I have a docker image that at the end launch this script:
# Start the server
CMD [ "bash", "/app/start.sh"]
And then my script start.sh
# Create ssh user
useradd -m -d /home/${SSH_MASTER_USER} -G ssh ${SSH_MASTER_USER} -s /bin/bash
echo "${SSH_MASTER_USER}:${SSH_MASTER_PASS}" | chpasswd
echo 'PATH="/usr/local/bin:/usr/bin:/bin:/usr/sbin"' >> /home/${SSH_MASTER_USER}/.profile
And I keep getting this error:
useradd: Permission denied.
useradd: cannot lock /etc/passwd; try again later.
If run with sudo it says:
sudo: no tty present and no askpass program specified
Tried to fix it like this:
sudo -S useradd -m -d /home/${SSH_MASTER_USER} -G ssh ${SSH_MASTER_USER} -s /bin/bash
But now is asking me for a password, but there is not password...
my base image is using root.
so i am adding appuser and installing sudo like this:
RUN adduser --disabled-password --gecos "" appuser
RUN apt-get update
RUN apt-get install -y sudo
RUN echo "appuser ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/appuser && chmod 0440 /etc/sudoers.d/appuser
Later on when you ready to use new user for all commands:
USER appuser:appuser
that is it, now appuser which is going to be user by default can use sudo without password.
I have solved by adding my existing user to the sudo group:
RUN echo "myUser ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/docker && chmod 0440 /etc/sudoers.d/docker
then the:
sudo -S useradd -m -d /home/${SSH_MASTER_USER} -G ssh ${SSH_MASTER_USER} -s /bin/bash
worked without password
I am trying build cassandra docker image using alpine based os. on the container run process i am getting permission related issue, as i am running as cassandra user. i am unable to run sudo and switch my user cassandra as sudo user. below is my sample docker file, shows only sudo user related logic--
FROM alpine:latest
RUN apk --no-cache update \
&& apk --no-cache add sudo
copy run.sh /usr/local/
RUN addgroup -S cassandra && adduser -S cassandra -G cassandra
RUN chown -R cassandra:cassandra /home/cassandra/
RUN echo 'cassandra ALL=(ALL) /bin/su' >> /etc/sudoers
USER cassandra
ENTRYPOINT [ "sh","/usr/local/run.sh"]
after login to container i am unable to perform any sudo related task.
First thing, you do not need to assign root permission to newly created user, which kill purpose of the user.
So you do not need to change user to root user, you can run command in the running container with root user.
docker exec -it --user root mycontainer sh
or in Dockerfile
USER root
# Run root operation here
# Change user back to cassandra
USER cassandra
Btw you can create root user using below commands
Dockerfile
RUN adduser -D $USER && mkdir -p /etc/sudoers.d \
&& echo "$USER ALL=(ALL) NOPASSWD: ALL" > /etc/sudoers.d/$USER \
&& chmod 0440 /etc/sudoers.d/$USER
USER $USER
WORKDIR $HOME
RUN whoami
RUN sudo whoami
Build Output
Step 9/11 : RUN whoami
---> Running in d52065213d2d
default
Removing intermediate container d52065213d2d
---> c1b526ea8342
Step 10/11 : RUN sudo whoami
---> Running in 5f4ddd11a5f2
root
I wanted to restrict access of su to others but not to my deploy user. So I followed below steps. As you can see su is owned by deploy already but still I am not able to access it.
my docker file is like below:
FROM alpine:3.8
RUN set -ex \
&& addgroup -g 1000 deploy \
&& adduser -D -u 1000 -G deploy -s /bin/sh deploy \
&& chown root:deploy /bin/su \
&& chmod u+rws,g+rws,o-rwx /bin/su
USER deploy:nobody
Inside container when I execute below commands:
/var/www/ $ ls -al /bin/su
-rwsrws--- 1 root deploy 36560 May 19 11:19 /bin/su
/var/www/ $ su -h
sh: su: Permission denied
Note: While I switch from root to deploy like below it works.
docker exec -it --user root alpine sh
/var/www/ # su deploy
/var/www/ $ su -h
My bad, I figured out myself. As my dockerfile runs as USER deploy:nobody so wherever I run docker exec -it alpine sh, the container run as group nobody but the /bin/su is only permitted to root:deploy. :)
I don't want to be root inside a docker container.
But I have to modify some files which belong to root in a script.
I want to use sudo for this.
