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vcsim features
Interacting with vcsim using the vSphere SOAP and REST APIs as you would a real vCenter covers the majority of vcsim use cases. In this document we cover additional features that are specific to vcsim.
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
The vm.customize
command can be used to set many (but not all) guest properties, using the same APIs as you would against a real vCenter.
Example:
% govc vm.power -off DC0_H0_VM1
% govc vm.customize -vm DC0_H0_VM1 -name fourtythree -ip 10.0.0.43
% govc vm.power -on DC0_H0_VM1
% govc object.collect -s vm/DC0_H0_VM1 guest.ipAddress guest.hostName
10.0.0.43
fourtythree
% govc vm.ip DC0_H0_VM1
10.0.0.43
Certain VirtualMachine properties cannot be modified using API methods in a real vCenter environment. Such fields can be populated in vcsim using VirtualMachineConfigSpec.ExtraConfig entries with a SET. prefix. Example:
% govc object.collect -s vm/DC0_H0_VM0 overallStatus
green
% govc vm.change -vm DC0_H0_VM0 -e SET.overallStatus=red
% govc object.collect -s vm/DC0_H0_VM0 overallStatus
red
The following example has the same effect as using the vm.customize
command above:
% 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
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
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
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
Sometimes, especially when debugging software, it can be useful to introduce delays to simulate network latency or a poorly performing vCenter. There are three command line options for dealing with delays.
Adds a constant delay (expressed in milliseconds) to every call.
Example:
% vcsim -delay 100
Adds a specified delay to individual methods. If both -method-delay
and
-delay
are specified, they are added together.
Example:
% vcsim -method-delay PowerOnVM_Task:100,PowerOffVM_Task:50
Specifies a jitter, i.e. a random value added to or subtracted from the delay. It is specified as a Coefficient of Variation, which is the same as the standard deviation divided by the mean. A reasonable starting value is 0.5, as it gives a nice variation without extreme outliers.
Example:
% vcsim -delay-jitter 0.5