Merge branch 'instance-shelving' into 'master'

feature - Creating Instance shelving tutorial

See merge request !46

topics/compute/openstack/docs/technical-reference/brno-site/instance-shelving.md

+---
+
+title: Instance shelving
+search:
+  exclude: false
+---
+
+# Instance shelving 
+
+[OpenStack instance shelving](https://docs.openstack.org/ocata/user-guide/cli-stop-and-start-an-instance.html#shelve-and-unshelve-an-instance) allows you to stop an instance without having it consume any cloud hypervisor resources. A shelved instance will be retained as a bootable instance, as well as its resources assigned, such as an IP address in distributed storage, for a configurable amount of time, and then deleted. This is useful as part of an instance life cycle process or to conserve resources.
+
+## What instance shelving does ?
+
+It creates a snapshot of the state of **running** instance, containing instance data and resource allocations. Data in memory is **not** retained, however. The instance then goes into **Shelved Offloaded** state and shuts itself down. Once the instance is required again, it is **unshelved** and restored to a running state with all resources and data.
+
+## How to shelve your instance ?
+
+There are two possible ways to shelve your instance:
+
+1. Via GUI
+2. Via command line
+
+### GUI shelving
+
+Go into your instance list, located at the left menu bar on the path **Project>Compute>Instances**. Then you select the **Actions** menu located on the right side of the listed instances. After that, choose the **running** instance to shelve and select from the **Actions** menu the option **Shelve Instance** and click it.
+
+![](/compute/openstack/images/instance-shelving/shelving.png)
+
+Once the shelving process is finished, you can check that the instance is in the status **Shelved Offloaded** and its power state is **Shut Down**.
+
+![](/compute/openstack/images/instance-shelving/shelving_status.png)
+
+Now the instance is offloaded from the computational host, and you can use resources from the shelved instance.
+
+Once you are finished and wish to restore your instance into a running state, go and select from **Actions** menu the option **Unshelve Instance** and click it.
+ 
+ ![](/compute/openstack/images/instance-shelving/unshelving_status.png)
+
+### CLI shelving
+
+
+Select an instance in **Active** status from the list of instances you wish to shelve.
+
+```
+# openstack server list --status active 
+
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+| ID                                   | Name         | Status | Networks                             | Image | Flavor        |
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+| 59f02d12-**************-f02d7731d13c | vm-to-shelve | ACTIVE | ********************                 |       | standard.tiny |
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+```
+
+Use the following command to shelve that instance.
+
+```
+openstack server shelve {NAME_OF_INSTANCE|ID_OF_INSTANCE}
+```
+After that, you can check that the selected instance is no longer in **Active** status. It is in **Shelved Offloaded**. Resources were freed and are now at your disposal and ready to use.
+
+```
+# openstack server shelve vm-to-shelve
+
+# openstack server list --status active 
+
+# openstack server list
+
++--------------------------------------+--------------+-------------------+--------------------------------+-------+---------------+
+| ID                                   | Name         | Status            | Networks                       | Image | Flavor        |
++--------------------------------------+--------------+-------------------+--------------------------------+-------+---------------+
+| 59f02d12-**************-f02d7731d13c | vm-to-shelve | SHELVED_OFFLOADED | *******************            |       | standard.tiny |
++--------------------------------------+--------------+-------------------+--------------------------------+-------+---------------+
+
+```
+
+After you are finished with your work, you can easily restore the shelved instance by running this command:
+
+```
+openstack server unshelve {NAME_OF_INSTANCE|ID_OF_INSTANCE}
+```
+
+ Once the command is finished, you can check if your instance is restored and in a running state.
+
+```
+# openstack server unshelve vm-to-shelve
+
+# openstack server list --status active 
+
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+| ID                                   | Name         | Status | Networks                             | Image | Flavor        |
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+| 59f02d12-**************-f02d7731d13c | vm-to-shelve | ACTIVE | ********************                 |       | standard.tiny |
++--------------------------------------+--------------+--------+--------------------------------------+-------+---------------+
+```
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