Fix Ubuntu Server bash for internet accessing (DNS querying)

Posted on by Allen

I have multiple devices installed with Ubuntu Server. Some of them have a strange problem:
They can access internet using some applications, such as squid, without any problem.
They can ping to internet IP address.
They can use host / dig to query IP by domain name.
They cannot ping to internet by using domain name directly.
They cannot download file through wget / curl using domain name, but can do with IP.
They cannot use apt, stuck at connecting.
All they use a local dnsmasq as their dns.

After a long time dig, I found the problem and here is the fix.
open the file /etc/nsswitch.conf, search the line with “hosts:” and change the setting to “files dns” (without quotes).

Web Deploy for Visual Studio

Posted on by Allen

While I’m trying to deploy my site from Visual Studio to a Windows Server 2012 R2 instance, I have to dig a lot for troubleshooting about Web Deploy related problems.

 

Here are some not listed in Microsoft documents:

  • Visual Studio need both Web Deploy (Web Deployment Agent Service, MsDepSvc) and Web Management Service (WMSVC).
  • You cannot install Web Management Service separately.
  • The easy way to install the both is choose “Web Deploy 3.6 for Hosting Servers” Web Platform Installer.
  • If you selected “Web Deploy 3.6” in another release, without “for Hosting Servers”, Web Management Service will not be installed.
  • If you leave Web Deploy installed without Web Management Service, you could add it by install “Web Deploy 3.6 for Hosting Servers” but IT WILL NEVER WORK! You have to UNINSTALL existed Web Deploy first and then reinstall the “Web Deploy 3.6 for Hosting Servers”.

Install ubuntu server into Soekris net6501 by using USB boot

Posted on by Allen

This will guide you to prepare a installation media from Windows and install ubuntu into Soekris net6501.

Stuffs you need:

  • a USB stick that CAN BE RECOGNIZED by net6501 device.
    Not sure? Attach it to net6501 and reboot. If you can read the SIZE of this stick while booting, it is.
  • an ISO file for ubuntu server 32-bit. Version 16.10 is tested.
  • rufus. Guide and download point at https://www.ubuntu.com/download/desktop/create-a-usb-stick-on-windows.
  • a working serial connection from your workstation to your net6501, software included.

Prepare installation media:

  • Use rufus to build the USB stick. Check the guide above.

Install:

  1. Link net6501 to your computer using serial connection and start the link. In this case, I’m using the default setting (Speed=19200, Data bits=8, Stop bits=1, Parity=None, Flow control=XON/XOFF).
  2. Boot your net6501 with USB stick attached.
  3. Hit ctrl-p to go into bios.
  4. Type “boot 81” (without quotes) and press enter to boot from USB.
  5. You will see that something wrong with gfxboot.
  6. Type this text below SLOWLY and press enter. DO NOT COPY AND PASTE:
    install console=ttyS0,19200
  7. Do not press any key related to screen mode selection. It will be passed.
  8. Choose a language and continue installation steps as normal.

Finalize:

Grub configuration need to be adjusted for using serial as console.

Edit /etc/default/grub and change to these lines below:
GRUB_CMDLINE_LINUX_DEFAULT="quiet"
GRUB_CMDLINE_LINUX="console=ttyS0,19200 noplymouth"

Then run update-grub.

 

Hope this help you.

2017年春

Posted on by Allen

还记得年少时的梦吗。

 

怎样的一天才是有意义的，怎样的人生才能无愧于自己。是否世间只有唯一的标准，是否只能追逐尘世的喧嚣。
每个人有属于自己的一生，它的价值由自己把握，它的意义由自己诠释。虽然人生只有一次，但一次也已足够。虽然时间无法回头，但流逝才让生命存在价值。
每天最大的幸福，也许就是在睡前可以确信，自己没有虚度一天，准备好在下一个清晨，迎接新的一天的试炼。

祝大家在新的一年中的每一天，都能一点点的实现自己的理想，与自己年少时的梦近一点，再近一点。

Caution: SqlServer Cluster Update patch from WSUS

Posted on by Allen

Microsoft launched KB3194721 (for SqlServer 2012) and KB3194718 (for SqlServer 2014) this month though WSUS channel. If you choose to deploy them though WSUS, just as I did, you may face a bug on a cluster based SqlServer.

 

On the server with SqlServer installed as cluster, these patches just act as cancelled or failed. For digging the problem, I download the package from Microsoft Download Site and try to install them manually. The first step is decompressing. Files are placed on the largest drive (I dunno it based on the total or free space). In my case, one disk drive for a database role is chosen. Then the upgrading procedure starts, with a bug that is:

If the owner of this instance role of cluster is the same computer, the role will be automatically stopped during update process, and will be started later. But while the role is set to stop, the disk drive is offline with it. So, if that drive is the largest, sadly, the update procedure fails — source files of update package are missing.

 

Even you run these packages manually, not from WSUS, it’s still not possible to choose the folder to decompress. If some drive of database role of cluster is larger than all server self-owned disks, you may want to STOP THE NODE in cluster as a workaround.

Now Windows 10.0.14393 works well with WSUS

Posted on by Allen

Microsoft fixed the problem about Windows Update working with WSUS, finally after nearly 2 months.

When you fall in love with Spanned Volumes

Posted on by Allen

In our company, our major productive servers are hosted in vSphere as Windows-based virtual machines. Some of them need very big disks. Through the largest disk space supported in vSphere is 16TB (or maybe more, i dunno), I’m not interested to create such a big file in VMFS. It will be really a pain your *** when you have to move such a big file among datastores, even among data facilities by using portable hard drives.

Creating smaller disks instead of a big one for every Windows-based VM, IMHO.

Fortunately, Windows support to merge small disks as a big one, using dynamic disk function. There are 4 kinds of volume can be supported in such a condition: Spanned, Striped, Mirrored and RAID-5. You can consider them like JBOD, RAID-0, RAID-1 and RAID-5 functions in a simple legacy storage device.

Because data protection is existed in the SAN, Mirrored and RAID-5 volumes are not considered at all. Striped will make it a little faster when lots of virtual disks fight for limited IOPS resources within one datastore. But there is no way to extend any stripped volume (https://technet.microsoft.com/en-us/library/cc770938.aspx).

So, the useless volume format in a traditional world, spanned volume, is the best solution, maybe the only one. Next time when you need to create big virtual disks for Windows in any virtualization environment, don’t forget to consider using Spanned Volumes.