At the heart of ESX sits this kernel. Network access for host services (iSCSI, NFS, vSAN, vMotion, management and so on) goes through VMkernel adapters, also called vmknics.
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Terms in this definition
- ESX
VMware's bare-metal hypervisor, installed on each host in a VCF fleet. Up to version 9.0 it was known as ESXi.
- iSCSI
Protocol that carries block storage over TCP on port 3260. When recovering files, Azure Backup's script mounts recovery point disks as local volumes using it.
- NFS
Network File System, a file-sharing protocol from the Unix world, available on Azure Files, Azure NetApp Files and Blob Storage (as NFSv3).
- vSAN
VMware's software-defined storage, which combines local devices across a cluster's ESX hosts into one shared datastore. Available as OSA or ESA, VCF can use it as principal storage.
- vMotion
Moves a running VM to another host with no downtime; its storage counterpart, Storage vMotion, relocates the files between datastores instead.
Related terms
- Distributed port group
Configures settings like teaming, VLAN, port binding and security for VMkernel adapters and VMs that connect to it, applied identically on all hosts joined to the vSphere Distributed Switch it lives on.
- network pool
Subnets defined in SDDC Manager for one layer 2 domain. Hosts joining a VCF domain get static IPs from it automatically for their vMotion and vSAN/NFS/iSCSI VMkernel adapters.
- pktcap-uw
Command-line packet capture and tracing for ESX, able to tap the host's networking path at various points such as a physical NIC, a switch port or a VMkernel adapter.
- Provisioning traffic
Traffic generated when VMs are cloned, cold-migrated or have snapshots migrated, NFC transfers included, treated by the VMkernel as its own system traffic type. Since vSphere 9.0, Network I/O Control can set aside bandwidth for it so it does not crowd out management traffic.
- PSA
Multipathing on ESX is organised by this VMkernel framework, which sits above NMP, HPP and any multipathing plug-ins supplied by third parties and coordinates them.
- vMotion network
Carries live-migration traffic between hosts, each using a VMkernel adapter enabled for vMotion; ideally kept separate from other traffic.