vcsim

vcsim - A vCenter and ESXi API based simulator

This package implements a vSphere Web Services (SOAP) SDK endpoint intended for testing consumers of the API. While the mock framework is written in the Go language, it can be used by any language that can talk to the vSphere API.

Installation

Docker

The official vcsim Docker images are built from this Dockerfile.

Binaries

You can find prebuilt vcsim binaries on the releases page.

You can download and install a binary locally like this:

# extract vcsim binary to /usr/local/bin
# note: the "tar" command must run with root permissions
curl -L -o - https://github.com/vmware/govmomi/releases/latest/download/vcsim_$(uname -s)_$(uname -m).tar.gz | tar -C /usr/local/bin -xvzf - vcsim

Source

Install via go install

To build vcsim from source, first install the Go toolchain. You can then install the latest vcsim from Github using:

go install github.com/vmware/govmomi/vcsim@latest
$GOPATH/bin/vcsim -h

Note: govmomi and its binaries use Go modules, i.e. explicitly setting GOPATH is not required anymore. To inject build variables (see details below) used by vcsim version, GOFLAGS can be defined and are honored by go get.

⚠️ Make sure $GOPATH/bin is in your PATH to use the version installed from source.

Install via goreleaser

You can also build vcsim following our release process using goreleaser (requires Go toolchain). This will ensure that build time variables are correctly injected. Build (linker) flags and injection are defined in .goreleaser.yaml and automatically set as GOFLAGS when building with goreleaser.

Install goreleaser as per the installation instructions, then:

git clone https://github.com/vmware/govmomi.git
cd govmomi

# pick a tag (>=v0.25.0)
RELEASE=v0.25.0

git checkout ${RELEASE}

# build for the host OS/ARCH, otherwise omit --single-target
# binaries are placed in respective subdirectories in ./dist/
goreleaser build --clean --single-target

Usage

The vcsim program by default creates a vCenter model with a datacenter, hosts, cluster, resource pools, networks and a datastore. The naming is similar to that of the original vcsim mode that was included with vCenter. The number of resources can be increased or decreased using the various resource type flags. Resources can also be created and removed using the API. In fact, vcsim itself uses the vSphere API generate its inventory.

$ vcsim -h # pruned to model type flags used in the Examples section
Usage of vcsim:
  -E string
        Output vcsim variables to the given fifo or stdout (default "-")
  -api-version string
        API version (default "6.5")
  -app int
        Number of virtual apps per compute resource
  -autostart
        Autostart model created VMs (default true)
  -cluster int
        Number of clusters (default 1)
  -dc int
        Number of datacenters (default 1)
  -delay int
        Method response delay across all methods
  -delay-jitter float
        Delay jitter coefficient of variation (tip: 0.5 is a good starting value)
  -ds int
        Number of local datastores (default 1)
  -esx
        Simulate standalone ESX
  -folder int
        Number of folders
  -host int
        Number of hosts per cluster (default 3)
  -l string
        Listen address for vcsim (default "127.0.0.1:8989")
  -load string
        Load model from directory
  -method-delay string
        Delay per method on the form 'method1:delay1,method2:delay2...'
  -nsx int
        Number of NSX backed opaque networks
  -password string
        Login password for vcsim (any password allowed by default)
  -pg int
        Number of port groups (default 1)
  -pg-nsx int
        Number of NSX backed port groups
  -pod int
        Number of storage pods per datacenter
  -pool int
        Number of resource pools per compute resource
  -standalone-host int
        Number of standalone hosts (default 1)
  -stdinexit
        Press any key to exit
  -tls
        Enable TLS (default true)
  -tlscert string
        Path to TLS certificate file
  -tlskey string
        Path to TLS key file
  -trace
        Trace SOAP to -trace-file
  -trace-file string
        Trace output file (defaults to stderr)
  -tunnel int
        SDK tunnel port (default -1)
  -username string
        Login username for vcsim (any username allowed by default)
  -vm int
        Number of virtual machines per resource pool (default 2)

Version Information

To print detailed (build) information for vcsim run: vcsim version.

Examples

The following examples illustrate how vcsim flags can be used to change the generated inventory. Each example assumes GOVC_URL is set to vcsim's default listen address:

export GOVC_URL=https://user:pass@127.0.0.1:8989

Default vCenter inventory

$ $GOPATH/bin/vcsim

$ govc find -l
Folder                       /
Datacenter                   /DC0
Folder                       /DC0/vm
VirtualMachine               /DC0/vm/DC0_H0_VM0
VirtualMachine               /DC0/vm/DC0_H0_VM1
VirtualMachine               /DC0/vm/DC0_C0_RP0_VM0
VirtualMachine               /DC0/vm/DC0_C0_RP0_VM1
Folder                       /DC0/host
ComputeResource              /DC0/host/DC0_H0
HostSystem                   /DC0/host/DC0_H0/DC0_H0
ResourcePool                 /DC0/host/DC0_H0/Resources
ClusterComputeResource       /DC0/host/DC0_C0
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H0
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H1
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H2
ResourcePool                 /DC0/host/DC0_C0/Resources
Folder                       /DC0/datastore
Datastore                    /DC0/datastore/LocalDS_0
Folder                       /DC0/network
Network                      /DC0/network/VM Network
DistributedVirtualSwitch     /DC0/network/DVS0
DistributedVirtualPortgroup  /DC0/network/DVS0-DVUplinks-9
DistributedVirtualPortgroup  /DC0/network/DC0_DVPG0

Default standalone ESX inventory

With the -esx flag, vcsim behaves as a standalone ESX host without any vCenter specific features.

