Settings > Update Settings.

During the update process:

1. Plesk may go offline for several minutes, if updates require a Plesk restart

2. Websites will stay online

Note: If a service component is going to be updated, its service will be restarted.


To find out what Plesk update is currently installed on the system, go to the Home page > System Overview.

Alternatively, execute the following command in a command-line interface:

plesk version

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Unlock a file locked by any process or system - Do it now

This article covers how to unlock a file locked by any process or system. 

If everything goes correctly, you will fix this Windows problem without killing the process and – more importantly – without having to reboot the system.


To unlock a locked file in Windows 10?

1. Type the name of the locked file in the field, and click the Search button. 

2. Select the file from the search result. 

3. Behind the search window, in "Process Explorer," right-click the locked file, and select Close Handle to unlock it.


To Open a Locked File When Another Program Is Using It:

1. Close The Program That Is Using The Locked File.

2. Kill The Program Process Using Task Manager.

3. Turn Off The Preview Pane In File Explorer.

4. Toggle The Folder Process In File Explorer.

5. Launch & Close The Locked File.

6. Restart Your Windows Computer.

7. Use Command Prompt To Delete The File.

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Apply Configuration Fails in Nagios Server - Resolve this issue now

This article covers solutions to when Apply Configuration Fails in Nagios Server. This issue happens when the Nagios XI server is unable to resolve the "localhost".

The error message will look like this:

Apply Configuration fails with the following error:

Backend login to the Core Config Manager failed.
An error occurred while attempting to apply your configuration to Nagios Core.
Monitoring engine configuration files have been rolled back to their last known good checkpoint.


To resolve this Nagios Problem:

1. Edit your /etc/hosts file and make sure there are localhost entries. For example:

127.0.0.1    localhost.localdomain    localhost.localdomain    localhost4    localhost4.localdomain4    localhost    xi-c6x-x64

::1    localhost.localdomain    localhost.localdomain    localhost6    localhost6.localdomain6    localhost    xi-c6x-x64

2. After making these changes try and "Apply Configuration" from Core Configuration Manager and your problem should be resolved.

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Apply Configuration never completes in Nagios - Fix this issue now

This article covers methods to resolve the issue, Apply Configuration never completes in Nagios. The backend components in Nagios XI require high level privileges, these are accommodated for in sudoers entries.

This allows for high level commands to be executed by scripts without requiring user input. If these entries are missing then they can cause unexpected results.


Sometimes when creating a large amount of objects the apply configuration process is taking longer than expected and PHP may time out or exceed limits.

These are defined in the php.ini file, The location of the php.inifile differs depending on your operating system / version. The following command will determine the location:

find /etc -name php.ini

If there are multiple results then the one in the apache directory is the one that needs changing.

Edit /etc/php.ini and increase these values:

max_execution_time = 60

max_input_time = 60

memory_limit = 256M

 

After making these changes you'll need to restart the Apache service using one of the commands below:

RHEL 7 | CentOS 7 | Oracle Linux 7

$ systemctl restart httpd.service

Debian | Ubuntu 16/18

$ systemctl restart apache2.service

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Port 113 IDENT Requests - How to Disable it on Nagios

This article covers how to disable Port 113 IDENT Requests on Nagios. 

You are seeing port 113 return requests either from your Nagios XI server (when submitting NSCA passive results) to the originating host OR you are seeing port 113 return requests when checking NRPE services).

You will see this behavior on your firewall logs as you will most likely not have a firewall rule for port 113.

This is usually because you are running an NRPE check through XINETD with USERID included on the log_on_success or log_on_failure options in your remote hosts /etc/xinetd.d/nrpe file.

OR this could be because you are submitting passive results to the XI server through NSCA (which is running under XINETD) /etc/xinetd.d/nsca with the same options as above.


To disable Port 113 IDENT Requests:

1. Then remove the USERID option from the log_on_failure AND log_on_success to stop the IDENT from occurring. The file you need to change depends on:

i. NRPE on remote host

/etc/xinetd.d/nrpe

ii. NSCA on Nagios XI server

/etc/xinetd.d/nsca

2. After making the changes you need to restart the xinetd service using one of the commands below:

RHEL 7+ | CentOS 7+ | Oracle Linux 7+ | Debian | Ubuntu 16/18/20

$ systemctl restart xinetd.service


What is filter ident port 113?

Filter IDENT(port 113) (Enabled) IDENT allows hosts to query the device, and thus discover information about the host.

On the VPN Passthrough screen, you can configure the router to transparently pass IPSec, PPPoE, and PPTP traffic from internal hosts to external resources.

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