I'm working with the servercore Windows docker image for CI purposes (i.e. building).
I'm fine building it, running it mounting the repo as a volume, launching it and keeping it listening on a specific port and launching exec "mountedFolder/script.bat".
docker build . -t build_image
docker run -d -t -p 8585:9090 -v $PATH:c:/repo build_image > id.txt
set /p id=<id.txt
docker exec %id% "build.bat"
But is there any way to launch the script (and cd-ing to its folder before launching it), in the run command itself? Something like
docker run --rm -v $PATH:c:/repo build_image /PATH/to/BAT/build.bat
I have a dockerfile: (these are the relevent commands)
RUN apk app --update bash openssh sshpass
CMD ["bin/sh", "/home/build/build.sh"]
Which my dockerfile gets ran by this command
docker run --rm -it -v $(pwd):/home <image-name>
and all of the commands within my bash script, that are within the mounted volume execute. These commands range from npm installs to using tar to zip up a file and I want to SFTP that tar.gz file.
I am using sshpass to automate logging in which I know isn't secured, but I'm not worried about that with this application.
sshpass -p <password> sftp -P <port> username#host << EOF
<command>
<command>
EOF
But the sshpass command is never executed. I've tested my docker run command by appending /bin/sh to it and trying it and it also does not run. The SFTP command by itself does.
And when I say it's never executed, I don't receive an error or anything.
Two possible reason
You apk command is wrong, it should be RUN apk add --update bash openssh sshpass, but I assume it typo
Seems like the known host entry is missing, you should check logs `docker logs -f , Also need to add entry in for known-host, check the suggested build script below.
Here is a working example that you can try
Dockerfile
FROM alpine
RUN apk add --update bash openssh sshpass
COPY build.sh /home/build/build.sh
CMD ["bin/sh", "/home/build/build.sh"]
build script
#!/bin/bash
echo "adding host to known host"
mkdir -p ~/.ssh
touch ~/.ssh/known_hosts
ssh-keyscan sftp >> ~/.ssh/known_hosts
echo "run command on remote server"
sshpass -p pass sftp foo#sftp << EOF
ls
pwd
EO
Now build the image, docker build -t ssh-pass .
and finally, the docker-compose for testing the above
version: '3'
services:
sftp-client:
image: ssh-pass
depends_on:
- sftp
sftp:
image: atmoz/sftp
ports:
- "2222:22"
command: foo:pass:1001
so you will able to connect the sftp container using docker-compose up
I have a little problem, when i run my container this:
docker run -it emails_request cucumber -t #teste_inserindo_email
It's ok.
But, when i run this:
docker run it emails_request
Where my #teste_inserindo_emails, is on my dockerfile
WORKDIR /app
COPY Gemfile .
RUN bundle install && bundle clean
COPY . /app
EXPOSE 80
RUN cucumber -t #teste_inserindo_email
#CMD ["cucumber", "-t", " #teste_inserindo_email"]
Not found, return:
$ docker run -t emails_request
irb(main):001:0>
Or:
$ docker run emails_request
Switch to inspect mode.
what's your question exactly? you can just run it manually by firing up a container with an interactive terminal from your image, and then run the commands you want, or have a script in the image (or mounted as a volume) and then pass the script as the entry command instead.
docker run -it IMAGE_ID bash (for running manual commands)
if you want to use a script instead, put an ENTRYPOINT script in your Dockerfile instead
This is my Dockerfile
# This Dockerfile describes the standard way to build
FROM centos:latest
MAINTAINER praveen
# Run a root to allow "rpm"
USER root
WORKDIR /root/
# Get the ACE-TAO rpm from seachange repo
COPY TAO-1.7.7-0.x86_64.rpm /root/TAO-1.7.7-0.x86_64.rpm
# Insatall the rpm
RUN rpm -ivh /root/TAO-1.7.7-0.x86_64.rpm
#Start the TAO service
#CMD /etc/init.d/tao start
COPY namingServiceConfig.sh /
RUN /namingServiceConfig.sh
EXPOSE 13021
EXPOSE 13022
EXPOSE 13023
ENV NS_PORTS=13021,13022,13023
#ENTRYPOINT /etc/init.d/tao start && bash
While doing the docker build
Whether it'll execute the shell script and reflect the changes as part images or while running the images using docker run its will reflect the changes to container level
In my case ,I'm suspecting that, it is executing while docker build and docker run both time
I'm using below commands as part of building and running via vagrant file
d.build_image "/vagrant/tao", args: " -t tao/basic"
d.run "tao/basic:latest",
args: " -t -d"\
" --name tao-basic"\
" -p 13021:13021"\
" -e NS_PORT=13025,13026,13027"
let me know, need any more information
The Dockerfile instructions (such as RUN etc...) are actioned at build time (docker build -t something . etc...). Only the CMD and ENTRYPOINT instructions happen at run time (when the container is started).