$ $GOPATH/vcsim -esx

$ govc find
/
/ha-datacenter
/ha-datacenter/vm
/ha-datacenter/vm/ha-host_VM0
/ha-datacenter/vm/ha-host_VM1
/ha-datacenter/host
/ha-datacenter/host/localhost.localdomain
/ha-datacenter/host/localhost.localdomain/localhost.localdomain
/ha-datacenter/host/localhost.localdomain/Resources
/ha-datacenter/datastore
/ha-datacenter/datastore/LocalDS_0
/ha-datacenter/network
/ha-datacenter/network/VM Network

Customizing inventory

Model flags can be specified to increase or decrease the generated inventory.

$ vcsim -dc 2 -folder 1 -ds 4 -pod 1 -nsx 2 -pool 2 -app 1

$ govc find -l
Folder                       /
Datacenter                   /DC0
Folder                       /DC0/vm
VirtualMachine               /DC0/vm/DC0_H0_VM0
VirtualMachine               /DC0/vm/DC0_H0_VM1
VirtualMachine               /DC0/vm/DC0_C0_RP0_VM0
VirtualMachine               /DC0/vm/DC0_C0_RP0_VM1
VirtualMachine               /DC0/vm/DC0_C0_APP0_VM0
VirtualMachine               /DC0/vm/DC0_C0_APP0_VM1
Folder                       /DC0/host
ComputeResource              /DC0/host/DC0_H0
HostSystem                   /DC0/host/DC0_H0/DC0_H0
ResourcePool                 /DC0/host/DC0_H0/Resources
ClusterComputeResource       /DC0/host/DC0_C0
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H0
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H1
HostSystem                   /DC0/host/DC0_C0/DC0_C0_H2
ResourcePool                 /DC0/host/DC0_C0/Resources
ResourcePool                 /DC0/host/DC0_C0/Resources/DC0_C0_RP1
ResourcePool                 /DC0/host/DC0_C0/Resources/DC0_C0_RP2
VirtualApp                   /DC0/host/DC0_C0/Resources/DC0_C0_APP0
Folder                       /DC0/datastore
StoragePod                   /DC0/datastore/DC0_POD0
Datastore                    /DC0/datastore/LocalDS_0
Datastore                    /DC0/datastore/LocalDS_1
Datastore                    /DC0/datastore/LocalDS_2
Datastore                    /DC0/datastore/LocalDS_3
Folder                       /DC0/network
Network                      /DC0/network/VM Network
DistributedVirtualSwitch     /DC0/network/DVS0
DistributedVirtualPortgroup  /DC0/network/DVS0-DVUplinks-10
DistributedVirtualPortgroup  /DC0/network/DC0_DVPG0
OpaqueNetwork                /DC0/network/DC0_NSX0
OpaqueNetwork                /DC0/network/DC0_NSX1
Folder                       /F0
Datacenter                   /F0/DC1
Folder                       /F0/DC1/vm
Folder                       /F0/DC1/vm/F0
VirtualMachine               /F0/DC1/vm/F0/DC1_H0_VM0
VirtualMachine               /F0/DC1/vm/F0/DC1_H0_VM1
VirtualMachine               /F0/DC1/vm/F0/DC1_C0_RP0_VM0
VirtualMachine               /F0/DC1/vm/F0/DC1_C0_RP0_VM1
VirtualMachine               /F0/DC1/vm/F0/DC1_C0_APP0_VM0
VirtualMachine               /F0/DC1/vm/F0/DC1_C0_APP0_VM1
Folder                       /F0/DC1/host
Folder                       /F0/DC1/host/F0
ComputeResource              /F0/DC1/host/F0/DC1_H0
HostSystem                   /F0/DC1/host/F0/DC1_H0/DC1_H0
ResourcePool                 /F0/DC1/host/F0/DC1_H0/Resources
ClusterComputeResource       /F0/DC1/host/F0/DC1_C0
HostSystem                   /F0/DC1/host/F0/DC1_C0/DC1_C0_H0
HostSystem                   /F0/DC1/host/F0/DC1_C0/DC1_C0_H1
HostSystem                   /F0/DC1/host/F0/DC1_C0/DC1_C0_H2
ResourcePool                 /F0/DC1/host/F0/DC1_C0/Resources
ResourcePool                 /F0/DC1/host/F0/DC1_C0/Resources/DC1_C0_RP1
ResourcePool                 /F0/DC1/host/F0/DC1_C0/Resources/DC1_C0_RP2
VirtualApp                   /F0/DC1/host/F0/DC1_C0/Resources/DC1_C0_APP0
Folder                       /F0/DC1/datastore
StoragePod                   /F0/DC1/datastore/DC1_POD0
Folder                       /F0/DC1/datastore/F0
Datastore                    /F0/DC1/datastore/F0/LocalDS_0
Datastore                    /F0/DC1/datastore/F0/LocalDS_1
Datastore                    /F0/DC1/datastore/F0/LocalDS_2
Datastore                    /F0/DC1/datastore/F0/LocalDS_3
Folder                       /F0/DC1/network
Network                      /F0/DC1/network/VM Network
Folder                       /F0/DC1/network/F0
DistributedVirtualSwitch     /F0/DC1/network/F0/DVS0
DistributedVirtualPortgroup  /F0/DC1/network/F0/DVS0-DVUplinks-69
DistributedVirtualPortgroup  /F0/DC1/network/F0/DC1_DVPG0
OpaqueNetwork                /F0/DC1/network/F0/DC1_NSX0
OpaqueNetwork                /F0/DC1/network/F0/DC1_NSX1

