For what reason can the container in docker not start?

Question

Docker

I installed the ubuntu server, as well as the docker, then with the command sudo docker run -d ubuntu installed the container. Now I enter the command sudo docker ps and in response I get only this line

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES

please tell me why is that?

Answer 1

The container starts and immediately closes.
Because by default, the command is executed there /bin/bash, which, without a terminal, immediately ends execution.
You run the container in daemon mode (key -d)
If there were not bashsome long-running command, mysqld or nginx, everything would work longer.
Probably, you need to start the container and "be" in its shell:
docker run -it --rm ubuntu

• -iinteractive mode
  
• -tconnects a virtual terminal
  
• --rmwill delete the container as soon as you exit it
  

Here are two options to start Ubuntu so that the container remains hanging:
docker run -d ubuntu tail -f /dev/null- here is a dummy command that will run indefinitely;
docker run -t -d ubuntu- a virtual terminal is connected here and bash will not crash, but will remain running.