I am running into an issue trying to open the Dagster UI from inside a docker container. Furthermore, this is a step towards my larger of goal, of opening the dagster UI from a docker container, thats running on a Google Compute Engine. I am able to open and view the dagster UI locally when it is not inside the container. Here are some diagrams to explain my issue and goals. My issue: I am unable to open the Dagster UI on my local machine, when the dagster script is running from inside the docker container. What I have tried:

# My docker image:

FROM python:3.8-slim-buster

# This is to deal with an issue with the psutil package.
RUN apt-get update -y && apt-get install -y gcc
RUN apt-get -y install xauth

COPY requirements.txt requirements.txt
RUN pip3 install -r requirements.txt

COPY . .

EXPOSE 3000

CMD dagster dev -f run_dagster_pipeline.py

# Building the container. 

docker build -t py-gce .

# Output:

=> [internal] load build definition from Dockerfile                                            0.0s
 => => transferring dockerfile: 553B                                                            0.0s
 => [internal] load .dockerignore                                                               0.0s
 => => transferring context: 2B                                                                 0.0s
 => resolve image config for <http://docker.io/docker/dockerfile:1|docker.io/docker/dockerfile:1>                                      1.2s
 => CACHED <docker-image://docker.io/docker/dockerfile:1@sha256:39b85bbfa7536a5feceb7372a081764>  0.0s
 => [internal] load build definition from Dockerfile                                            0.0s
 => [internal] load .dockerignore                                                               0.0s
 => [internal] load metadata for <http://docker.io/library/python:3.8-slim-buster|docker.io/library/python:3.8-slim-buster>                       0.8s
 => [internal] load build context                                                               0.2s
 => => transferring context: 375.92kB                                                           0.2s
 => [1/6] FROM <http://docker.io/library/python:3.8-slim-buster@sha256:eb48d017c5e117d9fbcbe991b4dbc61|docker.io/library/python:3.8-slim-buster@sha256:eb48d017c5e117d9fbcbe991b4dbc61>  0.0s
 => CACHED [2/6] RUN apt-get update -y && apt-get install -y gcc                                0.0s
 => [3/6] RUN apt-get -y install xauth                                                          1.5s
 => [4/6] COPY requirements.txt requirements.txt                                                0.0s 
 => [5/6] RUN pip3 install -r requirements.txt                                                 68.0s 
 => [6/6] COPY . .                                                                              0.3s 
 => exporting to image                                                                          2.2s 
 => => exporting layers                                                                         2.2s 
 => => writing image sha256:34ffd1197f7235be0493d3be985d70a053c2a48b9c421ee328e0f324b041dd13    0.0s 
 => => naming to <http://docker.io/library/py-gce|docker.io/library/py-gce>                                                       0.0s

# Running the container and porting to different port. 

docker run -p 8080:3000 py-gce

# Output:

2023-06-03 17:37:12 +0000 - dagster - INFO - Using temporary directory /tmpkcsq9so9 for storage. This will be removed when dagster dev exits.
2023-06-03 17:37:12 +0000 - dagster - INFO - To persist information across sessions, set the environment variable DAGSTER_HOME to a directory to use.
2023-06-03 17:37:12 +0000 - dagster - INFO - Launching Dagster services...

  Telemetry:

  As an open source project, we collect usage statistics to inform development priorities. For more
  information, read <https://docs.dagster.io/getting-started/telemetry>.

  We will not see or store solid definitions, pipeline definitions, modes, resources, context, or
  any data that is processed within solids and pipelines.

  To opt-out, add the following to $DAGSTER_HOME/dagster.yaml, creating that file if necessary:

    telemetry:
      enabled: false

  Welcome to Dagster!

  If you have any questions or would like to engage with the Dagster team, please join us on Slack
  (<<https://bit.ly/39dvSsF>>).

2023-06-03 17:37:14 +0000 - dagster.daemon - INFO - Instance is configured with the following daemons: ['AssetDaemon', 'BackfillDaemon', 'SchedulerDaemon', 'SensorDaemon']
2023-06-03 17:37:14 +0000 - dagster.daemon.SensorDaemon - INFO - Not checking for any runs since no sensors have been started.
2023-06-03 17:37:14 +0000 - dagit - INFO - Serving dagit on <<http://127.0.0.1:3000>> in process 9
2023-06-03 17:38:14 +0000 - dagster.daemon.SensorDaemon - INFO - Not checking for any runs since no sensors have been started.

# Go to open the web UI trying these URLs:

<<http://localhost:8080/>>
<<http://localhost:3000/>>
<http://localhost:127>.0.0.1:3000
<http://localhost:127>.0.0.1:8080
<http://localhost:0>.0.0.0:8080
<http://localhost:0>.0.0.0:3000

<<http://127.0.0.1:3000>>
<http://127.0.0.1:0>.0.0.0:3000
<<http://0.0.0.0:3000>>

<<http://127.0.0.1:8080>>
<http://127.0.0.1:0>.0.0.0:8080
<<http://0.0.0.0:8080>>

But all I get is: "This sight cant be reached"

# The next thing I try is to search the IP address for my docker container 
# using the following commands:

docker ps

# To get my docker image ID

docker inspect "my address"

# I search for my DOCKER IP address and get:
"IPAddress": "172.17.0.2",

# Then I try these URL's

<http://localhost:172>.17.0.2:8080
<http://localhost:172>.17.0.2
<http://localhost:172>.17.0.2:3000
<<http://172.17.0.2:8080>>

None of those work; however, this time it fails because it got stuck, and not because it was immediately denied. I found this post where they state that: “The

172.17.0.2

IP address is internal to the virtual machine that is running the Docker engine. You won’t be able to access it from your Windows host. The actual IP address of that virtual machine should be

192.168.99.100

which is the IP that ports would be mapped to if, in fact, you mapped any ports.” https://forums.docker.com/t/unable-to-access-my-first-container-on-172-17-0-2/54106 It appears they are obtain the

192.168.99.100

IP from running docker-machine IP; however, I do not have docker machine on my machine. I downloaded it, but still failed, then went onto read that

192.168.99.100

is the default value so should not be unique for my machine anyways. "This sight cant be reached: 192.168.99.100 took too long to respond" I am pretty lost at this point, have been trying for hours to resolve this seemingly simple task! Also, like shown in my first diagram, this is just a step towards my final goal of opening the Dagster UI from inside a docker container inside a GCE. So if you have any tips for that endevor, feel free to make suggestions for that as well. I have been all up down stack overflow and found similar issues, but the solutions are not working for me. I am not sure if this is a Dagster issue or Docker issue.