How to switch to root in Jenkins docker container? - docker

I have setup Jenkins server inside a docker container. The image I am using is docker pull jenkins. After that I connect to the container by docker exec -it b74d035352ec bash. The default user is jenkins but I can't switch to root and got below errors:
jenkins#b74d035352ec:/$ su -
su: must be run from a terminal
I got below error when running sudo:
$ sudo ls
We trust you have received the usual lecture from the local System
Administrator. It usually boils down to these three things:
#1) Respect the privacy of others.
#2) Think before you type.
#3) With great power comes great responsibility.
sudo: no tty present and no askpass program specified
Does anyone know how to solve the issue? I do need root permission on that container. Or should I install anything? I can build a new image from this image if needed.

You can only do that during build time, as described in the documentation.
FROM jenkins
# if we want to install via apt
USER root
RUN apt-get update && apt-get install -y ruby make more-thing-here
# drop back to the regular jenkins user - good practice
USER jenkins
So you have to build your own image to execute tasks as root user.

Simply you can login to the root account of the running jenkins-container as
docker exec -u 0 -it <container_id/container_name> /bin/bash
After logged in as root, you can switch to the jenkins account using su - jenkins if needed.

Related

Why is this Todo app build failing in Jenkins when deploying on AWS Linux using Docker file in WSL2?

So I was trying to deploy a simple CD pipeline using docker by ssh’ing into my AWS Linux EC2 instance in the WSL2 terminal. The job is failing every time returning the following error:
Started by user Navdeep Singh Running as SYSTEM Building on the
built-in node in workspace /var/lib/jenkins/workspace/todo-dev
[todo-dev] $ /bin/sh -xe /tmp/jenkins6737039323529850559.sh + cd
/home/ubuntu/project/django-todo /tmp/jenkins6737039323529850559.sh:
2: cd: can’t cd to /home/ubuntu/project/django-todo Build step
‘Execute shell’ marked build as failure Finished: FAILURE
DockerFile contents:
FROM python:3 RUN pip install django==3.2
COPY . .
RUN python manage.py migrate
CMD [“python”,“manage.py”,“runserver”,“0.0.0.0:8000”]
Everything goes fine. This error cd: can’t cd to /home/ubuntu/project/django-todo Build step ‘Execute shell’ marked build as failure Finished: FAILURE is not an actual.
Your agent Node is not online.
To fix the problem, find commands on your jenkins web page after an agent setup. You need to run those commands from your terminal. See the screenshot for more details.
Make sure that your jenkins public IP and node agent public IP are the same. If an error occurs, you need to run some commands on the terminal. This is not a real error.
this issue follow this step which i give you
For Agent--->
change your ip here(44.203.138.174:8080) to your EC2 ip
1.curl -sO http://44.203.138.174:8080/jnlpJars/agent.jar
2.java -jar agent.jar -jnlpUrl http://44.203.138.174:8080/manage/computer/todo%2Dagent/jenkins-agent.jnlp -secret beb62de0f81bfd06e4cd81d1b896d85d38f82b87b21ef8baef3389e651c9f72c -workDir "/home/ubuntu"
For JOb --->
sudo vi /etc/sudoers
then add this command below root access in sudoers file
jenkins ALL=(ALL) NOPASSWD: ALL
3.then goto the ubuntu directory using cd .. then run this codes
grep ^ubuntu /etc/group
id jenkins
sudo adduser jenkins ubuntu
grep ^ubuntu /etc/group
4.restart the jenkins relogin
sudo systemctl stop jenkins
then you good to go

Is there any way to run "pkexec" from a docker container?

