Issues adding a single node cluster into management by VMM

image Recently we have seen an issue where a few customers have been experiencing errors and long delays in adding a single-node cluster (i.e. a 1 node cluster) under management in Virtual Machine Manager. The error that is displayed in the console is Warning (13926) that all of the nodes could not be contacted.

This issue stems from the fact that VMM has an overcommitted property for each cluster. By default, a single-node cluster will always be overcommitted since any failure in that single node will cause the entire cluster and its Virtual Machines to go down. Such a failure does not go well with the concept of high availability.

There really are two workarounds for this issue:

1. Set the node reserve failure to 0 in the cluster properties. Unfortunately this can only be modified once the cluster has been brought under management by VMM.

2. Add a second temporary node to the cluster simply for the purposes of adding it to VMM.  Then the second node can be removed.

Eventually the single node cluster will be added to the VMM console.  However, this process can take a very long time.  To expedite this process, it may be necessary to cycle the vmmservice. 

Hope this helps,

Mike Briggs | Senior Support Escalation Engineer