This is my docker file:
FROM ubuntu:16.04
RUN apt-get update
RUN apt-get install -y curl wget python openssh-server sudo
RUN mkdir /grader
RUN mkdir /grader/week1
RUN mkdir /grader/week1/assignment2
ADD executeGrader.sh /grader/
RUN groupadd -g 1000 coursera
RUN useradd -g 1000 -u 1000 --shell /bin/bash coursera
RUN usermod -a -G sudo coursera
RUN mkdir /home/coursera
RUN chown coursera:coursera /home/coursera
RUN echo "StrictHostKeyChecking no" >> /etc/ssh/ssh_config
RUN echo "coursera ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers
RUN chmod 777 /etc/hostname
USER coursera
EXPOSE 8080
EXPOSE 8081
ENTRYPOINT ["/grader/executeGrader.sh"]
executeGrader.sh contains this one:
#!/bin/bash
id
sudo -u root -H bash -c "hostname localhost"
But I get this one :/
>>docker run -h sdfsdfsdf323 -u 1000:1000 -P stackoverflow
uid=1000(coursera) gid=1000(coursera) groups=1000(coursera)
hostname: you must be root to change the host name
Any ideas?
Thanks for all your support, this one was finally working for me:
export temphostname=`hostname`
sudo su -c "echo 127.0.0.1 $temphostname >> /etc/hosts"
Normally, docker containers are run using the user root. I'd like to use a different user, which is no problem using docker's USER directive. But this user should be able to use sudo inside the container. This command is missing.
Here's a simple Dockerfile for this purpose:
FROM ubuntu:12.04
RUN useradd docker && echo "docker:docker" | chpasswd
RUN mkdir -p /home/docker && chown -R docker:docker /home/docker
USER docker
CMD /bin/bash
Running this container, I get logged in with user 'docker'. When I try to use sudo, the command isn't found. So I tried to install the sudo package inside my Dockerfile using
RUN apt-get install sudo
This results in Unable to locate package sudo
Just got it. As regan pointed out, I had to add the user to the sudoers group. But the main reason was I'd forgotten to update the repositories cache, so apt-get couldn't find the sudo package. It's working now. Here's the completed code:
FROM ubuntu:12.04
RUN apt-get update && \
apt-get -y install sudo
RUN useradd -m docker && echo "docker:docker" | chpasswd && adduser docker sudo
USER docker
CMD /bin/bash
When neither sudo nor apt-get is available in container, you can also jump into running container as root user using command
docker exec -u root -t -i container_id /bin/bash
The other answers didn't work for me. I kept searching and found a blog post that covered how a team was running non-root inside of a docker container.
Here's the TL;DR version:
RUN apt-get update \
&& apt-get install -y sudo
RUN adduser --disabled-password --gecos '' docker
RUN adduser docker sudo
RUN echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
USER docker
# this is where I was running into problems with the other approaches
RUN sudo apt-get update
I was using FROM node:9.3 for this, but I suspect that other similar container bases would work as well.
For anyone who has this issue with an already running container, and they don't necessarily want to rebuild, the following command connects to a running container with root privileges:
docker exec -ti -u root container_name bash
You can also connect using its ID, rather than its name, by finding it with:
docker ps -l
To save your changes so that they are still there when you next launch the container (or docker-compose cluster) - note that these changes would not be repeated if you rebuild from scratch:
docker commit container_id image_name
To roll back to a previous image version (warning: this deletes history rather than appends to the end, so to keep a reference to the current image, tag it first using the optional step):
docker history image_name
docker tag latest_image_id my_descriptive_tag_name # optional
docker tag desired_history_image_id image_name
To start a container that isn't running and connect as root:
docker run -ti -u root --entrypoint=/bin/bash image_id_or_name -s
To copy from a running container:
docker cp <containerId>:/file/path/within/container /host/path/target
To export a copy of the image:
docker save container | gzip > /dir/file.tar.gz
Which you can restore to another Docker install using:
gzcat /dir/file.tar.gz | docker load
It is much quicker but takes more space to not compress, using:
docker save container | dir/file.tar
And:
cat dir/file.tar | docker load
if you want to connect to container and install something
using apt-get
first as above answer from our brother "Tomáš Záluský"
docker exec -u root -t -i container_id /bin/bash
then try to
RUN apt-get update or apt-get 'anything you want'
it worked with me
hope it's useful for all
Unlike accepted answer, I use usermod instead.
Assume already logged-in as root in docker, and "fruit" is the new non-root username I want to add, simply run this commands:
apt update && apt install sudo
adduser fruit
usermod -aG sudo fruit
Remember to save image after update. Use docker ps to get current running docker's <CONTAINER ID> and <IMAGE>, then run docker commit -m "added sudo user" <CONTAINER ID> <IMAGE> to save docker image.
