Expose DOCKER_USERNS_REMAP to global environment hook

The environment hook is using this variable to decide if fix-buildkite-agent-builds-permissions needs to be run.

Author: rianmcguire

packer/linux/conf/bin/bk-install-elastic-stack.sh

@@ -141,6 +141,7 @@ set_always         "BUILDKITE_SECRETS_BUCKET_REGION" "$BUILDKITE_SECRETS_BUCKET_
 set_always         "BUILDKITE_STACK_NAME" "$BUILDKITE_STACK_NAME"
 set_always         "BUILDKITE_STACK_VERSION" "$BUILDKITE_STACK_VERSION"
 set_always         "BUILDKITE_DOCKER_EXPERIMENTAL" "$DOCKER_EXPERIMENTAL"
+set_always         "DOCKER_USERNS_REMAP" "$DOCKER_USERNS_REMAP"
 set_always         "DOCKER_VERSION" "$DOCKER_VERSION"
 set_always         "PLUGINS_ENABLED" "${PLUGINS_ENABLED[*]-}"
 set_unless_present "AWS_DEFAULT_REGION" "$AWS_REGION"

templates/aws-stack.yml

@@ -1302,6 +1302,7 @@ Resources:
                   ECR_PLUGIN_ENABLED="${EnableECRPlugin}" \
                   DOCKER_LOGIN_PLUGIN_ENABLED="${EnableDockerLoginPlugin}" \
                   DOCKER_EXPERIMENTAL="${EnableDockerExperimental}" \
+                  DOCKER_USERNS_REMAP=${EnableDockerUserNamespaceRemap} \
                   AWS_REGION="${AWS::Region}" \
                     /usr/local/bin/bk-install-elastic-stack.sh
                   --==BOUNDARY==--