[CORD-3069] Update imagebuilder location, add docs
Change-Id: I02a14712205d1a4b90c2c976a193a550bad4d89c
diff --git a/SUMMARY.md b/SUMMARY.md
index 2fe6543..b5adf9c 100644
--- a/SUMMARY.md
+++ b/SUMMARY.md
@@ -33,6 +33,7 @@
* [Development Guide](developer/developer.md)
* [Getting the Source Code](developer/getting_the_code.md)
* [Developer Workflows](developer/workflows.md)
+ * [Building Docker Images](developer/imagebuilder.md)
* [VTN and Service Composition](xos/xos_vtn.md)
* [GUI Development](xos-gui/developer/README.md)
* [Quickstart](xos-gui/developer/quickstart.md)
diff --git a/developer/imagebuilder.md b/developer/imagebuilder.md
new file mode 100644
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--- /dev/null
+++ b/developer/imagebuilder.md
@@ -0,0 +1,218 @@
+# Building Docker Images with imagebuilder
+
+The current CORD implementation consists of many interrelated Docker images.
+Making sure that the images used in a deployment are consistent with the source
+tree on disk is a challenge and required a tool, `imagebuilder`, to be
+developed to perform image rebuilds in a consistent and efficient manner.
+
+Imagebuilder is currently used to build the XOS, ONOS, and the `mavenrepo`
+(source of ONOS Apps used in CORD) images, and pull down other required images.
+
+While imagebuilder will pull down required images from DockerHub and build/tag
+images, it does not push those images or delete obsolete ones. These tasks are
+left to other software (Ansible, Jenkins) which should take in imagebuilder's
+YAML output and take the appropriate actions.
+
+## Obtaining and rebuilding images
+
+For the normal build process, you won't need to manually download images as the
+`docker-images` make target that runs imagebuilder will automatically be run as
+a part of the build process.
+
+If you do need to rebuild images, there is a `make clean-images` target that
+will force imagebuilder to be run again and images to be moved into place.
+
+## Adding a new Docker image to CORD
+
+There are several cases where an Image would need to be added to CORD.
+
+### Adding an image developed outside of CORD
+
+There are cases where a 3rd party image developed outside of CORD may be
+needed. This is the case with ONOS, Redis, and a few other pieces of software
+that are already containerized, and we deploy as-is (or with minor
+modifications).
+
+To do this, add the full name of the image, including a version tag, to the
+`pull_only_images` list in the `docker_images.yml` file. As frequently only a
+subset of this list is needed for a specific helm chart, you can create a YAML
+file with a `docker_image_whitelist` list - see
+`cord/helm-charts/examples/*-images.yaml` for examples.
+
+These images will be retagged with a `candidate` tag after being pulled.
+
+### Adding a synchronizer image
+
+Adding a synchronizer image is usually as simple as adding it to the
+`buildable_images` list in the `automation-tools/developer/docker_images.yml`
+file.
+
+If you are adding a new service that is not in the repo manifest yet, you may
+have to add your service's directory to the `.repo/manifest.xml` file and then
+list it in `build/docker_images.yml`, so it can build the synchronizer image
+locally.
+
+### Adding other CORD images
+
+If you want imagebuilder to build an image from a Dockerfile somewhere in the
+CORD source tree, you need to add it to the `buildable_images` list in the
+`docker_images.yml` file (see that file for the specific format), then making
+sure the image name is listed in the `docker_image_whitelist` list.
+
+Note that you don't need to add external parent images to the
+`pull_only_images` in this manner - those are determined by the `FROM` line in
+`Dockerfile`
+
+## Debugging imagebuilder
+
+If you get a different error or think that imagebuilder isn't working
+correctly, please rerun it with the `-vv` ("very verbose") option, read through
+the output carefully, and then post about the issue on the mailing list or
+Slack.
+
+If an image is not found on Dockerhub (for example, if you have local
+modifications to the `Dockerfile` or context, or are have a patchset checked
+out), you may see a 404 error like the following in the logs. If this happens,
+imagebuilder will attempt to build the image from scratch rather than pulling
+it:
+
+```python
+NotFound: 404 Client Error: Not Found ("{"message":"manifest for xosproject/xos-gui-extension-builder:<hash> not found"}")
+```
+
+Run `imagebuilder.py -h` for a list of other supported arguments.
+
+## How Imagebuilder works
+
+The imagebuilder program performs the following steps when run:
+
+1. Reads the [repo manifest file](https://github.com/opencord/manifest/blob/master/default.xml)
+ (checked out as `.repo/manifest`) to get a list of the CORD git repositories.
+
+2. Reads the `automation-tools/developer/docker_images.yml` file and optionally
+ a filter file with a `docker_image_whitelist` list.
+
+3. For every container that is needed, reads the Dockerfile and determines if
+ any parent images are needed, and creates a tree to order image building.
+
+4. Determines which images need to be rebuilt based on:
+
+ * Whether the image exists and has current tags on it. If an image is
+ tagged with the `candidate` tag, but shouldn't be this tag is removed.
+ * If the Docker build context is *dirty* or differs (is on a different
+ branch) from the git tag specified in the repo manifest
+ * If the image's parent (or grandparent, etc.) needs to be rebuilt
+
+5. Using this information downloads (pulls) or builds images as needed in a
+ way that is consistent with the CORD source that is on disk. If an image
+ build is needed, the Docker output of that build is saved to
+ `build/image_logs` on the system where Imagebuilder executes (the
+ `buildhost` in inventory).
