Instances are virtual machines that run inside the cloud. You can launch an instance from the following sources:

• Images uploaded to the Image service.
• Image that you have copied to a persistent volume. The instance launches from the volume, which is provided by the cinder-volume API through iSCSI.
• Instance snapshot that you took.

Launch an instance

1. Log in to the dashboard.
2. Select the appropriate project from the drop down menu at the top left.
3. On the Project tab, open the Compute tab and click Instances category.
   The dashboard shows the instances with its name, its private and floating IP addresses, size, status, task, power state, and so on.
4. Click Launch Instance.
5. In the Launch Instance dialog box (fig), specify the following values:

Details tab

Instance Name: Assign a name to the virtual machine.

Description: You can assign a brief description of the virtual machine.

Availability Zone: By default, this value is set to the availability zone given by the cloud provider (for example, us-west or apac-south). For some cases, it could be nova.

Count: To launch multiple instances, enter a value greater than 1. The default is 1.

Source tab

In the drop down menu Select Boot Source your options are:

• Boot from Image: using this option, you can select the image from the list. You can also choose to use persistent storage by creating a new volume.
• Boot from Instance Snapshot: using this option, you can select the snapshot from the list. You can also choose to use persistent storage by creating a new volume.
• Boot from Volume: using this option, you can select the volume from the list. It does not create a new volume.
• Boot from Volume Snapshot: using this option, you can select Volume Snapshot from the list. It creates a new volume to persist instance data.

Click the Delete Volume on Instance Delete option to delete the volume on deleting the instance. This option is allowed when the volume is created by default or by your choice (i.e. if the Create New Volume option is set to yes).

Flavor tab

Flavor: Specify the size of the instance to launch.

Note: The flavor is selected based on the size of the image selected for launching an instance. For example, while creating an image, if you have entered the value in the Minimum RAM (MB) field as 2048, then on selecting the image, the default flavor is m1.small.

Networks tab

Networks: To add a network to the instance, click the ↑ in the Available field.

Network Ports tab

Ports: Activate the ports that you want to assign to the instance.

Security Groups tab

Security Groups: Activate the security groups that you want to assign to the instance. Security groups are a kind of cloud firewall that define which incoming network traffic is forwarded to instances. If you have not created any security groups, you can assign only the default security group to the instance.

Key Pair tab

Key Pair: Specify a key pair. If the image uses a static root password or a static key set (neither is recommended), you do not need to provide a key pair to launch the instance.

Configuration tab

Customization Script Source: Specify a customization script that runs after your instance launches. Here you can find an example of cloud config.

Metadata tab

Available Metadata: Add Metadata items to your instance.

Click Launch Instance. The instance starts on a compute node in the cloud.

 Connect to your instance by using SSH

To use SSH to connect to your instance, use the downloaded Key Pair file.

1. Activate the VPN if you are outside the CNAF offices.
2. Take note of the location of your private key, or go to the folder where it is located.
3. Remember the FloatingIP address for your instance.

4. Use the SSH command to make a secure connection to the instance. For example:
   

   $ ssh -i <key_path>/<key_name> -l <operating_system_users> <FloatingIP>

   
   

5. At the prompt, type yes.

Manage an instance

1. Log in to the dashboard.
2. Select the appropriate project from the drop down menu at the top left.
3. On the Project tab, open the Compute tab and click Instances category.
4. By clicking the menu list of an instance, you can perform various actions:
   1. You can resize or rebuild an instance.
   2. You can also choose to view the instance console log, edit instance or the security groups.
   3. Depending on the current state of the instance, you can pause, resume, suspend, soft or hard reboot, or terminate it.

Let's see some examples.

Create an instance snapshot

A snapshot of a Virtual Machine is an image which preserves the disk state of that running instance. Snapshots can be used e.g. to backup your instances, or to migrate your instances to another cloud.

1. Log in to the dashboard.
2. Select the appropriate project from the drop down menu at the top left.
3. On the Project tab, open the Compute tab and click the Instances category.
4. Select the instance from which to create a snapshot.
5. In the actions column, click Create Snapshot.
6. In the Create Snapshot dialog box, enter a name for the snapshot, and click Create Snapshot.

The Images category shows the instance snapshot. To launch an instance from the snapshot, select the snapshot and click Launch. Proceed with launching an instance.

Stopping and Starting Instance

Pause Instance/Unpause Instance allows for temporary suspension of the VM. The VM is kept in memory but it is not allocated any CPU time.
Suspend Instance/Resume Instance stores the VM onto disk and recovers it later. This is faster than stop/start and the VM returns to the status is was when the suspend was performed as opposed to a new boot cycle.

Resizing Instance

If the size of a virtual machine needs to be changed, such as adding more memory or cores, this can be done using the resize operation. Using resize, you can select a new flavor for your virtual machine. The operation will reboot the virtual machine and might take several minutes of downtime, so this operation should be planned as it will lead to application downtime.

To resize an instance:

• Detach any attached volume as described in the next chapter.
• Select the Compute tab menu and then Resize Instance option on the actions column.
• In the Resize Instance box (fig) select the desired flavor.
• Click Resize.
• After the new flavor has been selected, the status will become resize or migrating.
• The status will change after several minutes to Confirm or Revert Resize/Migrate. You may need to refresh the web browser page to reflect the new status.
• Select Confirm Resize/Migrate if you wish to change the instance to the new configuration.

The status will then change to Active once completed.

Track usage for instances

You can track usage for instances for each project. You can track costs per month by showing meters like number of vCPUs, disks, RAM, and uptime for all your instances.

1. Log in to the dashboard.
2. Select the appropriate project from the drop down menu at the top left.
3. On the Project tab, open the Compute tab and click Overview category.
4. To query the instance usage for a month, select a month and click Submit (at the bottom of the page).
5. To download a summary, click Download CSV Summary.