I am trying to replicate running this flow on my own laptop

Question

I am trying to replicate running this flow on my own laptop with Docker Desktop I have created a docker image but did not push it to e g DockerHub and registered the flow just like in the script to Prefect Cloud Started a docker agent and did a quick run from the UI So far so good everything works But when I modify the Dockerfile so that it can run as non root I can no longer do a successful run I get the following error from the agent ``` docker errors NotFound 404 Client Error for Not Found No such container f30a3e9241fab0d272c3f36eae16867487fb187b964c8b3f22bc8fd05d2aa4d0 ``` and the flow is stuck in submitted state Does anyone knows how to fix it Just to make sure the only difference between the successful run and the run stuck in submitted state is the fact that I added a non root user to the image

Matthias · Answer

FYI this is the Dockerfile ```FROM prefecthq prefect 0 15 6 python3 8 ENV PREFECT HOME= opt prefect WORKDIR $PREFECT HOME COPY flow py $PREFECT HOME flows flow py RUN useradd m prefect user amp amp make it so that the directories in $PREFECT HOME including $PREFECT HOME are world readable and executable chown R prefect user root $PREFECT HOME USER prefect user ENTRYPOINT bin sh c bash``` Note that it looks different from the one in the tutorial from Anna Geller but it works if I remove everything starting from the `RUN` statement

Matthias · Answer

Nevermind I solved the issue When I remove the ENTRYPOINT it works just fine for some reason

Anna Geller · Answer

Nice work It makes sense because Prefect sets the ENTRYPOINT itself to trigger the flow run I never set any <https github com anna geller packaging prefect flows blob master Dockerfile|entrypoints> when building images for Prefect flows

Matthias · Answer

That s very strange that Prefect does not overwrite the image s default entrypoint then no

Anna Geller · Answer

I think it s the other way around slightly smiling face you use Prefect s base image and you actually have overwritten the entrypoint set by Prefect that s why it didn t work for you If you don t set it you keep the entrypoint set in the Prefect s base image

Matthias · Answer

That s true in this example but the use case I have in mind is that I want to start from a regular Python base image The reason for this is that some companies only offer a curated list of base images that you are allowed to use Hence you cannot use Prefect s base image and have to start from scratch In that case you want to make sure the entrypoint is properly set In the job spec of the k8s runconfig this is indeed the case <https github com PrefectHQ prefect blob master src prefect agent kubernetes job spec yaml L15|https github com PrefectHQ prefect blob master src prefect agent kubernetes job spec yaml L15>

Matthias · Answer

So an easy solution would be to add the same to the docker agent here <https github com PrefectHQ prefect blob master src prefect agent docker agent py L473|https github com PrefectHQ prefect blob master src prefect agent docker agent py L473>

Anna Geller · Answer

I think to use your own custom base image it would be easier to replicate Prefect s <https github com PrefectHQ prefect blob master Dockerfile|Dockerfile> using your custom base image instead of changing commands used by Docker Kubernetes agent right Also the entrypoint is doing a bit more e g allows to install packages set on env variable ```pip install $EXTRA PIP PACKAGES``` Lastly Prefect is using the base Python image in the slim version which is pretty standard and commonly accepted for Python applications what else would you want to use instead e g Ubuntu base image and install Python yourself Having said that feel free to submit a PR or GitHub issue and we can discuss it further with other engineers if you feel like this is a problem we should address

Matthias · Answer

I m guessing that indeed replicating Prefect s Dockerfile solves the issue Thanks for the advice