After updating/restarting the manager to v14.2.5 we are no longer able to send data to our zabbix servers. Ceph reports a non-zero exit status from zabbix_sender.

Info:

ceph mon versions
{
    "ceph version 14.2.6 (ba51347bdbe28c7c0e2e9172fa2983111137bb60) nautilus (stable)": 3
# cat /etc/debian_version
10.2
root@px1 /etc/network # cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 10 (buster)"
NAME="Debian GNU/Linux"
VERSION_ID="10"
VERSION="10 (buster)"
VERSION_CODENAME=buster
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"
# ceph -s
  cluster:
    id:     20a806df-b3f4-4032-ab8e-ae15aef1e836
    health: HEALTH_WARN
            Failed to send data to Zabbix
            mon px1 is low on available space

  services:
    mon: 3 daemons, quorum px1,px2,px3 (age 8d)
    mgr: px1(active, since 8d), standbys: px2, px3
    osd: 32 osds: 32 up (since 8d), 32 in (since 11d)

  data:
    pools:   7 pools, 640 pgs
    objects: 3.52M objects, 13 TiB
    usage:   53 TiB used, 124 TiB / 176 TiB avail
    pgs:     639 active+clean
             1   active+clean+scrubbing+deep

  io:
    client:   0 B/s rd, 23 MiB/s wr, 0 op/s rd, 34 op/s wr

# ceph health detail
HEALTH_WARN Failed to send data to Zabbix; mon px1 is low on available space
MGR_ZABBIX_SEND_FAILED Failed to send data to Zabbix
    /usr/bin/zabbix_sender exited non-zero: zabbix_sender [4088351]: DEBUG: answer []
zabbix_sender [4088351]: Warning: incorrect answer from server []

Setting “debug mgr = 20” yields no additional information. Zabbix configuration in ceph has not changed since the v14.2.5 update, and was working under v14.2.4:

# ceph zabbix config-show
{"zabbix_port": 10050, "zabbix_host": "stats.myzabbix.host", "identifier": "px1.cephserver.host", "zabbix_sender": "/usr/bin/zabbix_sender", "interval": 60}

So, how to reconfigure it.
SOME DETAILS:

Zabbix plugin

The Zabbix plugin actively sends information to a Zabbix server like:

Ceph status

I/O operations

I/O bandwidth

OSD status

Storage utilization

Requirements

The plugin requires that the zabbix_sender executable is present on all machines running ceph-mgr. It can be installed on most distributions using the package manager.
Dependencies

Installing zabbix_sender can be done under Ubuntu or CentOS using either apt or dnf.

On Ubuntu Xenial:

# apt install zabbix-agent

On Fedora:

# dnf install zabbix-sender

Enabling

You can enable the zabbix module with:

# ceph mgr module enable zabbix

Configuration

Two configuration keys are vital for the module to work:

zabbix_host

identifier (optional)

The parameter zabbix_host controls the hostname of the Zabbix server to which zabbix_sender will send the items. This can be a IP-Address if required by your installation.

The identifier parameter controls the identifier/hostname to use as source when sending items to Zabbix. This should match the name of the Host in your Zabbix server.

When the identifier parameter is not configured the ceph- of the cluster will be used when sending data to Zabbix.

This would for example be ceph-c4d32a99-9e80-490f-bd3a-1d22d8a7d354

Additional configuration keys which can be configured and their default values:

zabbix_port: 10051

zabbix_sender: /usr/bin/zabbix_sender

interval: 60

Configuration keys

Configuration keys can be set on any machine with the proper cephx credentials, these are usually Monitors where the client.admin key is present.

ceph zabbix config-set

For example:

# ceph zabbix config-set zabbix_host zabbix.localdomain
# ceph zabbix config-set identifier ceph.eu-ams02.local

The current configuration of the module can also be shown:

# ceph zabbix config-show

Manually sending data

If needed the module can be asked to send data immediately instead of waiting for the interval.

This can be done with this command:

# ceph zabbix send

The module will now send its latest data to the Zabbix server.
Debugging

Should you want to debug the Zabbix module increase the logging level for ceph-mgr and check the logs.

[mgr]
    debug mgr = 20

With logging set to debug for the manager the plugin will print various logging lines prefixed with mgr[zabbix] for easy filtering.

When trying to Enabling Physical GPUs in Hyper-V, the option is not there in the GUI. In Windows 2016 there is an option as in the below screenshot:

 

In Windows Server 2019, here is the screenshot and there is no option to enable it:

 

So, Here is how to enable it in Windows server 2019. You can also use RemoteFX vGPU feature on Windows Server 2019. Although the config UI of RemoteFX vGPU has been removed from Hyper-V Manager of Windows Server 2019, you can configure RemoteFX vGPU by using Powershell on Windows Server 2019.

Check your Host GPU – You need RemoteFX Compatible GPU Card and you need to install the Remote Desktop Virtualization Host role in Windows Server Manager.

