To Export and Import Docker Container on Ubuntu 21.04

Introduction:

Docker is a platform as a service that delivers software in containers using OS-level virtualization, which allows you to build, test, and deploy applications quickly and easily.

Installation Procedure:

Step 1: Check the OS version by using below Command

root@linuxhelp:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 21.04
Release:	21.04
Codename:	hirsute

Step 2: Pull the Ubuntu Docker Image from Docker Hub BY using the below command

root@linuxhelp:~# docker pull ubuntu 
Using default tag: latest
latest: Pulling from library/ubuntu
08c01a0ec47e: Pull complete 
Digest: sha256:669e010b58baf5beb2836b253c1fd5768333f0d1dbcb834f7c07a4dc93f474be
Status: Downloaded newer image for ubuntu:latest
docker.io/library/ubuntu:latest

Step 3: List the Docker Images by using the below command

root@linuxhelp:~# docker images 
REPOSITORY   TAG       IMAGE ID       CREATED       SIZE
ubuntu       latest    54c9d81cbb44   13 days ago   72.8MB

Step 4: Run a Container from Ubuntu Docker Image by using the below command

root@linuxhelp:~# docker run -dit ubuntu 
8cae3796c71227f24e494526fa32b8b422eb9f842d5c94fa59fcb32001ff66de

Step 5: Check the Running Containers by using the below command

root@linuxhelp:~# docker ps 
CONTAINER ID   IMAGE     COMMAND   CREATED         STATUS         PORTS     NAMES
8cae3796c712   ubuntu    "bash"    8 seconds ago   Up 6 seconds             recursing_liskov

Step 6: Login to the Container Shell by using the below command

root@linuxhelp:~# docker exec -it recursing_liskov /bin/bash 

Step 7: Update the APT source List by using the below command

root@8cae3796c712:/# apt update 
Get:1 http://archive.ubuntu.com/ubuntu focal InRelease [265 kB]
Get:2 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Get:3 http://archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
Get:4 http://archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
Fetched 21.0 MB in 6s (3519 kB/s)                      
Reading package lists... Done
Building dependency tree       
Reading state information... Done
9 packages can be upgraded. Run 'apt list --upgradable' to see them.

Step 8: Install tree Package for testing purpose by using the below command

root@8cae3796c712:/# apt install tree -y 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following NEW packages will be installed:
  tree
0 upgraded, 1 newly installed, 0 to remove and 9 not upgraded.
Need to get 43.0 kB of archives.
After this operation, 115 kB of additional disk space will be used.
Get:1 http://archive.ubuntu.com/ubuntu focal/universe amd64 tree amd64 1.8.0-1 [43.0 kB]
Fetched 43.0 kB in 1s (70.7 kB/s)
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package tree.
(Reading database ... 4127 files and directories currently installed.)
Preparing to unpack .../tree_1.8.0-1_amd64.deb ...
Unpacking tree (1.8.0-1) ...
Setting up tree (1.8.0-1) ...

Step 9: Exit from the Container

root@8cae3796c712:/# exit 
exit

Step 10: Check the Running Containers by using the below command

root@linuxhelp:~# docker ps 
CONTAINER ID   IMAGE     COMMAND   CREATED              STATUS              PORTS     NAMES
8cae3796c712   ubuntu    "bash"    About a minute ago   Up About a minute             recursing_liskov

Step 11: Export the Running Container as tar file by using the below command

root@linuxhelp:~# docker export --output="tree.tar" recursing_liskov

Step 12: List the exported Image by using the below command

root@linuxhelp:~# ls -la 
total 106540
drwx------  4 root root      4096 Feb 16 04:34 .
drwxr-xr-x 20 root root      4096 Jan 15 02:16 ..
-rw-------  1 root root      1307 Jan 27 15:29 .bash_history
-rw-r--r--  1 root root      3106 Aug 15  2019 .bashrc
drwx------  3 root root      4096 Jan 19 23:33 .cache
-rw-r--r--  1 root root       161 Sep 16  2020 .profile
drwxr-xr-x  3 root root      4096 Jan 15 02:24 snap
-rw-------  1 root root 109064192 Feb 16 04:34 tree.tar
-rw-------  1 root root       767 Jan 15 02:19 .viminfo

Step 13: Import the Exported Container, The Exported Container is imported as Docker Image then need to run the Containers from the Image

root@linuxhelp:~# docker import tree.tar 
sha256:393a31a43b0904b8c0b6e2b7393bdc3806e4bdc0da81d183b85b8dbf3c50644d

Step 14: List the Docker Images by using the below command

root@linuxhelp:~# docker images 
REPOSITORY   TAG       IMAGE ID       CREATED         SIZE
<none>       <none>    393a31a43b09   6 minutes ago   107MB
ubuntu       latest    54c9d81cbb44   13 days ago     72.8MB

Step 15: Run a Container from the Imported Docker Image by using the below command

root@linuxhelp:~# docker run -it 393a31a43b09 /bin/bash 

Step 16: Check the Package installed before exporting by using the below command

root@fe34a3a35799:/# apt list --installed | grep tree 


WARNING: apt does not have a stable CLI interface. Use with caution in scripts.

tree/focal,now 1.8.0-1 amd64 [installed]

with this, the process of How to Export and Import Docker Container on Ubuntu 21.04 has comes to an end.