Running An Instance In OpenStack

.

Introduction

The instance is a virtual machine that run inside the cloud. So when we say run an instance, we mean run an instance of a specific virtual machine image. The virtual machine image (or simply the image) is a single file that contains a bootable operating system with cloud support. The package “Cloud-init” is installed in the virtual machine image to enable instance activation and initialization. You can NOT use a classic image. You must use “Cloud-Aware” image.

The image format must be supported by the hypervisor. So see your hypervisor and image format compatibility. Here you can find descriptions of different formats.

Upload A Virtual Machine Image

In the dashborad, go to “Project” tab on the left-side navigation menu and click on “Images”. Then click on “Create Image” to upload the image. You will get this dialog box:

Screenshot from 2015-02-22 12:05:50

Here you can find explanations of dialog box fieldsCurrently only images available via an HTTP URL are supported. So i chose the “Image Location” as an “Image Source” and the “Image Location” is: http://download.fedoraproject.org/pub/fedora/linux/releases/21/Cloud/Images/i386/Fedora-Cloud-Base-20141203-21.i386.qcow2

The selected image format “qcow2” which is commonly used with the KVM (default hypervisor). The size of image file is nearly 169 MB. It takes some time for image to be uploaded. Here you can find set of cloud ready images, copy the link location and paste it in the dialog box above in the “Image Location” field.

After the image has been uploaded successfully, you will be here:

Screenshot from 2015-02-22 12:25:00Enable SSH On Your Default Security Group

Click the “Project” tab on the left-side navigation menu. Then click on “Access & Security”. Under the “Security Groups” tab, Select the “default” security group. Click on the “Manage Rules” button, you will get this table of rules:

Screenshot from 2015-02-22 13:01:39Click on “Add Rule”, Enter the “22” in the “Port” field:

Screenshot from 2015-02-22 13:05:51

 Then click the “Add” button. The rule will be added and then SSH can be used.

Screenshot from 2015-02-22 13:09:56

If you create a new security group and you want to apply its rules to an instance, be aware to select it when you launch the instance so the rules of the new security group will be applied to the new instance (launch the instance in specific security group).

Create OR Import Key Pair

To access the instance through SSH, we need to create or import kay pair. Click on “Access & Security” on the left-side navigation menu, and then click on the tab “Key Pairs”.

To create a key pair, click on “Create Key Pair”. The key pair (private an public keys) will be generated. The public key will be registered and the the private key must be saved privately after download.

The public key is injected into the instance using “Cloud-init” package on boot.

Screenshot from 2015-02-22 13:47:53

Screenshot from 2015-02-22 14:05:31The option “Import Key pair” will prompt you to provide a name and a public key.

Launch The Virtual Machine

Go to the uploaded image and click on “Launch” button. You will get this dialog box:

Screenshot from 2015-03-15 18:13:35In the resulting dialog box and under “Details” tab, you can specify number of parameters like the “Instance Name” and “Flavor” (defines the hardware resources of the instance). Check also the configuration under other tabs (Access & Security, Networking, Post-Creation, and Advanced Options). Then click the “Launch” button to ask the Compute service (Compute Node) to launch an instance with your specified parameters.

Now The instance is created. Click “Instances” on the left-side navigation menu, to see the instantiated instances.

Connecting To The Instance Console

In the figure above, click on “Associate Floating IP” on the right side to associate “floating IP” to your instance. Both the floating and the internal IP addresses will be listed in the “IP Address” column for your instance. The internal IP address of the instance is a private IP address used to reach other OpenStack instances. The floating IP address is used to access the instance from other machines in your network (Private IP address) or from the internet (Public IP address). It is called floating because you can associate it to an instance and disassociate it so it is movable (It can move to another instance).

# ssh -i /home/binan/Downloads/binankeypair.pem  fedora@Floating-IP-Address

“fedora” is the default user for fedora instances.

Also you can access the instance console  via the dashboard or by specifying the network namespace where your instance resides:

# ip netns exec qrouter-f96c719a-56e9-4b52-b2cb-da326fc1a429 ssh -i /home/binan/Downloads/binankeypair.pem  fedora@Local-IP-Address

where the “qrouter-f96c719a-56e9-4b52-b2cb-da326fc1a429” is the namespace name.

Congratulation, You have successfully created an instance of a specific virtual machine image and you can SSH to your instance.


More Information


Advertisements

One comment on “Running An Instance In OpenStack

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s