From http://ci.theforeman.org/job/packaging_build_deb_coreproject/arch=armv8,label=debian,os=xenial/3871/console

00:34:46 /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/.bin/webpack --config /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/config/webpack.config.js --bail

00:35:00 ModuleBuildError: Module build failed: TypeError: /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/webpack/assets/javascripts/react_app/components/hosts/PowerStatusContainer.js: this.labels.get is not a function
00:35:00     at Scope.getLabel (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/scope/index.js:473:24)
00:35:00     at Scope.hasLabel (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/scope/index.js:469:19)
00:35:00     at Scope.generateUid (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/scope/index.js:273:19)
00:35:00     at Scope.generateUidIdentifier (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/scope/index.js:260:30)
00:35:00     at Scope.generateUidIdentifierBasedOnNode (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/scope/index.js:361:17)
00:35:00     at run (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-plugin-transform-es2015-classes/lib/vanilla.js:137:30)
00:35:00     at PluginPass.ClassExpression (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-plugin-transform-es2015-classes/lib/index.js:48:60)
00:35:00     at newFn (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/visitors.js:276:21)
00:35:00     at NodePath._call (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:76:18)
00:35:00     at NodePath.call (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:48:17)
00:35:00     at NodePath.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:105:12)
00:35:00     at TraversalContext.visitQueue (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:150:16)
00:35:00     at TraversalContext.visitSingle (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:108:19)
00:35:00     at TraversalContext.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:192:19)
00:35:00     at Function.traverse.node (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/index.js:114:17)
00:35:00     at NodePath.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:115:19)
00:35:00     at TraversalContext.visitQueue (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:150:16)
00:35:00     at TraversalContext.visitMultiple (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:103:17)
00:35:00     at TraversalContext.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:190:19)
00:35:00     at Function.traverse.node (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/index.js:114:17)
00:35:00     at NodePath.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:115:19)
00:35:00     at TraversalContext.visitQueue (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:150:16)
00:35:00     at TraversalContext.visitQueue (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:156:21)
00:35:00     at TraversalContext.visitMultiple (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:103:17)
00:35:00     at TraversalContext.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:190:19)
00:35:00     at Function.traverse.node (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/index.js:114:17)
00:35:00     at NodePath.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/path/context.js:115:19)
00:35:00     at TraversalContext.visitQueue (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:150:16)
00:35:00     at TraversalContext.visitSingle (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:108:19)
00:35:00     at TraversalContext.visit (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/context.js:192:19)
00:35:00     at Function.traverse.node (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/babel-traverse/lib/index.js:114:17)
00:35:00     at DependenciesBlock.onModuleBuildFailed (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:315:19)
00:35:00     at nextLoader (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:270:31)
00:35:00     at /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:292:15
00:35:00     at runSyncOrAsync (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:173:4)
00:35:00     at nextLoader (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:290:3)
00:35:00     at /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/webpack-core/lib/NormalModuleMixin.js:259:5
00:35:00     at Storage.finished (/var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/enhanced-resolve/lib/CachedInputFileSystem.js:38:16)
00:35:00     at /var/lib/workspace/workspace/packaging_build_deb_coreproject/arch/armv8/label/debian/os/xenial/debian/xenial/build-foreman/foreman-1.14.0/node_modules/graceful-fs/graceful-fs.js:78:16
00:35:00     at FSReqWrap.readFileAfterClose [as oncomplete] (fs.js:380:3)

00:35:31 rake aborted!
00:35:31 Command failed with status (1): [/var/lib/workspace/workspace/packaging_bui...]
00:35:31 /var/lib/gems/2.3.0/gems/webpack-rails-0.9.9/lib/tasks/webpack.rake:17:in `block (2 levels) in <top (required)>'
00:35:31 /var/lib/gems/2.3.0/gems/rake-11.3.0/exe/rake:27:in `<top (required)>'
00:35:31 Tasks: TOP => webpack:compile

As the build succeeds on x86 and ARMv7, it's likely that this is an issue in nodejs (4.2.6~dfsg-1ubuntu4.1) or a part of the toolchain. Note that there are no nodesource packages for ARMv8, so that builder can not get simply updated.