In your example the shell script will get run as part of the build and whatever changes occur will be committed as a new layer in the image.
I'm trying to build a new Docker image for our development process, using cpanm to install a bunch of Perl modules as a base image for various projects.
While developing the Dockerfile, cpanm returns a failure code because some of the modules did not install cleanly.
I'm fairly sure I need to get apt to install some more things.
Where can I find the /.cpanm/work directory quoted in the output, in order to inspect the logs? In the general case, how can I inspect the file system of a failed docker build command?
After running a find I discovered
/var/lib/docker/aufs/diff/3afa404e[...]/.cpanm
Is this reliable, or am I better off building a "bare" container and running stuff manually until I have all the things I need?
Everytime docker successfully executes a RUN command from a Dockerfile, a new layer in the image filesystem is committed. Conveniently you can use those layers ids as images to start a new container.
Take the following Dockerfile:
FROM busybox
RUN echo 'foo' > /tmp/foo.txt
RUN echo 'bar' >> /tmp/foo.txt
and build it:
$ docker build -t so-26220957 .
Sending build context to Docker daemon 47.62 kB
Step 1/3 : FROM busybox
---> 00f017a8c2a6
Step 2/3 : RUN echo 'foo' > /tmp/foo.txt
---> Running in 4dbd01ebf27f
---> 044e1532c690
Removing intermediate container 4dbd01ebf27f
Step 3/3 : RUN echo 'bar' >> /tmp/foo.txt
---> Running in 74d81cb9d2b1
---> 5bd8172529c1
Removing intermediate container 74d81cb9d2b1
Successfully built 5bd8172529c1
You can now start a new container from 00f017a8c2a6, 044e1532c690 and 5bd8172529c1:
$ docker run --rm 00f017a8c2a6 cat /tmp/foo.txt
cat: /tmp/foo.txt: No such file or directory
$ docker run --rm 044e1532c690 cat /tmp/foo.txt
foo
$ docker run --rm 5bd8172529c1 cat /tmp/foo.txt
foo
bar
of course you might want to start a shell to explore the filesystem and try out commands:
$ docker run --rm -it 044e1532c690 sh
/ # ls -l /tmp
total 4
-rw-r--r-- 1 root root 4 Mar 9 19:09 foo.txt
/ # cat /tmp/foo.txt
foo
When one of the Dockerfile command fails, what you need to do is to look for the id of the preceding layer and run a shell in a container created from that id:
docker run --rm -it <id_last_working_layer> bash -il
Once in the container:
try the command that failed, and reproduce the issue
then fix the command and test it
finally update your Dockerfile with the fixed command
If you really need to experiment in the actual layer that failed instead of working from the last working layer, see Drew's answer.
The top answer works in the case that you want to examine the state immediately prior to the failed command.
However, the question asks how to examine the state of the failed container itself. In my situation, the failed command is a build that takes several hours, so rewinding prior to the failed command and running it again takes a long time and is not very helpful.
The solution here is to find the container that failed:
$ docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
6934ada98de6 42e0228751b3 "/bin/sh -c './utils/" 24 minutes ago Exited (1) About a minute ago sleepy_bell
Commit it to an image:
$ docker commit 6934ada98de6
sha256:7015687976a478e0e94b60fa496d319cdf4ec847bcd612aecf869a72336e6b83
And then run the image [if necessary, running bash]:
$ docker run -it 7015687976a4 [bash -il]
Now you are actually looking at the state of the build at the time that it failed, instead of at the time before running the command that caused the failure.
