Wu's Blog

My IT Adventure

  • 虚拟主机无法获得DHCP IP地址

    刚解决了一个问题，快速更新一下。当虚拟主机无法获得DHCP IP地址时，应该做的第一件事情是检查防火墙，无论是Windows防火墙或者物理防火墙。UDP端口67和68不能被阻挡掉。否则会出现虚拟主机只能获得169.x.x.x的IP地址，这个地址是不可用的，表示虚拟主机无法从DHCP服务器获得地址。

    这两个端口是DHCP客户端用来从DHCP服务器获取IP地址的。具体的技术细节可以参考RFC文档。

    DHCP uses UDP as its transport protocol. DHCP messages from a client

    to a server are sent to the ‘DHCP server’ port (67), and DHCP

    messages from a server to a client are sent to the ‘DHCP client’ port

    (68). A server with multiple network address (e.g., a multi-homed

    host) MAY use any of its network addresses in outgoing DHCP messages.

    我在排错过程中也用到了这篇文章。

  • 搜索虚拟主机时提示：Login To The Query Service Failed

    使用vSphere Client登录vCenter Server 6.0时可能会出现如下报错信息：

    Login to the query service failed.

    The server could not interpret the communication from the client. (The remote server returned an error: (500) Internal Server Error.)

    这是因为在登录vSphere Client时勾选了”Use Windows session credentials“。试试取消它。

    相关知识库链接：Searching the Inventory with the vSphere Client fails (2143566)

  • Login To The Query Service Failed When Search Virtual Machine

    You may see following problem if you login vCenter  Server 6.0 by vSphere Client:

    Login to the query service failed.

    The server could not interpret the communication from the client. (The remote server returned an error: (500) Internal Server Error.)

    That’s because “Use Windows session credentials” checkbox is selected. Deselect it and give it a try.

    Refer KB Searching the Inventory with the vSphere Client fails (2143566)

  • Virtual Machine Cannot Get DHCP IP Address

    Just a quick post. When virtual machine cannot get DHCP IP address the first thing you want to check is firewall. Whatever Windows firewall or physical firewall. You should make sure UDP port 67 and 68 are not blocked. Otherwise you  will see the virtual machine gets 169.x.x.x IP address only.

    The two  ports is required for DHCP client to query IP addresses. The methodology is introduced in RFC document.

    DHCP uses UDP as its transport protocol. DHCP messages from a client
    to a server are sent to the ‘DHCP server’ port (67), and DHCP
    messages from a server to a client are sent to the ‘DHCP client’ port
    (68). A server with multiple network address (e.g., a multi-homed
    host) MAY use any of its network addresses in outgoing DHCP messages.

    I also got some ideas in this post.

  • Adobe Flash Player Out of Date on vSphere Web Client

    You may see ‘Adobe Flash Player Out of Date’ on Chrome when you open vSphere Web Client. Click the text Chrome will update Flash Player automatically. But in some cases it doesn’t work due to maybe your Chrome is controlled by company policy or internet problem to Adobe.com. I found an article to show how to offline fix the issue. You can download Flash Player for Opera and Chromium-based browsers – PPAPI in official Adobe KB article.

    You may also want to check out my other articles about Flash issue on browsers.

    Flash menu appears when right click on vSphere Web Client in Chrome

    Cannot open vSphere Web Client on IE11 on Windows 8.1

  • Network Latency on Virtual Machine

    Slight network latency may cause application problem  on sensitive virtual machines. Even the network responding time is just 3 or 7 ms. There is a way to improve the  stability of responding latency – Enable RSS on NIC.

    Network traffic is handled by single CPU core when RSS is disabled. Enable it will distribute the workload to 4 cores by default. You can increase CPU for RSS by change registry.

    To summarize the solution. Go to Device Manager -> NIC properties -> Advance -> Find RSS option  and enable it. You will see 2 – 3 network drops when applying it.

    You can refer following articles for detail.

    Poor network performance or high network latency on Windows virtual machines

    Virtual Receive-side Scaling in Windows Server 2012 R2

    Regarding increase CPU for RSS. Read following article to learn how to modify it.

    Setting the Number of RSS Processors

  • vRealize Operation Manager Installation Pending on install.sh

    If your company implemented firewall and blocked public NTP server, you may see installation of vRealize Operation Manager pending on ./install.sh on console. That’s because the installer tries to negotiate with NTP server www.iana.org. The firewall blocked the traffic.

    VMware TAM Manager Shan told me  there are two options on firewall to block traffic: REJECT and DROP. REJECT means firewall responding to the request and let source device knows it’s rejected. DROP means firewall immediately ignores the request and no responding to source device. Looks like there is a bug in vROPs code that it hung if NTP request gets drop and no responding.

    The workaround is create a port group without physical uplinks and install vRealize Operation  Manager. Then move it to proper network after installation  is completed. You can configure correct IP addresses when import the OVF file so later on you just need simply move the network.

  • ESXi 6.0 and 6.5 hosts no responding issue!

    The smartd service  can leads to ESXi 6.0 or 6.5 hosts no responding due to out of memory. I see that issue on ESXi 6.0 U2 and U3 both. I would recommend stay on  ESXi 5.5 U3 at this moment.

    We do see the issue persist even after stop smartd service.

    Check out VMware official KB.

  • Windows 2016 is not available in OS option when create virtual machine

    Just noticed a gap here. If your  ESXi host is 5.5 Update 2 or earlier version, you are not able to choose ‘Windows Server 2016’ as operating system  when  you create virtual  machine. It’s addressed in  KB https://kb.vmware.com/kb/2132789.

  • Flash menu appears when right click on vSphere Web Client in Chrome

    There is a KB describes how to fix right click issue in IE on vSphere Web Client. But my problem was in Chrome. I searched a lot in internet but no lucky till today.

    The problem was flash menu appears when I right click anything in vSphere Web Client in Chrome. I have two computers that both has Chrome installed but one has issue, other one works fine. I compared version of Chrome, noticed working one was 55.x, problematic one was 49.x. The issue gone after upgraded to 57.x.

    After dig into that problem, looks like Google fixed the problem on version 54.0.2840 that there was a bug related to right click. Check out release notes here.

     

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