How to create LXD image from an existing snapshot

Create LXD image from an existing snapshot.

Create an instance.

$ lxc launch ubuntu:groovy jenkins

Update it using bash, ansible, or other automation utility.

$ lxc exec jenkins bash

Create snapshot.

$ lxc snapshot jenkins jenkins_snapshot_20200404

Create an image and set desired properties.

$ lxc publish jenkins/jenkins_snapshot_20200404 --alias local_jenkins description="Jenkins application"

List images.

$ lxc image list

+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
|     ALIAS     | FINGERPRINT  | PUBLIC |                 DESCRIPTION                 | ARCHITECTURE |   TYPE    |   SIZE    |         UPLOAD DATE          |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
| local_jenkins | 643f21fc40b0 | no     | Jenkins application                         | x86_64       | CONTAINER | 1607.19MB | Apr 4, 2021 at 3:04pm (UTC)  |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
|               | 6ac59eac2988 | no     | ubuntu 20.10 amd64 (release) (20210325)     | x86_64       | CONTAINER | 364.59MB  | Mar 29, 2021 at 9:28pm (UTC) |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
|               | 46701fa2d99c | no     | ubuntu 20.04 LTS amd64 (release) (20210325) | x86_64       | CONTAINER | 360.90MB  | Mar 28, 2021 at 2:18pm (UTC) |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+

Inspect created image.

$ lxc image info local_jenkins

Fingerprint: 643f21fc40b0bd4393a0542ccf408841aaf6ee5133f7469dbf6d87df1fb50c5b
Size: 1607.19MB
Architecture: x86_64
Type: container
Public: no
Timestamps:
    Created: 2021/04/04 15:04 UTC
    Uploaded: 2021/04/04 15:04 UTC
    Expires: never
    Last used: never
Properties:
    description: Jenkins application
Aliases:
    - local_jenkins
Cached: no
Auto update: disabled
Profiles:
    - default

Export image.

$ lxc image export local_jenkins local_jenkins

Inspect created archive file and share it.

$ ls -lh local_jenkins.tar.gz 

-rw-rw-r-- 1 milosz milosz 1.6G Apr  4 15:05 local_jenkins.tar.gz

Now, you can import it on a different server.

$ lxc image import local_jenkins.tar.gz --alias local_jenkins

Display images.

$ lxc image list

+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
|     ALIAS     | FINGERPRINT  | PUBLIC |                 DESCRIPTION                 | ARCHITECTURE |   TYPE    |   SIZE    |         UPLOAD DATE          |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
| local_jenkins | 643f21fc40b0 | no     | Jenkins application                         | x86_64       | CONTAINER | 1607.19MB | Apr 4, 2021 at 3:06pm (UTC)  |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+
|               | 46701fa2d99c | no     | ubuntu 20.04 LTS amd64 (release) (20210325) | x86_64       | CONTAINER | 360.90MB  | Mar 28, 2021 at 2:58pm (UTC) |
+---------------+--------------+--------+---------------------------------------------+--------------+-----------+-----------+------------------------------+

Launch an instance using this image.

$ lxc launch local_jenkins jenkins