I am trying to set up a Docker image (my Dockerfile is available here, sorry for the french README: https://framagit.org/Gwendal/firefox-icedtea-docker) with an old version of Firefox and an old version of Java to run an old Java applet to start a VPN. My image does work and successfully allows me to start the Java applet in Firefox.
Unfortunately, the said applet then tries to run the following command in the container (I've simply removed the --config part from the command as it does not matter here):
INFO: launching '/usr/bin/pkexec sh -c /usr/sbin/openvpn --config ...'
Then the applet exits silently with an error. While investigating, I've tried running a command with pkexec with the same Docker image, and it gives me this result:
$ sudo docker-compose run firefox pkexec /firefox/firefox-sdk/bin/firefox-bin -new-instance
**
ERROR:pkexec.c:719:main: assertion failed: (polkit_unix_process_get_start_time (POLKIT_UNIX_PROCESS (subject)) > 0)
But I don't know polkit at all and cannot understand this error.
EDIT: A more minimal way to reproduce the problem is with this Dockerfile:
FROM ubuntu:16.04
RUN apt-get update \
&& apt-get install -y policykit-1
And then run:
$ sudo docker build -t pkexec-test .
$ sudo docker run pkexec-test pkexec echo Hello
Which leads here again to:
ERROR:pkexec.c:719:main: assertion failed: (polkit_unix_process_get_start_time (POLKIT_UNIX_PROCESS (subject)) > 0)
Should I conclude that pkexec cannot work in a docker container? Or is there any way to make this command work?
Sidenote: I have no control whatsoever on the Java applet that I try to run, it is a horrible and very dated proprietary black box that I am supposed to use at work, for which I have no access to the source code, and that I must use as is.
I have solved my own problem by replacing pkexec by sudo in the docker image, and by allowing passwordless sudo.
Given an ubuntu docker image where a user called developer was created and configured with a USER statement, add these lines:
# Install sudo and make 'developer' a passwordless sudoer
RUN apt-get install sudo
ADD ./developersudo /etc/sudoers.d/developersudo
# Replacing pkexec by sudo
RUN rm /usr/bin/pkexec
RUN ln -s /usr/bin/sudo /usr/bin/pkexec
with the file developersudo containing:
developer ALL=(ALL) NOPASSWD:ALL
This replaces any call to pkexec made in a process running in the container, by a call to sudo without any password prompt, which works nicely.

docker login fails on a server with no X11 installed

I am trying to deploy a docker configuration with images on a private docker registry.
Now, every time I execute docker login registry.example.com, I get the following error message:
error getting credentials - err: exit status 1, out: Cannot autolaunch D-Bus without X11 $DISPLAY
The only solution I found for non-MacOS users was to run export $(dbus-launch) first, but that did not change anything.
I am running Ubuntu Server and tried with both the Ubuntu Docker package and the Docker-CE package.
How can I log in without an X11 session?
Looks like this is because it defaults to use the secretservice executable which seems to have some sort of X11 dependency for some reason. If you install and configure pass docker will use that instead which seems to solve the problem.
In a nutshell (from https://github.com/docker/compose/issues/6023)
sudo apt install gnupg2 pass
gpg2 --full-generate-key
This generates a you a gpg2 key. After that's done you can list it with
gpg2 -k
Copy the key id (from the line labelled [uid]) and do
pass init "whatever key id you have"
Now docker login should work.
There are a couple of bugs logged on launchpad regarding this:
https://bugs.launchpad.net/ubuntu/+source/golang-github-docker-docker-credential-helpers/+bug/1794307
https://bugs.launchpad.net/ubuntu/+source/docker-compose/+bug/1796119
This works: sudo apt remove golang-docker-credential-helpers
You can remove the offending package golang-docker-credential-helpers without removing all of docker-compose.
The following worked for me on a server without X11 installed:
dpkg -r --ignore-depends=golang-docker-credential-helpers golang-docker-credential-helpers
and then
echo 'foo' | docker login mydockerrepo.com -u dockeruser --password-stdin
Source:
bug reported in debian:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=910823#39
bug reported on ubuntu:
https://bugs.launchpad.net/ubuntu/+source/docker-compose/+bug/1796119
secretservice requires a GUI. You can use pass without a GUI.
Unfortunately, Docker's documentation on how to configure Docker Credential Helpers is quite lacking. Here's a comprehensive guide how to configure pass with Docker (tested with Ubuntu 18.04):
1. Install the Docker Credential Helper for pass
Find the url for the latest version of docker-credential-pass from https://github.com/docker/docker-credential-helpers/releases . For example:
# substitute with the latest version
url=https://github.com/docker/docker-credential-helpers/releases/download/v0.6.2/docker-credential-pass-v0.6.2-amd64.tar.gz
# download and untar the binary
wget $url
tar -xzvf $(basename $url)
# move the binary to a dir in your $PATH
sudo mv docker-credential-pass /usr/local/bin
# verify it works
docker-credential-pass list
2. Install and configure pass
apt install pass
# create a gpg2 key
gpg2 --gen-key
# if you have issues with lack of entropy, "apt install haveged" and try again
# create the password store using the gpg user id above
pass init $gpg_id
3. docker login
docker login
# You should not see any credentials stored in "auths" section.
# "credsStore": "pass" should have been automatically added.
# If the value is "secretservice", replace it with "pass".
cat ~/.docker/config.json
# verify credentials stored in `pass` store now
pass
There is a much easier answer than the ones already posted, which I found in a comment on https://github.com/docker/docker-credential-helpers/issues/105.
The solution is to rename docker-credential-secretservice out of the way
e.g: mv /usr/bin/docker-credential-secretservice /usr/bin/docker-credential-secretservice.broken
Once you do this, docker login works regardless of whether or not docker-compose is installed. No other package additions or removals are necessary.
I've resolved this issue by uninstalling docker-compose which was installed from Ubuntu repo and installing docker-compose by official instruction at https://docs.docker.com/compose/install/#install-compose
What helped me on Ubuntu 18.04 was:
Following the steps in #oberstet 's post and uninstalling the golang helper
Performing a login after the helper uninstall
Reinstalling docker via sudo apt-get install docker
Logging back in via sudo docker login