To install the Remote Desktop Virtualization Host role, open Server Manager, and select the Add Roles and Features option from the Manage menu. This will cause Windows to launch the Add Roles and Features Wizard. Click Next to skip the wizard’s Before You Begin screen. You will now be taken to the Installation Type screen. Select the Role-Based or Feature-Based Installation option and click Next. You will now be prompted to choose the server on which you wish to install the role. Choose the Select a Server from the Server Pool option. Make sure that the correct server is selected, and click Next. You should now see the Select Server Roles screen. Select the Remote Desktop Services role, and click Next. Click Next again to bypass the Features screen, and once again to bypass the Remote Desktop Services introduction.

The next screen that you will see asks you to select the role services that you wish to install. Select the Remote Desktop Virtualization Host checkbox, as shown below. If prompted to install the Media Foundation and the Remote Server Administration Tools, be sure to click the Add Features button.

Click Next, followed by Install, and the required role services will be installed onto the server. When the process completes, click Close. You will need to reboot the server in order to finish the installation.

Now open powershell as Administrator.

Run the following commands:

Get-VMRemoteFXPhysicalVideoAdapter

Look for the following:

CompatibleForVirtualization: True
Enabled: True

Here is the screenshot for the Nvidia card I have. Make a note of the name of the card as well.

You can also use the name of the card directly or with a wildcard as below:

Next, Enable/Disable Host GPU for RemoteFX vGPU. To Enable, run this:

PS C:\> Get-VMRemoteFXPhysicalVideoAdapter -Name *Nvidia* | Enable-VMRemoteFXPhysicalVideoAdapter

Next, stop the VM on hyper V. Then, Add RemoteFX vGPU to your VM:

Example: Add-VMRemoteFx3dVideoAdapter -VMName [vm_name]

Add-VMRemoteFx3dVideoAdapter -VMName [Windows10]

Now, open the VM Settings in Hyper V so you can configure RemoteFX vGPU. You should see this:

5) Start VM.

 

Other Resources:

1. https://techcommunity.microsoft.com/t5/windows-server-for-it-pro/server-2019-hyper-v-vm-using-gpu/m-p/303761
2. https://social.technet.microsoft.com/Forums/forefront/en-US/738f05a3-a8d2-49ca-a82a-d356b83e1cd4/hyperv-quotremotefx-3d-video-adapterquot-gone-in-windows-10-1809
3. http://techgenix.com/enabling-physical-gpus-hyper/
4. https://docs.microsoft.com/en-us/powershell/module/hyper-v/enable-vmremotefxphysicalvideoadapter?view=win10-ps
5. https://social.technet.microsoft.com/wiki/contents/articles/16652.remotefx-vgpu-setup-and-configuration-guide-for-windows-server-2012.aspx?wa=wsignin1.0&CommentPosted=true

If you get the following error message the first time that you access Windows after installation,

then your client has been negotiating with the server for network level authentication.

However, network level authentication is executed before a remote desktop session has even been created.

That means that you cannot perform the forced password change during the first login.
Temporarily disabling network level authentication

To make the password change take place despite this, you must first temporarily disable network level authentication.

To do this, first, create a RDP file:

The save the file as Newconnection.rdp

Now, open the file with notepad and add the following line at the bottom:

Save it. Now click on it to open and login.

Connect to a Plesk server via SSH.

Create a copy “postfix” configuration file:

# cp -a /etc/postfix/main.cf /root/backup_main.cf

Open “postfix” configuration file in a text editor, for example, “vi” editor:

# vi /etc/postfix/main.cf

Add the lines specified below to the configuration file main.cf and make sure that these lines are present only once in the file:

Note: replace example.com with required mail server name.

myhostname = example.com
smtpd_banner = $myhostname ESMTP $mail_name

Using command line tool. check “postfix” configuration syntax and restart postfix:

postfix check
(empty output - means syntax is OK)
# service postfix restart

To find out where disk space is being used:

Get to the root of your machine by running

# cd /

Run

# sudo du -h --max-depth=1

Note which directories are using a lot of disk space.
cd into one of the big directories.
Run

# ls -l

to see which files are using a lot of space. Delete any you don’t need.
Repeat steps to run once you cd into the directory with the largest size

sudo du -h --max-depth=1

FTP is not working and has the following error:
421 Service not available, remote server has closed connection

Also, in the message logs:
Plesk Unable to FTP – missing scoreboard file (Linux)

On CentOS 6 and 7 if you experience issues logging on to FTP server please check the logs for the following:

# tail -f /var/log/messages

Look for this error:

proftpd[11951]: fatal: ScoreboardFile: : unable to use '/var/run/proftpd/scoreboard': No such file or directory on line 74 of '/etc/proftpd.conf'

Check in /var/run for a proftpd folder, if it’s missing you have a bug in your ProFTPd version usually caused by using the Atomic repo to update ProFTPd.

Check for atomic:


# ls -la /etc/yum.repos.d/ | grep atomic
-rw-r--r--.   1 root root   827 May 18  2016 atomic.repo

The solution is to remove the package and reinstall from Plesk repo:


rpm -e --nodeps psa-proftpd
plesk installer --select-release-current --install-component=proftpd
service xinetd restart

Then you should be able to connect again. Please note that any changes to proftpd.conf such as enabling custom PassivePorts will be lost and need to be recreated.

Source: https://community.webcore.cloud/tutorials/plesk_articles/plesk_unable_to_ftp_missing_scoreboard_file_linux/