Ubuntu image won't start on Centos

Docker Engine General
1

Hello,

A few weeks ago I’ve created a customized docker Ubuntu (14.04) image with some ansible and Galaxy Roles.

The main idea was to share my ansible tools with others.
the image was built and exported on a Ubuntu machine.

One my collegues has a Centos 7 VM with docker
centos-release-7-5.1804.el7.centos.2.x86_64

docker version
Client:
Version: 17.05.0-ce
API version: 1.29
Go version: go1.7.5
Git commit: 89658be
Built: Thu May 4 22:06:25 2017
OS/Arch: linux/amd64

Server:
Version: 17.05.0-ce
API version: 1.29 (minimum version 1.12)
Go version: go1.7.5
Git commit: 89658be
Built: Thu May 4 22:06:25 2017
OS/Arch: linux/amd64
Experimental: false

We’ve been able to import the image.

Creating the container using the “docker run -it --name ansiblecontainer -v /usr/playbooks:/playbooks -e TZ=“Europe/Paris” -u root 76619dba82ae”

will give me this type of output:

“docker: Error response from daemon: No command specified.”
I noticed the container was created after even with some error.
but It’s not possible To start the container : “docker start 60cf9ff092c7” will give me
“Error response from daemon: linux spec user: unable to find user root: no matching entries in passwd file
Error: failed to start containers: 60cf9ff092c7”

Please help,

Regards

2

If your image does not have a default command set to run on startup (in your Dockerfile) you have to provide one yourself on the command line. You could add ‘/bin/bash’ and try.

docker run -it --name ansiblecontainer -v /usr/playbooks:/playbooks -e TZ=“Europe/Paris” -u root 76619dba82ae /bin/bash

3

Hello sillydockerid,

Thanks for your reply, I tried the following command

“[root@xxxxxx ~]# docker run -it --name ansibletest -v /usr/playbooks:/playbooks -e TZ=“Europe/Paris” -u root 76619dba82ae /bin/bash”

It will give me the following error

"docker: Error response from daemon: linux spec user: unable to find user root: no matching entries in passwd file. "

and will create the docker container

[root@xxxxx ~]# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
5a91eeba4afd 76619dba82ae “/bin/bash” 7 seconds ago Created ansibletest

I’m not able to start the container.

Regards

4

Hi dbenny,

The/etc/passwd file in your image probably does not contain an entry for root. Did you modify that file in you image build?

Can you run this command:

docker run -it --name ansibletest -v /usr/playbooks:/playbooks -e TZ=“Europe/Paris” 76619dba82ae cat /etc/passwd

It will show you the contents of the /etc/passwd file in the image.

5

Hi sillydockerid,

I didn’t modify the file, the command will give the following

[root@server ~]# docker run -it --name ansibletest10 -v /usr/playbooks:/playbooks -e TZ=“Europe/Paris” 76619dba82ae cat /etc/passwd

docker: Error response from daemon: oci runtime error: container_linux.go:247: starting container process caused “exec: “cat”: executable file not found in $PATH”.

Regards

6

Can you run any of the below?
docker run -it 76619dba82ae /bin/bash
or
docker run -it 76619dba82ae /bin/sh

If all of the above fail can you perhaps share your Dockerfile?

Does the container run on your own machine?

7

When in the original post you say “export” and “import” the image…what commands, exactly, did you run on which machines?

8

Hello David,

I would generally use this type of command

docker export 7c5ab332c34d | /opt/test/ubuntu-pyez-final.tar

where 7c5ab332c34d is the container ID of the customized Ubuntu image.

I would import the image using

cat ubuntu-pyez-final.tar | docker import - ubuntu-pyez:new

Maybe I’m wrong on the method and I should do it again?

Thanks