vCloud Director, RHEL 6.3, and Windows Server 2012 NFS

July 16th, 2013 by jason Leave a reply »

One of the new features introduced in vCloud Director 5.1.2 is cell server support on the RHEL 6 Update 3 platform (you should also know that cell server support on RHEL 5 Update 7 was silently removed in the recent past – verify the version of RHEL in your environment using cat /etc/issue).  When migrating your cell server(s) to RHEL 6.3, particularly from 5.x, you may run into a few issues.

First is the lack of the libXdmcp package (required for vCD installation) which was once included by default in RHEL 5 versions.  You can verify this at the RHEL 6 CLI with the following command line:

yum search libXdmcp

or

yum list |grep libXdmcp

Not to worry, the package is easily installable by inserting/mounting the RHEL 6 DVD or .iso, copying the appropriate libXdmcp file to /tmp/ and running either of the following commands:

yum install /tmp/libXdmcp-1.0.3-1.el6.x86_64.rpm

or

rpm -i /tmp/libXdmcp-1.0.3-1.el6.x86_64.rpm

Update 6/22/18: It is really not necessary to point to a package file location or a specific version (this overly complicates the task) when a YUM repository is created. Also… RHEL7 Infrastructure Server base environment excludes the following packages required by vCloud Director 9.1 for Service Providers:

  • libICE
  • libSM
  • libXdmcp
  • libXext
  • libXi
  • libXt
  • libXtst
  • redhat-lsb

If the YUM DVD repository has been created and the RHEL DVD is mounted, install the required packages with the following one liner:

yum install -y libICE libSM libXdmcp libXext libXi libXt libXtst redhat-lsb

Next up is the use of Windows Server 2012 (or Windows 8) as NFS for vCloud Transfer Server Storage in conjunction with the newly supported RHEL 6.3.  Creating the path and directory for the Transfer Server Storage is performed during the initial deployment of vCloud Director using the command mkdir -p /opt/vmware/vcloud-director/data/transfer. When mounting the NFS export for Transfer Server Storage (either manually or via /etc/fstab f.q.d.n:/vcdtransfer/opt/vmware/vcloud-director/data/transfer nfs rw 0 0 ), the mount command fails with error message mount.nfs: mount system call failed. I ran across this in one particular environment and my search turned up Red Hat Bugzilla – Bug 796352.  In the bug documentation, the problem is identified as follows:

On Red Hat Enterprise Linux 6, mounting an NFS export from a Windows 2012 server failed due to the fact that the Windows server contains support for the minor version 1 (v4.1) of the NFS version 4 protocol only, along with support for versions 2 and 3. The lack of the minor version 0 (v4.0) support caused Red Hat Enterprise Linux 6 clients to fail instead of rolling back to version 3 as expected. This update fixes this bug and mounting an NFS export works as expected.

Further down in the article, Steve Dickson outlines the workarounds:

mount -o v3 # to use v3

or

Set the ‘Nfsvers=3’ variable in the “[ Server “Server_Name” ]”
section of the /etc/nfsmount.conf file
An Example will be:
[ Server “nfsserver.lab.local” ]
Nfsvers=3

The first option works well at the command line but doesn’t lend itself to /etc/fstab syntax so I opted for the second option which is to establish a host name and NFS version in the /etc/nfsmount.conf file.  With this method, the mount is attempted as called for in /etc/fstab and by reading /etc/nfsmount.conf, the mount operation succeeds as desired instead of failing at negotiation.

There is a third option which would be to avoid the use of /etc/fstab and /etc/nfsmount altogether and instead establish a mount -o v3 command in /etc/rc.local which is executed at the end of each RHEL boot process.  Although this may work, it feels a little sloppy in my opinion.

Lastly, one could install the kernel update (Red Hat reports as being fixed in kernel-2.6.32-280.el6). The kernel package update is located here.

Update 5/27/18: See also http://www.boche.net/blog/2012/07/03/creating-vcloud-director-transfer-server-storage-on-nfs/ for other new requirements when trying to mount NFS exports with RHEL 7.5.

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