vcsim features

vcsim Features

Interacting with vcsim using the vSphere SOAP and REST APIs covers the majority of use cases. In this document we cover additional features that are specific to vcsim.

Authentication

By default, vcsim allows any non-empty username and password for authentication via the SessionManager.Login() method. To require a specific combination:

% vcsim -username root -password my-password
export GOVC_URL=https://root:[email protected]:8989/sdk GOVC_SIM_PID=22732

Go example

Injecting Virtual Machine properties

Certain VirtualMachine properties cannot be modified using API methods in a real vCenter environment. For example, the VirtualMachine.Guest field is populated by data from vmware-tools rather than the API. Such fields can be populated in vcsim using VirtualMachineConfigSpec.ExtraConfig entries with a SET. prefix.

% govc vm.change -vm DC0_H0_VM0 -e SET.guest.ipAddress=10.0.0.42 -e SET.guest.hostName=fourtytwo

% govc object.collect -s vm/DC0_H0_VM0 guest.ipAddress guest.hostName
10.0.0.42
fourtytwo

% govc vm.ip DC0_H0_VM0
10.0.0.42

Go example

Containers as VMs

For the use case of VirtualMachine interaction outside of the API, a container can be tied to the lifecycle of a vcsim VM. The VM guest field is populated with the container's IP address and MAC address. And VirtualMachine lifecycle methods are mapped to the container:

VM State	VM Method	Docker command
poweredOff	PowerOn	start
suspended	PowerOn	unpause
poweredOn	PowerOff	stop
poweredOn	Suspend	pause
poweredOn	Reset	stop ; start
poweredOff	Destroy	rm -f

To use this feature, add a RUN.container key to the VirtualMachineConfigSpec.ExtraConfig field, with a value of the args to pass to docker run. If there is more than 1 argument, the list must be json encoded.

Example:

% govc vm.power -off DC0_H0_VM0
Powering off VirtualMachine:vm-53... OK

% govc vm.change -vm DC0_H0_VM0 -e RUN.container=nginx

% govc vm.power -on DC0_H0_VM0
Powering on VirtualMachine:vm-53... OK

% docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' DC0_H0_VM0
172.17.0.2

% govc vm.ip DC0_H0_VM0
172.17.0.2

% curl -s http://172.17.0.2 | grep title
<title>Welcome to nginx!</title>

% docker inspect -f '{{.State.Status}}' DC0_H0_VM0
running

% govc vm.power -off DC0_H0_VM0
Powering off VirtualMachine:vm-53... OK

% docker inspect -f '{{.State.Status}}' DC0_H0_VM0
exited

% govc vm.destroy DC0_H0_VM0

% docker inspect -f '{{.State.Status}}' DC0_H0_VM0
Error: No such object: DC0_H0_VM0

Go example

Record and Playback

The govc object.save command can be used to save the inventory of running vCenter, an ESXi host or a vcsim instance. By default, the entire inventory is saved including the ServiceInstance, all Managed Objects and their properties. Each object is saved to a .xml file in ObjectContent format. The object files are saved inside a directory, which defaults to ./vcsim-$hostname and can be overridden using the -d flag.

% govc object.save -u user:pass@my-vcenter -d my-vcenter
Saved 164 total objects to "my-vcenter", including:
ClusterComputeResource: 2
Datastore: 6
DistributedVirtualPortgroup: 2
EnvironmentBrowser: 2
Folder: 20
HostDatastoreBrowser: 6
HostSystem: 4
Network: 3
OpaqueNetwork: 30
ResourcePool: 15
VirtualMachine: 29

The vcsim -load flag will populate vcsim with the saved inventory, rather than vcsim's own built-in/default inventory.

Example:

% vcsim -load my-vcenter &

% export GOVC_URL=https://user:[email protected]:8989/sdk

% govc find / -type ClusterComputeResource | wc -l
2

% govc find / -type Datastore | wc -l
6

Modifying saved inventory

The properties withing the saved object files can be manually modified to cover cases that the API does not. For example, HostSystem hardware properties cannot be changed using the API.

% vcsim &
export GOVC_URL=https://user:[email protected]:8989/sdk GOVC_SIM_PID=16237

% export GOVC_URL=https://user:[email protected]:8989/sdk GOVC_SIM_PID=16237

% govc object.collect -type HostSystem / summary.hardware.memorySize
HostSystem:host-20  summary.hardware.memorySize  int64  4294430720
HostSystem:host-32  summary.hardware.memorySize  int64  4294430720
HostSystem:host-39  summary.hardware.memorySize  int64  4294430720
HostSystem:host-46  summary.hardware.memorySize  int64  4294430720

% govc object.save -d vcsim-host-math
Saved 69 total objects to "vcsim-host-math", including:
DistributedVirtualPortgroup: 2
EnvironmentBrowser: 2
Folder: 5
HostSystem: 4
ResourcePool: 2
VirtualMachine: 4

% kill $GOVC_SIM_PID

% xmlstarlet ed -L -u '//propSet[name="summary"]//hardware/memorySize' -v 8588861440 vcsim-host-math/*host-20.xml

% vcsim -load ./vcsim-host-math &

% govc object.collect -type HostSystem / summary.hardware.memorySize
HostSystem:host-20  summary.hardware.memorySize  int64  8588861440 # doubled the memory of this host
HostSystem:host-32  summary.hardware.memorySize  int64  4294430720
HostSystem:host-39  summary.hardware.memorySize  int64  4294430720
HostSystem:host-46  summary.hardware.memorySize  int64  4294430720