Update for newer docker versions 20.10 onwards
Linux or macOS
DOCKER_BUILDKIT=0 docker build ...
Windows
# Command line
set DOCKER_BUILDKIT=0 docker build ...
# PowerShell
$env:DOCKER_BUILDKIT=0
Use
DOCKER_BUILDKIT=0 docker build ...
to get the intermediate container hashes as known from older versions.
On newer versions, Buildkit is activated per default. It is recommended to only use it for debugging purposes. Build Kit can make your build faster.
For reference:
Buildkit doesn't support intermediate container hashes: https://github.com/moby/buildkit/issues/1053
Thanks to #David Callanan and #MegaCookie for their inputs.
Docker caches the entire filesystem state after each successful RUN line.
Knowing that:
to examine the latest state before your failing RUN command, comment it out in the Dockerfile (as well as any and all subsequent RUN commands), then run docker build and docker run again.
to examine the state after the failing RUN command, simply add || true to it to force it to succeed; then proceed like above (keep any and all subsequent RUN commands commented out, run docker build and docker run)
Tada, no need to mess with Docker internals or layer IDs, and as a bonus Docker automatically minimizes the amount of work that needs to be re-done.
Currently with the latest docker-desktop, there isn't a way to opt out
of the new Buildkit, which doesn't support debugging yet (follow the
latest updates on this on this GitHub Thread:
https://github.com/moby/buildkit/issues/1472).
Find out at which line in your Dockerfile it is failing.
Add to the top of your Dockerfile: FROM xxx as debug
Add an additional target: FROM xxx as next just one line before the failing command (as you don't want to build that part). Example:
FROM xxx as debug
RUN echo "working command"
FROM xxx as next
RUN echoo "failing command"
Run docker build -f Dockerfile --target debug --tag debug .
Then you can debug the container with: docker run -it debug /bin/sh
You can quit the shell by pressing CTRL P + CTRL Q
If you want to use docker compose build instead of docker build it's possible by adding target: debug in your docker-compose.yml under build.
Then start the container by docker compose run xxxYourServiceNamexxx and use either:
The second top answer to find out how to run a shell inside the container.
Or add ENTRYPOINT /bin/sh before the FROM xxx as next line in your Dockerfile.
Debugging build step failures is indeed very annoying.
The best solution I have found is to make sure that each step that does real work succeeds, and adding a check after those that fails. That way you get a committed layer that contains the outputs of the failed step that you can inspect.
A Dockerfile, with an example after the # Run DB2 silent installer line:
#
# DB2 10.5 Client Dockerfile (Part 1)
#
# Requires
# - DB2 10.5 Client for 64bit Linux ibm_data_server_runtime_client_linuxx64_v10.5.tar.gz
# - Response file for DB2 10.5 Client for 64bit Linux db2rtcl_nr.rsp
#
#
# Using Ubuntu 14.04 base image as the starting point.
FROM ubuntu:14.04
MAINTAINER David Carew <carew#us.ibm.com>
# DB2 prereqs (also installing sharutils package as we use the utility uuencode to generate password - all others are required for the DB2 Client)
RUN dpkg --add-architecture i386 && apt-get update && apt-get install -y sharutils binutils libstdc++6:i386 libpam0g:i386 && ln -s /lib/i386-linux-gnu/libpam.so.0 /lib/libpam.so.0
RUN apt-get install -y libxml2
# Create user db2clnt
# Generate strong random password and allow sudo to root w/o password
#
RUN \
adduser --quiet --disabled-password -shell /bin/bash -home /home/db2clnt --gecos "DB2 Client" db2clnt && \
echo db2clnt:`dd if=/dev/urandom bs=16 count=1 2>/dev/null | uuencode -| head -n 2 | grep -v begin | cut -b 2-10` | chgpasswd && \
adduser db2clnt sudo && \
echo '%sudo ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
# Install DB2
RUN mkdir /install
# Copy DB2 tarball - ADD command will expand it automatically
ADD v10.5fp9_linuxx64_rtcl.tar.gz /install/
# Copy response file
COPY db2rtcl_nr.rsp /install/
# Run DB2 silent installer
RUN mkdir /logs
RUN (/install/rtcl/db2setup -t /logs/trace -l /logs/log -u /install/db2rtcl_nr.rsp && touch /install/done) || /bin/true
RUN test -f /install/done || (echo ERROR-------; echo install failed, see files in container /logs directory of the last container layer; echo run docker run '<last image id>' /bin/cat /logs/trace; echo ----------)
RUN test -f /install/done
# Clean up unwanted files
RUN rm -fr /install/rtcl
# Login as db2clnt user
CMD su - db2clnt
In my case, I have to have:
DOCKER_BUILDKIT=1 docker build ...
