1 /* 2 Copyright 2016 The Kubernetes Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 // Package antiaffinity provides the LimitPodHardAntiAffinityTopology 18 // admission controller. It rejects any pod that specifies "hard" 19 // (RequiredDuringScheduling) anti-affinity with a TopologyKey other 20 // than v1.LabelHostname. Because anti-affinity is symmetric, without 21 // this admission controller, a user could maliciously or accidentally 22 // specify that their pod (once it has scheduled) should block other 23 // pods from scheduling into the same zone or some other large 24 // topology, essentially DoSing the cluster. In the future we will 25 // address this problem more fully by using quota and priority, but 26 // for now this admission controller provides a simple protection, on 27 // the assumption that the only legitimate use of hard pod 28 // anti-affinity is to exclude other pods from the same node. 29 package antiaffinity // import "k8s.io/kubernetes/plugin/pkg/admission/antiaffinity" 30