Yum update fails -Centos 7 - dockerbuild

I have frequently built docker container using centos 7 as base image. But now I am getting error when I run,
RUN yum update add \
bash \
&& rm -rfv /var/cache/apk/*
ERROR:
Loaded plugins: fastestmirror, ovl
One of the configured repositories failed (Unknown),
and yum doesn't have enough cached data to continue. At this point the only
safe thing yum can do is fail. There are a few ways to work "fix" this:
Contact the upstream for the repository and get them to fix the problem.
Reconfigure the baseurl/etc. for the repository, to point to a working
upstream. This is most often useful if you are using a newer
distribution release than is supported by the repository (and the
packages for the previous distribution release still work).
Run the command with the repository temporarily disabled
yum --disablerepo=<repoid> ...
Disable the repository permanently, so yum won't use it by default. Yum
will then just ignore the repository until you permanently enable it
again or use --enablerepo for temporary usage:
yum-config-manager --disable <repoid>
or
`subscription-manager repos --disable=<repoid>`
Configure the failing repository to be skipped, if it is unavailable.
Note that yum will try to contact the repo. when it runs most commands,
so will have to try and fail each time (and thus. yum will be be much
slower). If it is a very temporary problem though, this is often a nice
compromise:
yum-config-manager --save --setopt=<repoid>.skip_if_unavailable=true
Cannot find a valid baseurl for repo: base/7/x86_64 Could not retrieve
mirrorlist
http://mirrorlist.centos.org/?release=7&arch=x86_64&repo=os&infra=container
error was 14: curl#6 - "Could not resolve host: mirrorlist.centos.org;
Name or service not known" The command '/bin/sh -c yum update add
bash && rm -rfv /var/cache/apk/*' returned a non-zero code: 1
I also saw few resolutions to use "dhclient" but this error happens when i do docker-compose build.
I ran into this problem attempting to run the same Dockerfile, which fetched several software packages using yum, on two different platforms; one macOS, the other an Ubuntu 16.04-based Linux OS (elementaryOS Loki), both using the official packages from docker.com.
My theory is that the Linux package is just more restrictive out of the box, security-wise, than the macOS one. Maybe this is configurable with some kind of /etc/something config file, but I don't have the expertise with Docker to say for sure. EDIT: See my comment below.
What I can say is there was no additional configuration required for me on macOS (10.11 El Capitan); just docker build . worked fine, and yum processes from the Dockerfile were able to reach all the remote repositories.
In the Ubuntu-derived Linux distro, however, it was necessary to use
docker build --network host .
followed by
docker run -it --network host <image> <command>
when I wanted to run a process inside that image which required internet access.
This may be the case for other Debian-derived systems as well.
There are, of course, security considerations which need to be taken into account when allowing a long-running Docker container to communicate through the host network adapter, unrestricted, and one would do well to review the appropriate documentation in that regard.
My assumption is that for some reason network behavior in docker varies based on distribution.
Try to use:
docker run -d --net mybridge centos
or
docker network create -d bridge mybridge
docker run -d --net mybridge centos
It should start working. Or just edit /etc/hosts and add mirror address
Name: mirrorlist.centos.org
Address: 67.219.148.138
root cause of the issue is, container proxy settings were wrong. Just corrected the proxy settings at the below location and worked.
/root/.docker/config.json

How to test the container or image after docker build?