and as mentioned by Jannis Schönleber in his answer, there is currently no debug available in this case (i.e. no intermediate images/containers get created).
What I've found I could do is use the following option:
... --progress=plain ...
and then add various RUN ... or additional lines on existing RUN ... to debug specific commands. This gives you what to me feels like full access (at least if your build is relatively fast).
For example, you could check a variable like so:
RUN echo "Variable NAME = [$NAME]"
If you're wondering whether a file is installed properly, you do:
RUN find /
etc.
In my situation, I had to debug a docker build of a Go application with a private repository and it was quite difficult to do that debugging. I've other details on that here.
If you are using docker-compose to build docker images try to add DOCKER_BUILDKIT=0 before the command to see the last successful layer id
DOCKER_BUILDKIT=0 docker-compose ...
This will temporarily disable DOCKER_BUILDKIT for the command only.
Having the last layer id you can connect to it using the command from the top answer
docker run --rm -it LAST_LAYER_ID sh
my solution would be to see what step failed in the docker file, RUN bundle install in my case,
and change it to
RUN bundle install || cat <path to the file containing the error>
This has the double effect of printing out the reason for the failure, AND this intermediate step is not figured as a failed one by docker build. so it's not deleted, and can be inspected via:
docker run --rm -it <id_last_working_layer> bash -il
in there you can even re run your failed command and test it live.
What I would do is comment out the Dockerfile below and including the offending line. Then you can run the container and run the docker commands by hand, and look at the logs in the usual way. E.g. if the Dockerfile is
RUN foo
RUN bar
RUN baz
and it's dying at bar I would do
RUN foo
# RUN bar
# RUN baz
Then
$ docker build -t foo .
$ docker run -it foo bash
container# bar
...grep logs...
Still using BuildKit, as in Alexis Wilke's answer, you can use ktock/buildg.
See "Interactive debugger for Dockerfile" from Kohei Tokunaga
buildg is a tool to interactively debug Dockerfile based on BuildKit.
Source-level inspection
Breakpoints and step execution
Interactive shell on a step with your own debugigng tools
Based on BuildKit (needs unmerged patches)
Supports rootless
Example:
$ buildg.sh debug --image=ubuntu:22.04 /tmp/ctx
WARN[2022-05-09T01:40:21Z] using host network as the default
#1 [internal] load .dockerignore
#1 transferring context: 2B done
#1 DONE 0.1s
#2 [internal] load build definition from Dockerfile
#2 transferring dockerfile: 195B done
#2 DONE 0.1s
#3 [internal] load metadata for docker.io/library/busybox:latest
#3 DONE 3.0s
#4 [build1 1/2] FROM docker.io/library/busybox#sha256:d2b53584f580310186df7a2055ce3ff83cc0df6caacf1e3489bff8cf5d0af5d8
#4 resolve docker.io/library/busybox#sha256:d2b53584f580310186df7a2055ce3ff83cc0df6caacf1e3489bff8cf5d0af5d8 0.0s done
#4 sha256:50e8d59317eb665383b2ef4d9434aeaa394dcd6f54b96bb7810fdde583e9c2d1 772.81kB / 772.81kB 0.2s done
Filename: "Dockerfile"
2| RUN echo hello > /hello
3|
4| FROM busybox AS build2
=> 5| RUN echo hi > /hi
6|
7| FROM scratch
8| COPY --from=build1 /hello /
>>> break 2
>>> breakpoints
[0]: line 2
>>> continue
#4 extracting sha256:50e8d59317eb665383b2ef4d9434aeaa394dcd6f54b96bb7810fdde583e9c2d1 0.0s done
#4 DONE 0.3s
...