ci: Remove drone(gen) from repo (#38739)

Remove `.drone.yml` and `dronegen` which generates it from the repo,
disabling drone on master. Remove references to drone in docs.

The remaining piplines in `.drone.yml` were the tag build and promote
pipelines which now run on GitHub Actions, the push build pipelines that
are currently of limited value and will be re-done differently with a
little thought, and the `teleport-docker-cron-ecr` pipeline which no
longer works as of v15 due to the removal of the legacy OCI images (the
teleport-labs stuff that the pipeline builds is to be removed shortly
too).

Makefile

@@ -896,7 +896,7 @@ endif
 test-sh:
 	@if ! type bats 2>&1 >/dev/null; then \
 		echo "Not running 'test-sh' target as 'bats' is not installed."; \
-		if [ "$${DRONE}" = "true" ]; then echo "This is a failure when running in CI." && exit 1; fi; \
+		if [ "$${CI}" = "true" ]; then echo "This is a failure when running in CI." && exit 1; fi; \
 		exit 0; \
 	fi; \
 	bats $(BATSFLAGS) ./assets/aws/files/tests
@@ -1065,7 +1065,7 @@ lint-sh:
 lint-helm:
 	@if ! type yamllint 2>&1 >/dev/null; then \
 		echo "Not running 'lint-helm' target as 'yamllint' is not installed."; \
-		if [ "$${DRONE}" = "true" ]; then echo "This is a failure when running in CI." && exit 1; fi; \
+		if [ "$${CI}" = "true" ]; then echo "This is a failure when running in CI." && exit 1; fi; \
 		exit 0; \
 	fi; \
 	for CHART in ./examples/chart/teleport-cluster ./examples/chart/teleport-kube-agent ./examples/chart/teleport-cluster/charts/teleport-operator; do \
@@ -1485,18 +1485,6 @@ init-submodules-e:
 	git submodule init e
 	git submodule update
 
-# dronegen generates .drone.yml config
-#
-#    Usage:
-#    - tsh login --proxy=platform.teleport.sh
-#    - tsh apps login drone
-#    - set $DRONE_TOKEN and $DRONE_SERVER (http://localhost:8080)
-#    - tsh proxy app --port=8080 drone
-#    - make dronegen
-.PHONY: dronegen
-dronegen:
-	go run ./dronegen
-
 # backport will automatically create backports for a given PR as long as you have the "gh" tool
 # installed locally. To backport, type "make backport PR=1234 TO=branch/1,branch/2".
 .PHONY: backport

build.assets/README.md

@@ -11,13 +11,13 @@ make
 
 # Safely updating build box Dockerfiles
 
-The build box images are used in Drone pipelines and GitHub Actions. The resulting image is pushed
-to Amazon ECR and ghcr.io. This means that to safely introduce changes to Dockerfiles, those changes
+The build box images are used in GitHub Actions. The resulting image is pushed
+to ghcr.io. This means that to safely introduce changes to Dockerfiles, those changes
 should be split into two stages:
 
 1. First you open a PR which updates a Dockerfile and get the PR merged.
-2. Once it's merged, Drone is going to pick it up, build a new build box image and push it to Amazon
-   ECR.
+2. Once it's merged, GitHub Actions is going to pick it up, build a new build box
+   image and push it to ghcr.io
 3. Then you can open another PR which starts using the new build box image.
 
