VMware chief executive Paul Maritz has labelled rival cloud platform OpenStack as "relatively immature", pointing towards the open source community's key partner Microsoft as a greater worry in the short-term.
Since forming in 2010, the open source OpenStack community has attracted backers from significant user organisations including NASA, as well as vendors Microsoft, Citrix, Dell and cloud provider Rackspace.
It also gained support in March last year for VMware's vSphere virtualisation platform through development work from rival Citrix.
Maritz told analysts late last week that the company expected increased competition from rival vendors in the cloud and particularly virtualisation markets, and that it was "highly unlikely that we would be left alone to have that opportunity all to ourselves".
"That being said, OpenStack at this point compared to the vSphere environment is still relatively immature," he said.
"We continue to believe that our greater near-term challenge would probably come from Microsoft."
VMware last year established a similar platform in opposition, Cloud Foundry, and recently announced plans from eBay subsidiary X.commerce to use the service.
Maritz indicated that OpenStack could grow to become a formidable competitor in the future and that the company would "certainly take all of the competing cloud technologies very seriously".
He did not elaborate on what specific elements of Microsoft's cloud or virtualisation strategies come as a threat to VMware's own.
VMware notched up US$1 billion in sales for the first quarter of this year, a 25 percent increase on the period and a 52 percent increase in net income. The company did not provide separate sales or licensing figures for its vSphere platform, which rivals the community-based OpenStack.