Wu's Blog

I got following error message when I try to run KVM Virtual Machine Manager: virt-manager on SSH. Gtk-WARNING **: cannot open display: There are several things need to be checked: Make sure " X11Forwarding " is set to " yes " in /etc/ssh/sshd_config on the machine you run  virt-manager . cat /etc/ssh/sshd_config | grep "^X11" If you are using Windows to connecting SSH. The X11 need to be forwarded to an "X Window server" on top of Windows. I use xming . If you connect SSH by Putty on Windows. Please configure X11 forwarding. Go to " Connection " -> " SSH " -> " X11 ". Check " Enable X11 forwarding ". Assign xming.exe path in " X authority file for local display ". If you are using  terminal on Mac OS. You need to install  Xquartz . It configures  terminal automatically. Now you are ready to use "virt -manager ".

When you load a PowerShell script you may see following error messages: Timed out waiting for the PowerShell extension to start If you see error logs, following appears: The language service could not be started One possible reason is your PowerShell executive policy is set to " AllSigned ". You can find the policy by run PowerShell command below. Get-ExecutionPolicy Run the following command in an elevated PowerShell window to change the policy. Set-ExecutionPolicy -ExecutionPolicy RemoteSigned  

You may see " The IP address to reach the server is not set " when clicking the KVM console in Cisco UCS Manager. The issue persists even Cisco UCS Manager has enough IP addresses for management. Re-acknowledge or reset CIMC cannot fix the problem. The fix procedure is go to " Equipment " -> Select the server -> " General " tab -> " Server Maintenance " -> " Decommission " the server. Wait for the decommission completed, then re-acknowledge the server. IP address will be assigned to the server after the acknowledge process is completed.

In recent LAB environment reviewing, I noticed my LAB ESXi hosts allow connections from all IP address for NTP services. This is not the best practices for the solid environment. I want to specify certain IP addresses are allowed in case of vulnerabilities in NTP services. There are a lot of blogs talking about how to enable/disable firewall ruleset but no one talks about how to do so. Following is what I figured out. Please let me know if you see anything I can improve. # Please connect to vCenter Server by Connect-ViServer before use this script. $vmhosts = Get-VMHost -Location esxiCluster foreach($vmhost in $vmhosts){ $esxcli=get-esxcli -vmhost $vmhost -V2 $ntpRuleSet = $esxcli.network.firewall.ruleset.set.CreateArgs() $ntpRuleSet.allowedall="false" $ntpRuleSet.rulesetid=" ntpClient " $esxcli.network.firewall.ruleset.set.Invoke($ntpRuleSet) $ntpAllowIP = $esxcli.network.firewall.ruleset.allowedip.add.CreateArgs() $ntpAllowIP.rulesetid=" ntpClient " $nt

If you are still using Windows 2008 for vCenter Server. You may see ESXi hosts lost connection back and forth on vCenter Server after recent Windows pathing. It's not something like a heartbeat lost for a few seconds. ESXi can takes minutes to back online. You can see similar logs in vpxd.log: 2018-08-03T09:24:23.337-04:00 error vpxd[20160] [Originator@6876 sub=HttpConnectionPool-000000] [ConnectComplete] Connect failed to <cs p:00000000200ed300, TCP:XXXXXXXXXXXXXXXX:443>; cnx: (null), error: class Vmacore::SystemException(Only one usage of each socket address (protocol/network address/port) is normally permitted) 2018-08-03T09:24:23.337-04:00 error vpxd[06332] [Originator@6876 sub=Vmomi opID=HB-host-28@307067-1d257f9c] [VpxdClientAdapter] Got vmacore exception: Only one usage of each socket address (protocol/network address/port) is normally permitted   2018-08-03T09:24:23.338-04:00 error vpxd[06332] [Originator@6876 sub=Vmomi opID=HB-host-28@307067-1d257f9c] [VpxdClientAdap