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Posted to github@beam.apache.org by GitBox <gi...@apache.org> on 2020/12/04 21:59:01 UTC
[GitHub] [beam] emilymye commented on a change in pull request #13420: Rewrite container docs for custom containers
emilymye commented on a change in pull request #13420:
URL: https://github.com/apache/beam/pull/13420#discussion_r536408069
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File path: website/www/site/content/en/documentation/runtime/environments.md
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@@ -17,54 +17,175 @@ limitations under the License.
# Container environments
-The Beam SDK runtime environment is isolated from other runtime systems because the SDK runtime environment is [containerized](https://s.apache.org/beam-fn-api-container-contract) with [Docker](https://www.docker.com/). This means that any execution engine can run the Beam SDK.
+The Beam SDK runtime environment can be [containerized](https://www.docker.com/resources/what-container) with [Docker](https://www.docker.com/) to isolate it from other runtime systems. To learn more about the container environment, read the Beam [SDK Harness container contract](https://s.apache.org/beam-fn-api-container-contract).
-This page describes how to customize, build, and push Beam SDK container images.
+Prebuilt SDK container images are released per supported language during Beam releases and pushed to [Docker Hub](https://hub.docker.com/search?q=apache%2Fbeam&type=image).
-Before you begin, install [Docker](https://www.docker.com/) on your workstation.
+## Custom container images
-## Customizing container images
+You may want to customize container images for many reasons, including:
-You can add extra dependencies to container images so that you don't have to supply the dependencies to execution engines.
+* Pre-installing additional dependencies
+* Launching third-party software in the worker environment
+* Further customizing the execution environment
-To customize a container image, either:
-* [Write a new](#writing-new-dockerfiles) [Dockerfile](https://docs.docker.com/engine/reference/builder/) on top of the original.
-* [Modify](#modifying-dockerfiles) the [original Dockerfile](https://github.com/apache/beam/blob/master/sdks/python/container/Dockerfile) and reimage the container.
+ This guide describes how to create and use customized containers for the Beam SDK.
-It's often easier to write a new Dockerfile. However, by modifying the original Dockerfile, you can customize anything (including the base OS).
+### Prerequisites
+
+* You will need to use Docker, either by [installing Docker tools locally](https://docs.docker.com/get-docker/) or using build services that can run Docker, such as [Google Cloud Build](https://cloud.google.com/cloud-build/docs/building/build-containers).
+* You will need to have a container registry accessible by your execution engine or runner to host a custom container image. Options include [Docker Hub](https://hub.docker.com/) or a "self-hosted" repository, including cloud-specific container registries like [Google Container Registry](https://cloud.google.com/container-registry) (GCR) or [Amazon Elastic Container Registry](https://aws.amazon.com/ecr/) (ECR).
+
+> **NOTE**: On Nov 20, 2020, Docker Hub put [rate limits](https://www.docker.com/increase-rate-limits) into effect for anonymous and free authenticated use, which may impact larger pipelines that pull containers several times.
+
+For optimal user experience, we also recommend you use the latest released version of Beam.
+
+### Building and pushing custom container images
+
+Beam [SDK container images](https://hub.docker.com/search?q=apache%2Fbeam&type=image) are built from Dockerfiles checked into the [Github](https://github.com/apache/beam) repository and published to Docker Hub for every release. You can build customized containers in one of two ways:
+
+1. **[Writing a new](#writing-new-dockerfiles) Dockerfile based on a released container image**. This is sufficient for simple additions to the image, such as adding artifacts or environment variables.
+2. **[Modifying](#modifying-dockerfiles) a source Dockerfile in [Beam](https://github.com/apache/beam)**. This method requires building from Beam source but allows for greater customization of the container (including replacement of artifacts or base OS/language versions).