Then test with:
su fruit
sudo whoami
Or test by direct login(ensure save image first) as that non-root user when launch docker:
docker run -it --user fruit <IMAGE>
sudo whoami
You can use sudo -k to reset password prompt timestamp:
sudo whoami # No password prompt
sudo -k # Invalidates the user's cached credentials
sudo whoami # This will prompt for password
Here's how I setup a non-root user with the base image of ubuntu:18.04:
RUN \
groupadd -g 999 foo && useradd -u 999 -g foo -G sudo -m -s /bin/bash foo && \
sed -i /etc/sudoers -re 's/^%sudo.*/%sudo ALL=(ALL:ALL) NOPASSWD: ALL/g' && \
sed -i /etc/sudoers -re 's/^root.*/root ALL=(ALL:ALL) NOPASSWD: ALL/g' && \
sed -i /etc/sudoers -re 's/^#includedir.*/## **Removed the include directive** ##"/g' && \
echo "foo ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers && \
echo "Customized the sudoers file for passwordless access to the foo user!" && \
echo "foo user:"; su - foo -c id
What happens with the above code:
The user and group foo is created.
The user foo is added to the both the foo and sudo group.
The uid and gid is set to the value of 999.
The home directory is set to /home/foo.
The shell is set to /bin/bash.
The sed command does inline updates to the /etc/sudoers file to allow foo and root users passwordless access to the sudo group.
The sed command disables the #includedir directive that would allow any files in subdirectories to override these inline updates.
If SUDO or apt-get is not accessible inside the Container, You can use, below option in running container.
docker exec -u root -it f83b5c5bf413 ash
"f83b5c5bf413" is my container ID & here is working example from my terminal:
This may not work for all images, but some images contain a root user already, such as in the jupyterhub/singleuser image. With that image it's simply:
USER root
RUN sudo apt-get update
The main idea is that you need to create user that is a root user according to the container.
Main commands:
RUN echo "bot:bot" | chpasswd
RUN adduser bot sudo
the first sends the literal string bot:bot to chpasswd which creates the user bot with the password bot, chpasswd does:
The chpasswd command reads a list of user name and password pairs from standard input and uses this information to update a group of existing users. Each line is of the format:
user_name:password
By default the supplied password must be in clear-text, and is encrypted by chpasswd. Also the password age will be updated, if present.
The second command I assume adds the user bot as sudo.
Full docker container to play with:
FROM continuumio/miniconda3
# FROM --platform=linux/amd64 continuumio/miniconda3
MAINTAINER Brando Miranda "me#gmail.com"
RUN apt-get update \
&& apt-get install -y --no-install-recommends \
ssh \
git \
m4 \
libgmp-dev \
opam \
wget \
ca-certificates \
rsync \
strace \
gcc \
rlwrap \
sudo
# https://github.com/giampaolo/psutil/pull/2103
RUN useradd -m bot
# format for chpasswd user_name:password
RUN echo "bot:bot" | chpasswd
RUN adduser bot sudo
WORKDIR /home/bot
USER bot
#CMD /bin/bash
If you have a container running as root that runs a script (which you can't change) that needs access to the sudo command, you can simply create a new sudo script in your $PATH that calls the passed command.
e.g. In your Dockerfile:
RUN if type sudo 2>/dev/null; then \
echo "The sudo command already exists... Skipping."; \
else \
echo -e "#!/bin/sh\n\${#}" > /usr/sbin/sudo; \
chmod +x /usr/sbin/sudo; \
fi
An example Dockerfile for Centos7. In this example we add prod_user with privilege of sudo.
FROM centos:7
RUN yum -y update && yum clean all
RUN yum -y install openssh-server python3 sudo
RUN adduser -m prod_user && \
echo "MyPass*49?" | passwd prod_user --stdin && \
usermod -aG wheel prod_user && \
mkdir /home/prod_user/.ssh && \
chown prod_user:prod_user -R /home/prod_user/ && \
chmod 700 /home/prod_user/.ssh
RUN echo "prod_user ALL=(ALL) NOPASSWD: ALL" >> /etc/sudoers && \
echo "%wheel ALL=(ALL) ALL" >> /etc/sudoers
RUN echo "PasswordAuthentication yes" >> /etc/ssh/sshd_config
RUN systemctl enable sshd.service
VOLUME [ "/sys/fs/cgroup" ]
ENTRYPOINT ["/usr/sbin/init"]
There is no answer on how to do this on CentOS.
On Centos, you can add following to Dockerfile
RUN echo "user ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/user && \
chmod 0440 /etc/sudoers.d/user
I'm using an Ubuntu image, while using the docker desktop had faced this issue.
The following resolved the issue:
apt-get update
apt-get install sudo