Create yourself a Datastore cluster:

$ govc object.mv /F0/DC0/datastore/F0/LocalDS_[123] /DC1/datastore/DC0_POD0

$ govc find -l /DC0/datastore
Folder      /DC0/datastore
StoragePod  /DC0/datastore/DC0_POD0
Datastore   /DC0/datastore/LocalDS_0
Datastore   /DC0/datastore/DC0_POD0/LocalDS_1
Datastore   /DC0/datastore/DC0_POD0/LocalDS_2
Datastore   /DC0/datastore/DC0_POD0/LocalDS_3

Starting with empty inventory

The model flags when set to 0 can be used to turn off generation of any type. With Datacenter generation turned off, the inventory will be empty:

$ $GOPATH/vcsim -dc 0
$ govc find
/

You can create your own inventory using the API or govc:

$ govc datacenter.create godc

$ govc cluster.create gocluster

$ govc cluster.add -hostname gohost1 -username user -password pass -noverify

$ govc datastore.create -type local -name gostore -path /tmp gocluster/*

$ govc vm.create -ds gostore -cluster gocluster govm1

$ govc find -l
Folder                  /
Datacenter              /godc
Folder                  /godc/vm
VirtualMachine          /godc/vm/govm1
Folder                  /godc/host
ClusterComputeResource  /godc/host/gocluster
HostSystem              /godc/host/gocluster/gohost1
ResourcePool            /godc/host/gocluster/Resources
Folder                  /godc/datastore
Datastore               /godc/datastore/gostore
Folder                  /godc/network
Network                 /godc/network/VM Network

Generated inventory names

The generated names include a prefix per-type and integer suffix per-instance. See the simulator.Model documentation for a complete list of type prefixes. For example, the name DC0_C1_RP0_VM6 is composed of:

VMs with Clusters include the ResourcePool in their name, while VMs in standalone hosts include the host name instead. For example, the name DC0_H0_VM1 is composed of:

Supported methods

The simulator supports a subset of API methods. However, the generated govmomi code includes all types and methods defined in the vmodl, which can be used to implement any method documented in the VMware vSphere API Reference.

To see the list of supported methods:

curl -sk https://user:pass@127.0.0.1:8989/about

Listen address

The default vcsim listen address is 127.0.0.1:8989. Use the -l flag to listen on another address:

vcsim -l 10.118.69.224:8989 # specific address

vcsim -l :8989 # any address

When given a port value of 0, an unused port will be chosen. You can then source the GOVC_URL from another process, for example:

govc_sim_env=$TMPDIR/vcsim-$(uuidgen)

mkfifo $govc_sim_env

vcsim -l 127.0.0.1:0 -E $govc_sim_env &

eval "$(cat $govc_sim_env)"

# ... run tests ...

kill $GOVC_SIM_PID
rm -f $govc_sim_env

Tests written in Go can also use the simulator package directly, rather than the vcsim binary.

Feature Details

For more details on vcsim features, see the project wiki.

Projects using vcsim

• VMware VIC Engine

• Kubernetes

• Ansible

• Telegraf

Blog posts

• Beginning vCenter Server simulation with vcsim by Abhijeet Kasurde

• vCenter & ESXi API based simulator by William Lam

• vCenter Simulator Docker Container by Brian Bunke

• Using govc with vcsim in Kubernetes by Michael Gasch

Related projects

• LocalStack

License

vcsim is available under the Apache 2 license.

Name

Pronounced "v-c-sim", short for "vCenter Simulator"