+
+#### Writing a new Dockerfile based on an existing published container image {#writing-new-dockerfiles}
+
+Steps:
+
+1. Create a new Dockerfile that designates a base image using the [FROM instruction](https://docs.docker.com/engine/reference/builder/#from). As an example, this `Dockerfile`:
+
+```
+FROM apache/beam_python3.7_sdk:2.25.0
+
+ENV FOO=bar
+COPY /src/path/to/file /dest/path/to/file/
+```
+
+uses the prebuilt Python 3.7 SDK container image [`beam_python3.7_sdk`](https://hub.docker.com/r/apache/beam_python3.7_sdk) tagged at (SDK version) `2.25.0`, and adds an additional environment variable and file to the image.
+
+
+2. [Build](https://docs.docker.com/engine/reference/commandline/build/) and [push](https://docs.docker.com/engine/reference/commandline/push/) the image using Docker.
-### Writing new Dockerfiles on top of the original {#writing-new-dockerfiles}
-1. Pull a [prebuilt SDK container image](https://hub.docker.com/search?q=apache%2Fbeam&type=image) for your [target](https://docs.docker.com/docker-hub/repos/#searching-for-repositories) language and version. The following example pulls the latest Python SDK:
```
-docker pull apache/beam_python3.7_sdk
+export BASE_IMAGE="apache/beam_python3.7_sdk:2.25.0"
+export IMAGE_NAME="myremoterepo/mybeamsdk"
+export TAG="latest"
+
+# Optional - pull the base image into your local Docker daemon to ensure
+# you have the most up-to-date version of the base image locally.
+docker pull "${BASE_IMAGE}"
+
+docker build -f Dockerfile -t "${IMAGE_NAME}:${TAG}" .
+docker push "${IMAGE_NAME}:${TAG}"
```
-2. [Write a new Dockerfile](https://docs.docker.com/develop/develop-images/dockerfile_best-practices/) that [designates](https://docs.docker.com/engine/reference/builder/#from) the original as its [parent](https://docs.docker.com/glossary/?term=parent%20image).
-3. [Build](#building-container-images) a child image.
-### Modifying the original Dockerfile {#modifying-dockerfiles}
+**NOTE**: After pushing a container image, you should verify the remote image ID and digest should match the local image ID and digest, output from `docker build` or `docker images`.
+
+#### Modifying a source Dockerfile in Beam {#modifying-dockerfiles}
+
+This method will require building image artifacts from Beam source. For additional instructions on setting up your development environment, see the [Contribution guide](contribute/#development-setup).
+
+1. Clone the `beam` repository. It is recommended that you start from a stable
+ release branch rather than from master for both customizing the Dockerfile
+ and building image artifacts, and that you use the same version of the SDK
+ to run your pipeline with a custom container image.
-1. Clone the `beam` repository:
```
+export BEAM_SDK_VERSION="2.26.0"
+
git clone https://github.com/apache/beam.git
+git checkout origin/release-$BEAM_SDK_VERSION
+```
+
+3. Customize the `Dockerfile` for a given language. This file is typically in the `sdks/<language>/container` directory (e.g. the [Dockerfile for Python](https://github.com/apache/beam/blob/master/sdks/python/container/Dockerfile). If you're adding dependencies from [PyPI](https://pypi.org/), use [`base_image_requirements.txt`](https://github.com/apache/beam/blob/master/sdks/python/container/base_image_requirements.txt) instead.
+
+3. Navigate to the root directory of the local copy of your Apache Beam.
+
+4. Run Gradle with the `docker` target.
+
+
+```
+# The default repository of each SDK
+./gradlew :sdks:java:container:java8:docker
+./gradlew :sdks:java:container:java11:docker
+./gradlew :sdks:go:container:docker
+./gradlew :sdks:python:container:py36:docker
+./gradlew :sdks:python:container:py37:docker
+./gradlew :sdks:python:container:py38:docker
+
+# Shortcut for building all Python SDKs
+./gradlew :sdks:python:container buildAll
+```
+
+To examine the containers that you built, run `docker images`:
+
+```
+$> docker images
+REPOSITORY TAG IMAGE ID CREATED SIZE
+apache/beam_java8_sdk latest ... 1 min ago ...
