Merge pull request #391 from brancz/alerting

assets/alertmanager/alertmanager.yaml

assets/prometheus/rules/alertmanager.rules

assets/prometheus/rules/etcd2.rules

assets/prometheus/rules/etcd3.rules

assets/prometheus/rules/general.rules

assets/prometheus/rules/kube-apiserver.rules

assets/prometheus/rules/kube-controller-manager.rules

assets/prometheus/rules/kube-scheduler.rules

assets/prometheus/rules/kubelet.rules

assets/prometheus/rules/kubernetes.rules

assets/prometheus/rules/node.rules

assets/prometheus/rules/prometheus.rules

manifests/alertmanager/alertmanager-config.yaml

manifests/examples/example-app/prometheus-frontend.yaml

...ests/prometheus-operator/prometheus-operator-service.yaml

manifests/prometheus-operator/prometheus-operator.yaml

manifests/prometheus/prometheus-k8s-rules.yaml

...ometheus/prometheus-k8s-service-monitor-alertmanager.yaml

.../prometheus/prometheus-k8s-service-monitor-apiserver.yaml

...ometheus-k8s-service-monitor-kube-controller-manager.yaml