⁠8.8. Creating an Instance Snapshot

You can create a snapshot of a running instance. You may wish to do this for backup purposes or for creating a base image to create other instances from, after applying some customization.
As an example, you may want every instance to have a user called projectuser. Create that user in the virtual machine and then create a snapshot. That snapshot can be used as the base for new instances.
Start by applying some sort of customization to the virtual machine. These commands could be used to create a user and set its password: 
vm$ useradd projectuser
vm$ passwd projectuser
Now create a snapshot of that running instance: 
$ nova image-create <instanceid> "snapshot 1"
The snapshot is complete when its status in nova image-list changes from SAVING to ACTIVE. 
$ nova image-list
+--------------------------------------+------------+--------+--------+
|                  ID                  |    Name    | Status | Server |
+--------------------------------------+------------+--------+--------+
| 17a34b8e-c573-48d6-920c-b4b450172b41 | RHEL 6.2   | ACTIVE |        |
| 84420f08-1e4b-499a-837a-5c6c1b9903d0 | snapshot 1 | SAVING | ...... |
+--------------------------------------+------------+--------+--------+
$ nova image-list
+--------------------------------------+------------+--------+--------+
|                  ID                  |    Name    | Status | Server |
+--------------------------------------+------------+--------+--------+
| 17a34b8e-c573-48d6-920c-b4b450172b41 | RHEL 6.2   | ACTIVE |        |
| 84420f08-1e4b-499a-837a-5c6c1b9903d0 | snapshot 1 | ACTIVE | ...... |
+--------------------------------------+------------+--------+--------+
Once the snapshot's status is active, you can start up a new instance using this image: 
$ nova boot --image 84420f08-1e4b-499a-837a-5c6c1b9903d0 --flavor 2 --key_name oskey \
  snapshot-instance
+------------------------+--------------------------------------+
|        Property        |                Value                 |
+------------------------+--------------------------------------+
| OS-DCF:diskConfig      | MANUAL                               |
| OS-EXT-STS:power_state | 0                                    |
| OS-EXT-STS:task_state  | scheduling                           |
| OS-EXT-STS:vm_state    | building                             |
| accessIPv4             |                                      |
| accessIPv6             |                                      |
| adminPass              | QASX3r8jKzVd                         |
| config_drive           |                                      |
| created                | 2012-05-18T13:49:07Z                 |
| flavor                 | m1.small                             |
| hostId                 |                                      |
| id                     | ac9e6a9f-58c3-47c3-9b4c-485aa421b8a8 |
| image                  | snapshot 1                           |
| key_name               | oskey                                |
| metadata               | {}                                   |
| name                   | snapshot-instance                    |
| progress               | 0                                    |
| status                 | BUILD                                |
| tenant_id              | 05816b0106994f95a83b913d4ff995eb     |
| updated                | 2012-05-18T13:49:08Z                 |
| user_id                | 1d59c0bfef9b4ea9ab63e2a058e68ae0     |
+------------------------+--------------------------------------+
	$ nova list
+--------------------------------------+-------------------+--------+------------------+
|                  ID                  |        Name       | Status |     Networks     |
+--------------------------------------+-------------------+--------+------------------+
| 0e4011a4-3128-4674-ab16-dd1b7ecc126e | rhel              | ACTIVE | demonet=10.0.0.2 |
| ac9e6a9f-58c3-47c3-9b4c-485aa421b8a8 | snapshot-instance | BUILD  | demonet=10.0.0.4 |
| b8d5c952-f2fc-4556-83f2-57c79378d867 | rhel2             | ACTIVE | demonet=10.0.0.3 |
+--------------------------------------+-------------------+--------+------------------+
Finally, test that the new instance contains the expected customizations made earlier in this exercise. If you followed the example, the instance should have a user named projectuser. 
$ ssh -i oskey.priv root@10.0.0.4
vm$ su projectuser
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