 # DynamoDB static binary docker build
@@ -40,34 +40,3 @@ Or simply copy the binary out of the image using a volume (it will be copied to
 ```
 docker run -v $(pwd)/build:/builds -it teleportbuilder cp /gopath/src/github.com/gravitational/teleport/teleport.tgz /builds
 ```
-
-# OS package repo migrations
-
-An OS package repo migration is semi-manually publishing specific releases to the new APT and YUM repos. This is required in several situations:
-
-- A customer requests that we add an older version to the repos
-- We add another OS package repo (for example APK)
-- A OS package promotion fails (for example https://drone.platform.teleport.sh/gravitational/teleport/14666/1/3), requires a PR to fix, and we don't want to cut another minor version
-
-Multiple migrations can be performed at once. To run a migration do the following:
-
-1. Clone https://github.com/gravitational/teleport.git.
-2. Change to the directory the repo was cloned to.
-3. Create a new branch from master.
-4. Add the Teleport versions you wish to migration as demonstrated here: https://github.com/gravitational/teleport/commit/151a2f489e3116fc7ce8f55e056529361d3233a6#diff-2e3a64c97d186491e06fb2c7ead081b7ace2b67c4a4d974a563daf7c117a2c50.
-5. Set the `migrationBranch` variable to the name of the branch you created in (3) as demonstrated here: https://github.com/gravitational/teleport/commit/151a2f489e3116fc7ce8f55e056529361d3233a6#diff-2e3a64c97d186491e06fb2c7ead081b7ace2b67c4a4d974a563daf7c117a2c50.
-6. Get your Drone credentials from here: https://drone.platform.teleport.sh/account.
-7. Export your drone credentials as shown under "Example CLI Usage" on the Drone account page
-8. Open a new terminal.
-9. Run `tsh apps login drone` and follow any prompts.
-10. Run `tsh proxy app drone` and copy the printed socket. This should look something like `127.0.0.1:60982`
-11. Switch back to your previous terminal.
-12. Run `export DRONE_SERVER=http://{host:port}`, replacing `{host:port}` with the data you copied in (10)
-13. Run `make dronegen`
-14. Commit the two changed files and push/publish the branch
-15. Open a PR merging your changes into master via https://github.com/gravitational/teleport/compare
-16. Under the "checks" section, click "details" on the check labeled "continuous-integration/drone/push"
-17. Once the pipelines complete, comment out the versions you added and blank out the `migrationBranch` string set in (4, 5) as demonstrated here: https://github.com/gravitational/teleport/pull/15531/commits/9095880560cfe6c93e491e39a7604b1faf72c600#diff-2e3a64c97d186491e06fb2c7ead081b7ace2b67c4a4d974a563daf7c117a2c50
-18. Run `make dronegen`
-19. Commit and push the changes.
-20. Merge the PR and backport if required.

build.assets/images.mk

@@ -1,7 +1,5 @@
 # Those variables are extracted from build.assets/Makefile so they can be imported
 # by other Makefiles
-# These values may need to be updated in `dronegen/container_image_products.go` if
-# they change here
 ifeq ($(origin RUNTIME_ARCH), undefined)
 DIR := $(dir $(lastword $(MAKEFILE_LIST)))
 include $(DIR)arch.mk

docs/postrelease.md

@@ -18,8 +18,6 @@ is published, since the PR will include an update to the plugins version as well
 ### Major releases only
 
 - [ ] Update support matrix in docs FAQ page
-- [ ] Update `branchMajorVersion` const in Dronegen `/dronegen/container_images.go`, then run `make dronegen`
-- [ ] Update `CURRENT_VERSION_ROOT`, `PREVIOUS_VERSION_ONE_ROOT`, and `PREVIOUS_VERSION_TWO_ROOT` variables in `.drone.yml`, then run `make dronegen`
   - Example: https://github.com/gravitational/teleport/pull/4602
 - [ ] Create PR to update default Teleport image referenced in docker/teleport-quickstart.yml
   - Example: https://github.com/gravitational/teleport/pull/4655

docs/preflight.md

@@ -12,6 +12,4 @@ This checklist is to be run prior to cutting the release branch.
 - [ ] Update docs/faq.mdx "Which version of Teleport is supported?" section with release date and support info
 - [ ] Update the CI buildbox image
   - [ ] Update the `BUILDBOX_VERSION` in `build.assets/images.mk`
-  - [ ] Run `make dronegen` and ensure _all_ buildbox references in the resulting yaml refer to the new image
-  - [ ] Commit and merge. Drone should build new buildbox images and push to
-    `public.ecr.aws`
+  - [ ] Commit and merge. GitHub Actions should build new buildbox images and push to `ghcr.io`