Remote OpenStack Instances using Gophercloud (using neutron networking)
2020-03-16T22:24:21Z
Introduction:
Following program uses gophercloud library to spin instances in OpenStack environment. This program uses Neutron Networking. This program will also assign FloatingIP to very first instance.
Requirments:
An already running OpenStack environment. You can get a free playground for OpenStack to play with at http://trystack.org/. At minimum you need following information.
Auth URL : It may look like this http://10.0.2.15:5000/v2.0
UserName : This is a user in OpenStack. default: admin
Password : This is an API password. API password can be different from user password.
Tenant : This is more like a project/Account or Organization. A tenant can have multiple users associated with it.. default: admin
Region : Default region is set to RegionOne.In trystack.org this information can be found at https://x86.trystack.org/dashboard/project/access_and_security/ and click on Download OpenStack RC file. Contents of RC file will have all the required information.
Following is the source code.
package main
import (
"crypto/rand"
"flag"
"fmt"
"github.com/rackspace/gophercloud"
"github.com/rackspace/gophercloud/openstack"
"github.com/rackspace/gophercloud/openstack/compute/v2/flavors"
"github.com/rackspace/gophercloud/openstack/compute/v2/images"
"github.com/rackspace/gophercloud/openstack/compute/v2/servers"
"github.com/rackspace/gophercloud/openstack/networking/v2/extensions/layer3/floatingips"
"github.com/rackspace/gophercloud/openstack/networking/v2/networks"
"github.com/rackspace/gophercloud/openstack/networking/v2/ports"
"os"
"strconv"
)
func checkErrorAndExit(err error) {
if err != nil {
fmt.Printf("Error: %v\n", err.Error())
os.Exit(3)
}
}
func checkErrorAndContinue(err error) {
if err != nil {
fmt.Printf("Error: %v\n", err.Error())
}
}
func generateRandomString() string {
b := make([]byte, 8)
_, err := rand.Read(b)
checkErrorAndExit(err)
name := fmt.Sprintf("%X", b[0:4])
return name
}
func main() {
user := flag.String("user", "admin", "OS Username")
pass := flag.String("password", "acf0d596fbb44b1d", "Password")
authUrl := flag.String("authurl", "http://10.0.2.15:5000/v2.0", "AUTH URL")
tenant := flag.String("tenant", "admin", "Tenant Name")
region := flag.String("region", "RegionOne", "Region for VM")
defaultRun := flag.Bool("runwithdefaultvalues", false, "Use this flag to use default values")
image := flag.String("image", "cirros", "Image to be used")
flavor := flag.String("flavor", "m1.tiny", "Size of VM")
private_network := flag.String("private_network", "private", "private network for VM")
public_network := flag.String("public_network", "public", "public network for VM")
securityGroup := flag.String("securitygroup", "default", "Security Group for VM")
hostNamePrefix := flag.String("hostnameprefix", generateRandomString(), "Hostname Prefix. default: randomly generated.")
total := flag.String("total", "5", "Total number of instances")
flag.Parse()
os.Setenv("OS_USERNAME", *user)
os.Setenv("OS_PASSWORD", *pass)
os.Setenv("OS_AUTH_URL", *authUrl)
os.Setenv("OS_TENANT_NAME", *tenant)
os.Setenv("OS_REGION_NAME", *region)
if flag.NFlag() == 0 {
flag.PrintDefaults()
os.Exit(1)
} else if *defaultRun == true {
fmt.Println("Creating VMs: ")
} else {
fmt.Println("Creating VMs: ")
}
authOpts, err := openstack.AuthOptionsFromEnv()
checkErrorAndExit(err)
provider, err := openstack.AuthenticatedClient(authOpts)
checkErrorAndExit(err)
otherOpts := gophercloud.EndpointOpts{Region: *region}
client, err := openstack.NewComputeV2(provider, otherOpts)
imageID, err := images.IDFromName(client, *image)
checkErrorAndExit(err)
flavorID, err := flavors.IDFromName(client, *flavor)
checkErrorAndExit(err)
netClient, err := openstack.NewNetworkV2(provider, gophercloud.EndpointOpts{Name: "neutron", Region: *region})
checkErrorAndExit(err)
privateNetworkID, err := networks.IDFromName(netClient, *private_network)
checkErrorAndExit(err)
publicNetworkID, err := networks.IDFromName(netClient, *public_network)
checkErrorAndExit(err)
portOpts := ports.CreateOpts{NetworkID: privateNetworkID,
AdminStateUp: ports.Up}
netport, err := ports.Create(netClient, portOpts).Extract()
checkErrorAndExit(err)
network1 := servers.Network{UUID: privateNetworkID}
network2 := servers.Network{Port: netport.ID}
allNetworks := []servers.Network{network1}
allPortNetworks := []servers.Network{network2}
fmt.Printf("Obtaining free floating IP: ")
floatingIPOpts := floatingips.CreateOpts{FloatingNetworkID: publicNetworkID,
PortID: netport.ID}
floatingIP, err := floatingips.Create(netClient, floatingIPOpts).Extract()
checkErrorAndExit(err)
fmt.Printf("%s found.\n", floatingIP.FloatingIP)
noOfInstances, err := strconv.Atoi(*total)
checkErrorAndExit(err)
for i := 1; i <= noOfInstances; i++ {
networks := allNetworks
if i == 1 {
networks = allPortNetworks
} else {
networks = allNetworks
}
vmName := *hostNamePrefix + strconv.Itoa(i)
serverCreateOpts := servers.CreateOpts{Name: vmName,
FlavorRef: flavorID,
ImageRef: imageID,
Networks: networks,
UserData: []byte{},
SecurityGroups: []string{*securityGroup}}
_, err := servers.Create(client, serverCreateOpts).Extract()
checkErrorAndContinue(err)
fmt.Printf("%s VM creation request sent successfully.\n Details: { flavor=%s, image=%s, network=%s, sec_group=%s }\n", vmName, *flavor, *image, *private_network, *securityGroup)
fmt.Println("===================================")
}
}Create a file launchOpenStackInstances.go and populate it with above contents. Use following steps on Linux and MacOS to compile/build it.
- Make sure GO Lang compiler is installed.
- Place go source code in a directory. (most likely home directory)
mkdir MYGO
export GOPATH=$HOME/MYGO
go get github.com/rackspace/gophercloud
go build launchOpenStackInstances.go- An executable with name launchOpenStackInstances will be there .
Below is the sample run:
# ./launchOpenStackInstances.go -authurl=http://10.1.0.10:5000/v2.0 -flavor=m1.tiny -image=cirros -private_network=private_network -public_network=public_network -user=admin -password=106d84bf40fb4413 -total=2
Creating VMs:
Obtaining free floating IP: 10.1.0.159 found.
5F52A0801 VM creation request sent successfully.
Details: { flavor=m1.tiny, image=cirros, network=private_network, sec_group=default }
===================================
5F52A0802 VM creation request sent successfully.
Details: { flavor=m1.tiny, image=cirros, network=private_network, sec_group=default }
===================================Observation 1: This program uses Neutron Networking.
Observation 2: Compare this program with the program using Nova Networking. There is no infinite loop required to assign floatingIP in this program.
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