0035 Complex Hosts
In the virtualized hardware world there are three broad categories of host.
A BareMetalComputer describes a connected set of physical hardware. The open metadata types today do not attempt to model hardware in detail but this could be easily added if a contributor with the appropriate expertise was willing to work on it.
A VirtualMachine provides virtualized hardware through a hypervisor that allows a single physical bare metal computer to run multiple virtual machines.
A VirtualContainer provides the services of a virtualized operating system to the software processes running in it. When the server makes operating system requests, the VirtualContainer delegates the requests to the equivalent services of the actual host it is deployed on. DockerContainer provides a specific type of a popular container type called docker.
The hosts can actually be virtualized through many levels. The HostedHost relationship is used to represent the layers of virtualized hosts.
A HostCluster describes a collection of hosts that together are providing a service. Clusters are often used to provide horizontal scaling of services. The host cluster is linked to the hosts it is managing using the HostClusterMember. There are two specific types of host clusters defined:
HadoopCluster - describes a Hadoop cluster - that uses multiple bare metal computers/virtual machines to manage big data workloads.
KubernetesCluster - describes a Kubernetes cluster - that manages containerized applications across multiple bare metal computers/virtual machines.
In both Hadoop and Kubernetes the hosts that they manage are often referred to as “nodes”. The containerized applications managed by Kubernetes are represented as VirtualContainers.
Within the host cluster is typically a special host (node) that is controlling the execution of the other members. This host is modelled with a SoftwareServerPlatform that describes the cluster management platform, a SoftwareServer that groups the SoftwareServerCapabilities needed to manage the cluster. These software server capabilities are linked to the ITInfrastructure assets that are being managed by the cluster using the ServerAssetUse relationship.
0030 Hosts and Platforms describes how the software installed on a host is represented. 0037 Software Server Platform describes the software process that run on a host. 0045 Servers and Assets describes the relationships that manage assets such as ITInfrastructure.
- DeployedVirtualContainer - use HostedHost which is more general.
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