kafka-connect losing plugin configuration sometimes on abrupt restart of the node - docker

This is the docker image we use to host docker-connect with the plugins
FROM confluentinc/cp-kafka-connect:5.3.1
ENV CONNECT_PLUGIN_PATH=/usr/share/java
# JDBC-MariaDB
RUN wget -nv -P /usr/share/java/kafka-connect-jdbc/ https://downloads.mariadb.com/Connectors/java/connector-java-2.4.4/mariadb-java-client-2.4.4.jar
# SNMP Source
RUN wget -nv -P /tmp/ https://github.com/name/kafka-connect-snmp/releases/download/0.0.1.11/kafka-connect-snmp-0.0.1.11.tar.gz
RUN mkdir /tmp/kafka-connect-snmp && tar -xf /tmp/kafka-connect-snmp-0.0.1.11.tar.gz -C /tmp/kafka-connect-snmp/
RUN mv /tmp/kafka-connect-snmp/usr/share/kafka-connect/kafka-connect-snmp /usr/share/java/
Now for some reason, when the node is restarted or shutdown abruptly, the plugin configurations are lost and unable to find any plugins.
Could someone please point out where might be the problem or steps to verify what is going wrong?
PS: I am unable to get the logs of any kind, due to some strict policies

Related

Self hosted GitHub Action Runner jobs failing

We make use of Github Self-Hosted action runners running on EC2 machines (m5.xlarge). We use these as part of our CI/CD pipeline to support docker image builds and automated testing. This solution has worked fine for the last year or so, but all of a sudden yesterday, the builds started to fail with the following error message :
time="2023-02-03T12:00:13Z" level=error msg="error waiting for container: unexpected EOF"
My understanding of this is that it is typically due to docker containers running out of resources (CPU / Memory Limit) being hit but given that these are m5.xlarges (4 vCPU and 16GB Memory) I'm a little surprised. Our builds make use of NPM which I understand can be quite resource hungry but monitoring a container during its execution showed that it was nowhere near the limits of the node:
I've tried to cycle the nodes but there is no difference in behaviour. The following user-data script is used with these nodes which connects it to our Github account and makes it available for jobs. I've also tried using the latest actions-runneer package, but again, no change in behaviour. What other reasons could this error be thrown for as i'm a bit stumped by this.
#!/bin/sh
set -e
curl https://get.docker.com | bash
apt install -y python3-pip jq
pip3 install awscli
mkdir actions-runner && cd actions-runner
curl -O -L https://github.com/actions/runner/releases/download/v2.286.0/actions-runner-linux-x64-2.286.0.tar.gz
tar xzf ./actions-runner-linux-x64-2.286.0.tar.gz
chown -R ubuntu:ubuntu .
instance_id="$(curl -s http://169.254.169.254/latest/meta-data/instance-id)"
url="https://api.github.com/orgs/<REMOVED>/actions/runners/registration-token"
token=$(curl -s -u "<REMOVED>:<REMOVED>" -X POST "$url" | jq -r .token)
sudo -u ubuntu ./config.sh \
--name "products-stage-ec2-runner-$instance_id" \
--token "$token" \
--url "https://github.com/<REMOVED>" \
--labels "<REMOVED>" \
--unattended
sudo ./svc.sh install
sudo ./svc.sh start
See details on my comment of how I resolved this.

How to access root folder inside a Docker container

I am new to docker, and am attempting to build an image that involves performing an npm install. Some of our the dependencies are coming from private repos we have, and I am hitting an SSH related issue:
I realised I was not supplying any form of SSH details to my file, and came across various posts online about how to do this using args into the docker build command.
So taken from here, I have added the following to my dockerfile before the npm install command gets run:
ARG ssh_prv_key
ARG ssh_pub_key
RUN apt-get update && \
apt-get install -y \
git \
openssh-server \
libmysqlclient-dev
# Authorize SSH Host
RUN mkdir -p /root/.ssh && \
chmod 0700 /root/.ssh && \
ssh-keyscan github.com > /root/.ssh/known_hosts
# Add the keys and set permissions
RUN echo "$ssh_prv_key" > /root/.ssh/id_rsa && \
echo "$ssh_pub_key" > /root/.ssh/id_rsa.pub && \
chmod 600 /root/.ssh/id_rsa && \
chmod 600 /root/.ssh/id_rsa.pub
So running the docker build command again with the correct args supplied, I do see further activity in the console that suggests my SSH key is being utilised:
But as you can see I am getting no hostkey alg messages and
I still getting the same 'Host key verification failed' error. I was wondering if I could view the log file it references in the error:
Do I need to get the image running in order to be able to connect to it and browse the 'root' folder?
I hope I have made sense, please be gentle I am a docker noob!
Thanks
The lines that start with —-> in the docker build output are valid Docker image IDs. You can pick any of these and docker run them:
docker run --rm -it 59c45dac474a sh
If a step is actually failing, one useful debugging trick is to launch the image built in the step before it and run the command by hand.
Remember that anyone who has your image can do this; the way you’ve built it, if you ever push your image to any repository, your ssh private key is there for the taking, and you should probably consider it compromised. That’s doubly true since it will also be there in plain text in docker history output.