I have the following Dockerfile
############################################################
# Purpose : Dockerize Django App to be used in AWS EC2
# Django : 1.8.1
# OS : Ubuntu 14.04
# WebServer : nginx
# Database : Postgres inside RDS
# Python : 2.7
# VERSION : 0.1
############################################################
from ubuntu:14.04
maintainer Kim Stacks, kimcity#gmail.com
# make sure package repository is up to date
run echo "deb http://archive.ubuntu.com/ubuntu $(lsb_release -sc) main universe" > /etc/apt/sources.list
run apt-get update
# install python
# install nginx
Inside my VM, I did the following:
docker build -t ubuntu1404/djangoapp .
It is successful.
What do I do to run the docker image?
Where is the image or container?
I have already tried running
docker run ubuntu1404/djangoapp
Nothing happens.
What I see when I run docker images
root#vagrant-ubuntu-trusty-64:/var/virtual/Apps/DockerFiles/Django27InUbuntu# docker images
REPOSITORY TAG IMAGE ID CREATED VIRTUAL SIZE
ubuntu1404/djangoapp latest cfb161605c8e 10 minutes ago 198.3 MB
ubuntu 14.04 07f8e8c5e660 10 days ago 188.3 MB
hello-world latest 91c95931e552 3 weeks ago 910 B
When I run docker ps, nothing shows up
You have to give a command your container will have to process.
Example : sh
you could try :
docker run -ti yourimage sh
(-ti is used to keep a terminal open)
If you want to launch a daemon (like a server), you will have to enter something like :
docker run -d yourimage daemontolaunch
Use docker help run for more options.
You also can set a default behaviour with CMD instruction in your Dockerfile so you won't have to give this command to your container each time you want to run it.
EDIT - about container removing :
Containers and images are different.
A container is an instance of an image.
You can run several containers from the same image.
The container automatically stops when the process it runs terminates.
But the container isn't deleted (just stopped, so you can restart it).
But if you want to remove it (removing a container doesn't remove the image) you have two ways to do :
automatically removing it at the end of the process by adding --rm option to docker run.
Manually removing it by using the docker rm command and giving it the container ID or its name (a container has to be stopped before being removed, use docker stop for this).
A usefull command :
Use docker ps to list containers. -q to display only the container IDs, -a to display even stopped containers.
More here.
EDIT 2:
This could also help you to discover docker if you didn't try it.
How to test the container or image after docker build?
In order to test you can add write a bash script which will do the job https://blog.brazdeikis.io/posts/docker-image-tests
Btw, from the post, I see that it does not match the question from the title.
So, Added a link for the souls who arrived here based on the title...
Download the latest shaded dist from https://github.com/dgroup/docker-unittests/releases:
wget https://github.com/dgroup/docker-unittests/releases/download/s1.1.1/docker-unittests-app-1.1.1.jar
De fine an *.yml file with tests.
version: 1.1
setup:
- apt-get update
- apt-get install -y tree
tests:
- assume: java version is 1.9, Debian build
cmd: java -version
output:
contains:
- openjdk version "9.0.1"
- build 9.0.1+11-Debian
- assume: curl version is 7.xxx
cmd: curl --version
output:
startsWith: curl 7.
matches:
- "^curl\\s7.*\\n.*\\nProtocols.+ftps.+https.+telnet.*\\n.*\\n$"
contains:
- AsynchDNS IDN IPv6 Largefile GSS-API
- assume: Setup section installed `tree`
cmd: tree --version
output:
contains: ["Steve Baker", "Florian Sesser"]
Run tests for image
java -jar docker-unittests.jar -f image-tests.yml -i openjdk:9.0.1-11
https://i.stack.imgur.com/DSv72.png

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