+apache/beam_java11_sdk latest ... 1 min ago ...
+apache/beam_python3.6_sdk latest ... 1 min ago ...
+apache/beam_python3.7_sdk latest ... 1 min ago ...
+apache/beam_python3.8_sdk latest ... 1 min ago ...
+apache/beam_go_sdk latest ... 1 min ago ...
+```
+
+If you did not provide a custom repo/tag as additional parameters (see below), you can retag the image and [push](https://docs.docker.com/engine/reference/commandline/push/) the image using Docker to a remote repository.
+
+```
+export BEAM_SDK_VERSION="2.26.0"
+export IMAGE_NAME="myrepo/mybeamsdk"
+export TAG="${BEAM_SDK_VERSION}-custom"
+
+docker tag apache/beam_python3.6_sdk "${IMAGE_NAME}:${TAG}"
+docker push "${IMAGE_NAME}:${TAG}"
+```
+
+**NOTE**: After pushing a container image, verify the remote image ID and digest matches the local image ID and digest output from `docker_images`
+
+##### Additional build parameters
+
+The docker Gradle task defines a default image repository and [tag](https://docs.docker.com/engine/reference/commandline/tag/) is the SDK version defined at [gradle.properties](https://github.com/apache/beam/blob/master/gradle.properties). The default repository is the Docker Hub `apache` namespace, and the default tag is the [SDK version](https://github.com/apache/beam/blob/master/gradle.properties) defined at gradle.properties.
+
+You can specify a different repository or tag for built images by providing parameters to the build task. For example:
+
```
-2. Customize the [Dockerfile](https://github.com/apache/beam/blob/master/sdks/python/container/Dockerfile). If you're adding dependencies from [PyPI](https://pypi.org/), use [`base_image_requirements.txt`](https://github.com/apache/beam/blob/master/sdks/python/container/base_image_requirements.txt) instead.
-3. [Reimage](#building-container-images) the container.
+./gradlew :sdks:python:container:py36:docker -Pdocker-repository-root="example-repo" -Pdocker-tag="2.26.0-custom"
+```
+
+builds the Python 3.6 container and tags it as `example-repo/beam_python3.6_sdk:2.26.0-custom`.
+
+From Beam 2.21.0 and later, a `docker-pull-licenses` flag was introduced to add licenses/notices for third party dependencies to the docker images. For example:
+
+```
+./gradlew :sdks:java:container:java8:docker -Pdocker-pull-licenses
+```
+creates a Java 8 SDK image with appropriate licenses in `/opt/apache/beam/third_party_licenses/`.
+
+By default, no licenses/notices are added to the docker images.
-### Testing customized images
-To test a customized image locally, run a pipeline with PortableRunner and set the `--environment_config` flag to the image path:
+## Using container images in pipelines
+
+The common method for providing a container image requires using the PortableRunner and setting the `--environment_config` flag to a given image path.
+Other runners, such as Dataflow, support specifying containers with different flags.
{{< highlight class="runner-direct" >}}
+export IMAGE="my-repo/beam_python_sdk_custom"
+export TAG="X.Y.Z"
+
python -m apache_beam.examples.wordcount \
--input=/path/to/inputfile \
--output /path/to/write/counts \
--runner=PortableRunner \
--job_endpoint=embed \
---environment_config=path/to/container/image
+--environment_config="${IMAGE}:${TAG}"
{{< /highlight >}}
{{< highlight class="runner-flink-local" >}}
+export IMAGE="my-repo/beam_python_sdk_custom"
+export TAG="X.Y.Z"
+
# Start a Flink job server on localhost:8099
Review comment:
We are probably waiting until early next week to merge in - probably better to use the more accurate version of commands. Do you have an example of recommended arguments with FlinkRunner for Python/is that supported? I couldn't find one in the docs.
Also, should we be doing the same things for spark? Based on a quick look it doesn't look like we have the same functionality for Spark, but I'm not very familiar with either Flink or Spark.
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