kubernetes - 启用 ExpandPersistentVolumes

Question

我需要调整一堆 PVC 的大小。似乎最简单的方法是通过ExpandPersistentVolumes 功能。但是我无法获得配置合作。

ExpandPersistentVolumes feature gate 在 kubelet 中设置在所有三个masters，如图:

(输出修剪到相关位以保持理智)

$ parallel-ssh -h /tmp/masters -P "ps aux | grep feature"
172.20.53.249: root     15206  7.4  0.5 619888 83952 ?        Ssl  19:52   0:02 /opt/kubernetes/bin/kubelet  --feature-gates=ExpandPersistentVolumes=true,ExperimentalCriticalPodAnnotation=true
[1] 12:53:08 [SUCCESS] 172.20...
172.20.58.111: root     17798  4.5  0.5 636280 87328 ?        Ssl  19:51   0:04 /opt/kubernetes/bin/kubelet --feature-gates=ExpandPersistentVolumes=true,ExperimentalCriticalPodAnnotation=true
[2] 12:53:08 [SUCCESS] 172.20...
172.20.53.240: root      9287  4.0  0.5 645276 90528 ?        Ssl  19:50   0:06 /opt/kubernetes/bin/kubelet --feature-gates=ExpandPersistentVolumes=true,ExperimentalCriticalPodAnnotation=true
[3] 12:53:08 [SUCCESS] 172.20..

apiserver 有 PersistentVolumeClaimResize 准入 Controller ，如图所示:

$ kubectl --namespace=kube-system get pod -o yaml | grep -i admission                                                                                                                                                           
    /usr/local/bin/kube-apiserver --admission-control=Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,NodeRestriction,PersistentVolumeClaimResize,ResourceQuota
    /usr/local/bin/kube-apiserver --admission-control=Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,NodeRestriction,PersistentVolumeClaimResize,ResourceQuota
    /usr/local/bin/kube-apiserver --admission-control=Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,NodeRestriction,PersistentVolumeClaimResize,ResourceQuota

但是，当我创建或编辑存储类以添加 allowVolumeExpansion 时，它在保存时被删除。例如:

$ cat new-sc.yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  creationTimestamp: null
  labels:
    k8s-addon: storage-aws.addons.k8s.io
  name: gp2-2
  selfLink: /apis/storage.k8s.io/v1/storageclasses/gp2
parameters:
  encrypted: "true"
  kmsKeyId: arn:aws:kms:us-west-2:<omitted>
  type: gp2
  zone: us-west-2a
provisioner: kubernetes.io/aws-ebs
reclaimPolicy: Delete
allowVolumeExpansion: true

$ kubectl create -f new-sc.yaml
storageclass "gp2-2" created

$ kubectl get sc gp2-2 -o yaml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  creationTimestamp: 2018-05-22T20:00:17Z
  labels:
    k8s-addon: storage-aws.addons.k8s.io
  name: gp2-2
  resourceVersion: "2546166"
  selfLink: /apis/storage.k8s.io/v1/storageclasses/gp2-2
  uid: <omitted>
parameters:
  encrypted: "true"
  kmsKeyId: arn:aws:kms:us-west-2:<omitted>
  type: gp2
  zone: us-west-2a
provisioner: kubernetes.io/aws-ebs
reclaimPolicy: Delete

我错过了什么？什么正在从我的存储类配置中删除此 key ？

编辑:这是 kube-apiserver pod 使用的命令。它没有说任何关于特征门的事情。该集群是使用 Kops 启动的。

- /bin/sh
    - -c
    - mkfifo /tmp/pipe; (tee -a /var/log/kube-apiserver.log < /tmp/pipe & ) ; exec
      /usr/local/bin/kube-apiserver --address=127.0.0.1 --admission-control=Initializers,NamespaceLifecycle,LimitRanger,ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,NodeRestriction,PersistentVolumeClaimResize,ResourceQuota
      --allow-privileged=true --anonymous-auth=false --apiserver-count=3 --authorization-mode=RBAC
      --basic-auth-file=/srv/kubernetes/basic_auth.csv --client-ca-file=/srv/kubernetes/ca.crt
      --cloud-provider=aws --etcd-cafile=/srv/kubernetes/ca.crt --etcd-certfile=/srv/kubernetes/etcd-client.pem
      --etcd-keyfile=/srv/kubernetes/etcd-client-key.pem --etcd-servers-overrides=/events#https://127.0.0.1:4002
      --etcd-servers=https://127.0.0.1:4001 --insecure-port=8080 --kubelet-preferred-address-types=InternalIP,Hostname,ExternalIP
      --proxy-client-cert-file=/srv/kubernetes/apiserver-aggregator.cert --proxy-client-key-file=/srv/kubernetes/apiserver-aggregator.key
      --requestheader-allowed-names=aggregator --requestheader-client-ca-file=/srv/kubernetes/apiserver-aggregator-ca.cert
      --requestheader-extra-headers-prefix=X-Remote-Extra- --requestheader-group-headers=X-Remote-Group
      --requestheader-username-headers=X-Remote-User --secure-port=443 --service-cluster-ip-range=100.64.0.0/13
      --storage-backend=etcd3 --tls-cert-file=/srv/kubernetes/server.cert --tls-private-key-file=/srv/kubernetes/server.key
      --token-auth-file=/srv/kubernetes/known_tokens.csv --v=1 > /tmp/pipe 2>&1

Answer 1

如果您没有为该选项启用 alpha feature-gate，则可能会发生这种情况。

您是否为 kube-apiserver 设置了 --feature-gates 选项？ ？

--feature-gates mapStringBool  - A set of key=value pairs that describe feature gates for alpha/experimental features. Options are:
...
ExpandPersistentVolumes=true|false (ALPHA - default=false)
...

更新:如果您在命令行参数中没有看到此选项，则需要添加它 (--feature-gates=ExpandPersistentVolumes=true)。

如果您将 kube-apiserver 作为 pod 运行，您应该编辑/etc/kubernetes/manifests/kube-apiserver.yaml 并将 feature-gate 选项添加到其他参数。 kube-apiserver 会自动重启。

如果您将 kube-apiserver 作为由 systemd 维护的进程运行，您应该在单独的文件中编辑 kube-apiserver.service 或服务选项 $KUBE_API_ARGS，并且在那里附加功能门选项。使用 systemctl restart kube-apiserver.service 命令重启服务。

启用后，您可以使用 allowVolumeExpansion 选项创建一个 StorageClass 对象:

# kubectl get sc -o yaml --export
apiVersion: v1
items:
- allowVolumeExpansion: true
  apiVersion: storage.k8s.io/v1
  kind: StorageClass
  metadata:
    creationTimestamp: 2018-05-23T14:38:43Z
    labels:
      k8s-addon: storage-aws.addons.k8s.io
    name: gp2-2
    namespace: ""
    resourceVersion: "1385"
    selfLink: /apis/storage.k8s.io/v1/storageclasses/gp2-2
    uid: fe516dcf-5e96-11e8-a86d-42010a9a0002
  parameters:
    encrypted: "true"
    kmsKeyId: arn:aws:kms:us-west-2:<omitted>
    type: gp2
    zone: us-west-2a
  provisioner: kubernetes.io/aws-ebs
  reclaimPolicy: Delete
  volumeBindingMode: Immediate
kind: List
metadata:
  resourceVersion: ""
  selfLink: ""