Running sbt in docker as non-root user

Trying to create a docker image that has sbt installed and can build sbt projects but, when building, will not be running as the root user (this is all in the context of running Jenkins inside docker).
Dockerfile sets up sbt
ENV SBT_VERSION=1.1.6
RUN \
curl -L -o sbt-$SBT_VERSION.deb http://dl.bintray.com/sbt/debian/sbt-$SBT_VERSION.deb && \
dpkg -i sbt-$SBT_VERSION.deb && \
rm sbt-$SBT_VERSION.deb && \
apt-get update && \
apt-get install sbt && \
sbt sbtVersion
And if I then run sbt as the root user, all works ok
docker exec -u root myjenkins sbt sbtVersion
produces
[warn] No sbt.version set in project/build.properties, base directory: /
[info] Set current project to root (in build file:/)
[info] 1.1.6
But when I run sbt as the jenkins user, it tries to download sbt 1.1.6 again and eventually fails when it tries to modify an apt system file.
docker exec -u jenkins myjenkins sbt sbtVersion
produces:
Getting org.scala-sbt sbt 1.1.6 (this may take some time)...
downloading https://repo1.maven.org/maven2/org/scala-sbt/sbt/1.1.6/sbt-1.1.6.jar ...
[SUCCESSFUL ] org.scala-sbt#sbt;1.1.6!sbt.jar (68ms)
.
.
.
[warn] No sbt.version set in project/build.properties, base directory: /
[error] java.io.FileNotFoundException: /var/cache/apt/archives/lock (Permission denied)
I understand that all of the "RUN" commands in your Dockerfile are as a root user.
SBT downloading Scala: Check where it is downloading. SBT by default downloads dependencies on ~/.ivy2 (and/or ~/.m2). If you change user, your home also changes, so it will look for dependencies in /home/jenkins/.ivy2, then on .ivy2 (double-check on this), which do not have those dependencies downloaded already, so it tries to download them.
About the var/cache/apt/archives/lock, it is trying to install via SBT via apt with your jenkins user, when you need to be privileged user to use apt. Your app-user should not need to install anything (or anything that requires root access), but rather build an image with all required installs and then use it as a separate user. Also, if apt gives you headaches, you can just install via download into folder, something like:
RUN \
curl -fsL http://downloads.typesafe.com/scala/$SCALA_VERSION/scala-$SCALA_VERSION.tgz | tar xfz - -C /usr/local && \
ln -s /usr/local/scala-$SCALA_VERSION/bin/* /usr/local/bin/
PS: You may want to run your container always as jenkins user, in that case you can use USER jenkins after you finished installations and do any additional unprivileged operations there.

Docker run desktop environment

The question is most clear,
How to start complete desktop environment (KDE, XFCE, Gnome doesn't matter) in the Docker remote container.
I were digging over the internet and there are lots of questions about the related topic, but not the same, they all about how to run GUI application not the full desktop.
What I found out:
Necessary run Xvfb
Somehow run e.g. Xfce in that FrameBuffer
Allow x11vnc to share that running X environment
But I'm stuck here actually, always getting whatever errors:
... (EE) Invalid screen configuration 1024x768 for -screen 0
... Cannot open /dev/tty0 (No such file or directory)
Could you give some Dockerfile lines in order reach the goal?
That is I was looking for, the simplest form of the desktop in Docker:
FROM ubuntu
RUN apt-get update
RUN apt-get install xfce4 -y
RUN apt-get install xfce4-goodies -y
RUN apt-get purge -y pm-utils xscreensaver*
RUN apt-get install wget -y
EXPOSE 5901
RUN wget -qO- https://dl.bintray.com/tigervnc/stable/tigervnc-1.8.0.x86_64.tar.gz | tar xz --strip 1 -C /
RUN mkdir ~/.vnc
RUN echo "123456" | vncpasswd -f >> ~/.vnc/passwd
RUN chmod 600 ~/.vnc/passwd
CMD ["/usr/bin/vncserver", "-fg"]
Unfortunately I could not sort out with x11vnc and xvfb. But TigerVNC turned out much better.
This sample generate container with xfce gui and run vncserver with 123456 password. There is no need to overwrite ~/.vnc/xstartup manually because TigerVNC starts up X server by default!
To run the server:
sudo docker run --rm -dti -p 5901:5901 3ab3e0e7cb
To connect there with vncviewer:
vncviewer -AutoSelect 0 -QualityLevel 9 -CompressLevel 0 192.168.1.100:5901
Also you could not care about screen resolution because by default it will resize to fit your screen:
You may also encounter the issue with ipc_channel_posix (chrome and other browsers will not work properly) to eliminate this run container with memory sharing:
docker run -d --shm-size=2g --privileged -p 5901:5901 image-name
x11docker allows to run desktop environments as well as single GUI applications in docker.
Could you give some Dockerfile lines in order reach the goal?
Example desktop images on docker hub.
x11docker does a lot of setup to keep container isolation and provides some additional options like hardware acceleration or pulseaudio sound. Example:
x11docker --desktop x11docker/lxde
x11docker also supports network setups with SSH, VNC and HTML5
Example for SSH setup with xpra:
read Xenv < <(x11docker --xdummy --display=30 x11docker/lxde pcmanfm)
echo $Xenv && export $Xenv
# replace "start" with "start-desktop" to forward a desktop environment
xpra start :30 --use-display --start-via-proxy=no
From client system, connect with
xpra attach ssh:HOSTNAME:30 # replace HOSTNAME with IP or host name of ssh server
Without x11docker:
A quite short setup using Xephyr as nested X server on host is:
Xephyr :1
docker run -v /tmp/.X11-unix/X1:/tmp/.X11-unix/X1:rw \
-e DISPLAY=:1 \
x11docker/xfce
A short Dockerfile with Xfce desktop:
FROM debian:stretch
ENV DEBIAN_FRONTEND noninteractive
RUN apt-get update && apt-get install -y --no-install-recommends xfce4 dbus-x11
CMD startxfce4

