# Docker

So far this document has covered how to add the VMware cloud integration and has enabled users the ability to provision virtual machine based instances via the Add Instance catalog in Provisioning. Another great feature provided by VM Essentials out of the box is the ability to use Docker containers and even support multiple containers per Docker host. To do this a Docker Host must first be provisioned into VMware (multiple are needed when dealing with horizontal scaling scenarios).

To provision a Docker Host simply navigate to the Clusters tab of the Cloud detail page or Infrastructure > Clusters section. From there, click + ADD CLUSTER to add a VMware Docker Host. This host will show up in the Hosts tab next to other ESXi servers that were inventoried by the VMware cloud integration. VM Essentials views a Docker host just like any other Hypervisor with the caveat being that it is used for running containerized images instead of virtualized ones. Once a Docker Host is successfully provisioned a green checkmark will appear to the right of the host marking it as available for use. In the event of a failure click into the relevant host that failed and an error explaining the failure will be displayed in red at the top.

Some common error scenarios include network connectivity. For a Docker Host to function properly, it must be able to resolve the VM Essentials appliance url which can be configured in Administration > Settings. If it is unable to resolve and negotiate with the appliance than the agent installation will fail and provisioning instructions will not be able to be issued to the host.
