Wednesday 28 September 2011

Ghost VMkernel Adapter

I came across a strange issue recently when configuring a new vDS in vSphere 5.  I had already configured two VMkernel adapters but for some reason one of them half created.  Only one was visible when viewing the vDS settings on the host:


When attempting to create a new one I’d receive a message stating that one already existed (apologies I don’t have the screen shot as I fixed it before creating this post).  I was unable to locate this within vCenter or even when connecting directly to the host.  Only way I could resolve it was to enable and connect to the host via SSH and list all VMkernel adapters with the following command:

esxcli network ip interface list


Now I could see the offending adapter.  Next option was to remove it:

esxcli network ip interface remove –i <Adapter name>


Now when listing the adapters again it was successfully remove and could be re-added again within vCenter.

Wednesday 10 August 2011

Book Review - vSphere Clustering - Technical Deepdive

Duncan Epping and Frank Denneman have done it again.  Following the success of HA and DRS - Technical Deepdive for vSphere 4.1 they have released vSphere Clustering - Technical Deepdive for vSphere 5

The book is available in Black and White, Colour and also for the Kindle.  I opted for the full fat colour version which I ordered from the USA as it wasn't available in the UK.  The full colour version doesn't disappoint due to the sheer amount of diagrams used to explain some of the concepts.

Chapters 1 through 9 go through vSphere High Availability (HA) and also go in depth over the changes in HA with vSphere 5.  No longer do we have the concept of primary and secondary nodes and the issues that can arise in the event of losing all primary nodes. vSphere 5 HA was completely re-written and uses FDM (Fault Domain Manager) which has the concept of master and slave nodes within a cluster.  The book also goes in depth about the new HA datastore heartbeat which can be used in the event of loss of the management network.  HA is one of those features that people take for granted since it can pretty much be configured with a few clicks and "just works".  These chapters go into the inner workings of HA and are a must for anyone designing vSphere environments.

Chapters 10 through 19 go in depth, and I mean really in depth, in the changes to Distributed Resource Scheduler DRS within vSphere 5.  Once again, DRS is one of those technologies than can be enabled with a few clicks and pretty much forgotten about.  These chapters explain every inch of DRS and how it goes about making the decisions that ultimately affect where a VM is migrated or a host is powered down to save power consumption.  Some of the concepts can be quite difficult to follow but nearly all discussions are followed up with flow diagrams that further explain the theory.  I found myself having a read some sections a couple of times to let the information sink in and then the flow diagrams reinforced it.

Chapters 20 through to 26 explain about the new vSphere Storage DRS (SDRS).  This is a new feature in vSphere 5 that allows monitoring of datastores for disk space and disk latency and either make recommendations or, in automatic mode, perform the actual recommendation.  SDRS will ensure all datastores are load balanced for disk IO and space as best it can whilst also taking into consideration any affinity or anti affinity rules you have.  The chapters explain all setting (including advanced) that you have at your disposal and how certain decisions can affect others.

Once again, the guys have produced an excellent technical resource that just shows that HA, DRS and SDRS are extremely useful and advanced features of vSphere that all production environments should utilize.

Tuesday 5 July 2011

UK North East vBeers

Interested in VMware?
Live in/or near the North East of England?
Like beer?

Then why not join the UK North East vBeers first meeting:

Time to start blogging again...

I've been pretty slack recently in blogging and I'm going to try and change going forward.  Work's been pretty hectic over the last few months with an Exchange 2003 to Exchange 2010 migrations (Which is nearly finished) and various other projects.  I now have a bit of time free to concentrate on rebuilding my home vSphere lab.  I'm planning on rebuilding the entire environment including all VM's due to the various changes that have been made to the over the years.  I'll hopefully keep you updated.