CentOS image is not running?

Question

I downloaded centos base image executed in background as daemon and then tired to get in the terminal and couldn't get in.

My Host is Ubuntu 16.04.

Here are the steps I executed:

Host OS Version Ubuntu16.04

 root@jim-Ubuntu1504:/home/jim/web# lsb_release -a No LSB modules are
 available. Distributor ID: Ubuntu Description:    Ubuntu 16.04 LTS
 Release:        16.04 Codename:       xenial
 root@jim-Ubuntu1504:/home/jim/web#

Started docker by following commands

root@jim-Ubuntu1504:/home/jim/web# docker run -d --name=my_centos centos
Unable to find image 'centos:latest' locally
latest: Pulling from library/centos
a3ed95caeb02: Pull complete 
da71393503ec: Pull complete 
Digest: sha256:1a62cd7c773dd5c6cf08e2e28596f6fcc99bd97e38c9b324163e0da90ed27562
Status: Downloaded newer image for centos:latest
63f4b8fce1bd44253bb420436da3ad5b8f532b253fc9e74ff52ad1b2f9844251
root@jim-Ubuntu1504:/home/jim/web# docker exec -i -t my_centos bash
Error response from daemon: Container 63f4b8fce1bd44253bb420436da3ad5b8f532b253fc9e74ff52ad1b2f9844251 is not running

No idea why it is exiting

root@jim-Ubuntu1504:/home/jim/web# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                      PORTS               NAMES
63f4b8fce1bd        centos              "/bin/bash"              18 minutes ago      Exited (0) 18 minutes ago                       my_centos
f0ca8b9f4fa5        nginx               "nginx -g 'daemon off"   23 minutes ago      Up 23 minutes               80/tcp, 443/tcp     my_nginxtemp
bb9ab4958c33        nginx               "nginx -g 'daemon off"   About an hour ago   Up About an hour            80/tcp, 443/tcp     boring_aryabhata
886d174f641d        nginx               "nginx -g 'daemon off"   2 hours ago         Up 2 hours                  80/tcp, 443/tcp     mad_fermat
root@jim-Ubuntu1504:/home/jim/web# 

Started the container but no idea why it is exiting

root@jim-Ubuntu1504:/home/jim/web# docker start 63f4b8fce1bd
63f4b8fce1bd
root@jim-Ubuntu1504:/home/jim/web# docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS               NAMES
63f4b8fce1bd        centos              "/bin/bash"              26 minutes ago      Exited (0) 2 seconds ago                       my_centos
f0ca8b9f4fa5        nginx               "nginx -g 'daemon off"   30 minutes ago      Up 30 minutes              80/tcp, 443/tcp     my_nginxtemp
bb9ab4958c33        nginx               "nginx -g 'daemon off"   About an hour ago   Up About an hour           80/tcp, 443/tcp     boring_aryabhata
886d174f641d        nginx               "nginx -g 'daemon off"   2 hours ago         Up 2 hours                 80/tcp, 443/tcp     mad_fermat
root@jim-Ubuntu1504:/home/jim/web# docker exec -i -t my_centos bash
Error response from daemon: Container 63f4b8fce1bd44253bb420436da3ad5b8f532b253fc9e74ff52ad1b2f9844251 is not running
root@jim-Ubuntu1504:/home/jim/web# 

PS: Can someone disable the restriction to post once every 90 mins ??? Learning has to be spontaneous and interactive.

Answer 1

You are looking for running centos container in detached mode. Try the following...

sudo docker run -d -it centos

Answer 2

if you look at the Dockerfile of the latest image of CentOS, you will notice the last line, from here:

CMD ["/bin/bash"]

So you launch a container that has a shell, it exists and that is all.

Try:

docker run -it --name=my_centos centos sleep infinity

or any variant.

By the way, when you do

root@jim-Ubuntu1504:/home/jim/web# docker exec -i -t my_centos bash

you suppose that your container is running, which here, is not.

Check with:

docker ps -a --filter="name=my_centos"

that your container is up.

Answer 3

You have to run the image in interactive mode to be able to connect to it.

docker run -it centos

The -it instructs Docker to allocate a pseudo-TTY connected to the container’s stdin; creating an interactive bash shell in the container.

You can expect this after running that command.

docker@default:~$ docker run -it centos [root@0c3c7d59b91c /]#