+
+6. Tags the image with the `candidate` and (if clean) git hash tags.
+
+7. Creates a YAML output file that describes the work it performed, for later
+ use (pushing images, retagging, etc.), and optional a graphviz `.dot` graph
+ file showing the relationships between images.
+
+## Image Tagging
+
+CORD container images frequently have multiple tags. The two most common ones
+are:
+
+* The string `candidate`, which says that the container is ready to be deployed
+ on a CORD POD
+* The git commit hash, which is either pulled from DockerHub, or applied when a
+ container is built from an untouched (according to git) source tree. Images
+ built from a modified source tree will not be tagged in this way.
+
+Imagebuilder use this git hash tag as well as labels on the image of the git
+repos of parent images to determine whether an image is correctly built from
+the checked out source tree.
+
+## Image labels
+
+Imagebuilder uses a Docker label scheme to determine whether an image needs to
+be rebuilt, which is added to the image when it is built. Docker images used
+in CORD must apply labels in their Dockerfiles which are specified by
+[label-schema.org](http://label-schema.org) - see there for examples, and below
+for a few notes that clear up the ambiguity within that spec.
+
+Required labels for every CORD image:
+
+* `org.label-schema.version`
+* `org.label-schema.name`
+* `org.label-schema.vcs-url`
+* `org.label-schema.build-date`
+
+Required for clean builds:
+
+* `org.label-schema.version` : *git branch name, ex: `opencord/master`,
+ `opencord/cord-4.0`, , etc.*
+* `org.label-schema.vcs-ref` : *the full 40 character SHA-1 git commit hash,
+ not shortened*
+
+Required for dirty builds:
+
+* `org.label-schema.version` : *set to the string `dirty` if there is any
+ differences from the master commit to the build context (either on a
+ different branch, or untracked/changed files in context)*
+* `org.label-schema.vcs-ref` - *set to a commit hash if build context is clean
+ (ie, on another unnamed branch/patchset), or the empty string if the build
+ context contains untracked/changed files.*
+
+For images that use components from another repo (like chameleon being
+integrated with the XOS containers, or maven repo which contains artifacts from
+multiple onos-apps repos), the following labels should be set for every
+sub-component, with the repo name (same as org.label-schema.name) replacing
+`<reponame>`, and the value being the same value as the label-schema
+one would be:
+
+* `org.opencord.component.<reponame>.version`
+* `org.opencord.component.<reponame>.vcs-ref`
+* `org.opencord.component.<reponame>.vcs-url`
+
+These labels are applied by using the `ARG` and `LABEL` option in the
+Dockerfile. The following is an example set of labels for an image that uses
+files from the chameleon and XOS repositories as components:
+
+```dockerfile
+# Label image
+ARG org_label_schema_schema_version=1.0
+ARG org_label_schema_name=openstack-synchronizer
+ARG org_label_schema_version=unknown
+ARG org_label_schema_vcs_url=unknown
+ARG org_label_schema_vcs_ref=unknown
+ARG org_label_schema_build_date=unknown
+ARG org_opencord_vcs_commit_date=unknown
+ARG org_opencord_component_chameleon_version=unknown
+ARG org_opencord_component_chameleon_vcs_url=unknown
+ARG org_opencord_component_chameleon_vcs_ref=unknown
+ARG org_opencord_component_xos_version=unknown
+ARG org_opencord_component_xos_vcs_url=unknown
+ARG org_opencord_component_xos_vcs_ref=unknown
+
+LABEL org.label-schema.schema-version=$org_label_schema_schema_version \
+ org.label-schema.name=$org_label_schema_name \
+ org.label-schema.version=$org_label_schema_version \
+ org.label-schema.vcs-url=$org_label_schema_vcs_url \
+ org.label-schema.vcs-ref=$org_label_schema_vcs_ref \
+ org.label-schema.build-date=$org_label_schema_build_date \
+ org.opencord.vcs-commit-date=$org_opencord_vcs_commit_date \
+ org.opencord.component.chameleon.version=$org_opencord_component_chameleon_version \
+ org.opencord.component.chameleon.vcs-url=$org_opencord_component_chameleon_vcs_url \
+ org.opencord.component.chameleon.vcs-ref=$org_opencord_component_chameleon_vcs_ref \
+ org.opencord.component.xos.version=$org_opencord_component_xos_version \
+ org.opencord.component.xos.vcs-url=$org_opencord_component_xos_vcs_url \
+ org.opencord.component.xos.vcs-ref=$org_opencord_component_xos_vcs_ref
+```
+
+Labels on a built image can be seen by running `docker inspect <image name or id>`
+
+## Automating image builds
+
+There is a [Jenkinsfile.imagebuilder](https://github.com/opencord/cord/blob/{{
+book.branch }}/Jenkinsfile.imagebuilder) that can be run in a Jenkins
+instance and will build and push images to DockerHub. This is how the CORD
+team pre-builds and publishes images for public use.
+
diff --git a/developer/workflows.md b/developer/workflows.md
index 4fd8f8e..0c071bf 100644
--- a/developer/workflows.md
+++ b/developer/workflows.md
@@ -69,8 +69,8 @@
Then you’ll need to build the XOS containers from source:
```shell
-cd ~/cord/build
-python scripts/imagebuilder.py -f ../helm-charts/examples/filter-images.yaml
+cd ~/cord/automation-tools
+./developer/imagebuilder.py -f ../helm-charts/examples/filter-images.yaml
```
At this point the images containing your changes will be available