As described in previous post “How to run Ubuntu 18.04 in docker container ?” once you have the docker image running for first time using,
$ sudo docker run -it 56def654ec22
Note: You don’t need to run this command always and for one docker instance this can be once in a lifetime of this instance and then just run “docker start CONTAINER_ID” to start the docker after you reboot the machine.
you will get an console and you can see the docker container ID getting created using below command,
$ sudo docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
97f8cfdb23d8 56def654ec22 "/bin/bash" 59 seconds ago Up 54 seconds angry_ishizaka
so, here every time you exit and run the docker using command “docker run -it IMAGE ID” , you will get new container ID, but since we want to keep our server as optimsed as possible in terms of resource usage, its always better to create container only once and work with the same container afterwords..
So, once you have exited the docker container first time, you can see the all current docker containers using command,
$ sudo docker ps -a
$ sudo docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
49db5136dac8 56def654ec22 "/bin/bash" 3 minutes ago Up 3 minutes distracted_hamilton
Now, when you want to work with same container again for next times, just start the container using below command,
$ sudo docker exec -i -t 49db5136dac8 bash
root@49db5136dac8:/#
Note: If you have rebooted your machine, then before running above command, You will need to start the docker instance as, “docker start CONTAINER ID “
$ sudo docker start 49db5136dac8
and then run the docker exec command,
$ sudo docker exec -i -t 49db5136dac8 bash
and stop the same container using, “docker stop CONTAINER ID “
$ sudo docker stop 49db5136dac8