How to add a file to an image in Dockerfile without using the ADD or COPY directive

I need the contents of a large *.zip file (5 gb) in my Docker container in order to compile a program. The *.zip file resides on my local machine. The strategy for this would be:
COPY program.zip /tmp/
RUN cd /tmp \
&& unzip program.zip \
&& make
After having done this I would like to remove the unzipped directory and the original *.zip file because they are not needed any more. The problem is that the COPY (and also the ADD directive) will add a layer to the image that will contain the file program.zip which is problematic as may image will be at least 5gb big. Is there a way to add a file to a container without using COPY or ADD directive? wget will not work as the mentioned *.zip file is on my local machine and curl file://localhost/home/user/program.zip -o /tmp/program.zip will not work either.
It is not straightforward but it can be done via wget or curl with a little support from python. (All three tools should usually be available on a *nix system.)
wget will not work when no url is given and
curl file://localhost/home/user/program.zip -o /tmp/
will not work from within a Dockerfile's RUN instruction. Hence, we will need a server which wget and curl can access and download program.zip from.
To do this we set up a little python server which serves our http requests. We will be using the http.server module from python for this. (You can use python or python 3. It will work with both.).
python -m http.server --bind 192.168.178.20 8000
The python server will serve all files in the directory it is started in. So you should make sure that you start your server either in the directory the file you want to download during your image build resides in or create a temporary directory which contains your program. For illustration purposes let's create the file foo.txt which we will later download via wget in our Dockerfile:
echo "foo bar" > foo.txt
When starting the http server, it is important, that we specify the IP address of our local machine on the LAN. Furthermore, we will open Port 8000. Having done this we should see the following output:
python3 -m http.server --bind 192.168.178.20 8000
Serving HTTP on 192.168.178.20 port 8000 ...
Now we build a Dockerfile to illustrate how this works. (We will assume that the file foo.txt should be downloaded into /tmp):
FROM debian:latest
RUN apt-get update -qq \
&& apt-get install -y wget
RUN cd /tmp \
&& wget http://192.168.178.20:8000/foo.txt
Now we start the build with
docker build -t test .
During the build you will see the following output on our python server:
172.17.0.21 - - [01/Nov/2014 23:32:37] "GET /foo.txt HTTP/1.1" 200 -
and the build output of our image will be:
Step 2 : RUN cd /tmp && wget http://192.168.178.20:8000/foo.txt
---> Running in 49c10e0057d5
--2014-11-01 22:56:15-- http://192.168.178.20:8000/foo.txt
Connecting to 192.168.178.20:8000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25872 (25K) [text/plain]
Saving to: `foo.txt'
0K .......... .......... ..... 100% 129M=0s
2014-11-01 22:56:15 (129 MB/s) - `foo.txt' saved [25872/25872]
---> 5228517c8641
Removing intermediate container 49c10e0057d5
Successfully built 5228517c8641
You can then check if it really worked by starting and entering a container from the image you just build:
docker run -i -t --rm test bash
You can then look in /tmp for foo.txt.
We can now add any file to our image without creating an new layer. Assuming you want to add a program of about 5 gb as mentioned in the question we could do:
FROM debian:latest
RUN apt-get update -qq \
&& apt-get install -y wget
RUN cd /tmp \
&& wget http://conventiont:8000/program.zip \
&& unzip program.zip \
&& cd program \
&& make \
&& make install \
&& cd /tmp \
&& rm -f program.zip \
&& rm -rf program
In this way we will not be left with 10 gb of cruft.
There's no way to do this. A feature request is here https://github.com/docker/docker/issues/3156.
Can you not map a local folder to the container when launched and then copy the files you need.
sudo docker run -d -P --name myContainerName -v /localpath/zip_extract:/container/path/ yourContainerID
https://docs.docker.com/userguide/dockervolumes/
I have posted a similar answer here: https://stackoverflow.com/a/37542913/909579
You can use docker-squash to squash newly created layers. That will essentially remove the archive from final image if you remove it in subsequent RUN instruction.

Resources