垂直 Pod 自动缩放（Vertical Pod Autoscaling，VPA）通过自动配置资源需求降低维护成本并提高集群资源利用率。
VPA 模式
VPAs 有四种操作模式：
Auto：VPA 在创建 pod 时分配资源请求，使用首选的更新机制更新现有 pod 的资源请求。目前，这相当于“Recreate”（见下文）。一旦在不重启（“in-place”）更新 pod 请求方面可用，它可能会成为“Auto”模式的首选更新机制。注意：此 VPA 功能是实验性的，可能会导致你的应用停机。Recreate：VPA 在创建 pod 时分配资源请求，并在请求的资源与新建议显著不同时将其从现有 pod 中驱逐出来（如果定义了 Pod Disruption Budget，则会尊重它）。只有在需要确保每当资源请求更改时都重启 pod 时才应使用此模式。否则，请优先考虑“Auto”模式，一旦可用，该模式可以利用不重启更新。注意：此 VPA 功能是实验性的，可能会导致你的应用停机。Initial：VPA 仅在创建 pod 时分配资源请求，从不更改它们。Off：VPA 不会自动更改 pod 的资源要求。建议计算并可以在 VPA 对象中进行检查。
示例
以下是使用 Argo-Rollouts 的垂直 Pod 自动缩放器的示例。
Rollout 示例应用程序：
apiVersion: argoproj.io/v1alpha1
kind: Rollout
metadata:
name: vpa-demo-rollout
namespace: test-vpa
spec:
replicas: 5
strategy:
canary:
steps:
- setWeight: 20
- pause: {duration: 10}
- setWeight: 40
- pause: {duration: 10}
- setWeight: 60
- pause: {duration: 10}
- setWeight: 80
- pause: {duration: 10}
revisionHistoryLimit: 10
selector:
matchLabels:
app: vpa-demo-rollout
template:
metadata:
labels:
app: vpa-demo-rollout
spec:
containers:
- name: vpa-demo-rollout
image: ravihari/nginx:v1
ports:
- containerPort: 80
resources:
requests:
cpu: "5m"
memory: "5Mi"
Rollout 示例应用程序的 VPA 配置：
apiVersion: "autoscaling.k8s.io/v1beta2"
kind: VerticalPodAutoscaler
metadata:
name: vpa-rollout-example
namespace: test-vpa
spec:
targetRef:
apiVersion: "argoproj.io/v1alpha1"
kind: Rollout
name: vpa-demo-rollout
updatePolicy:
updateMode: "Auto"
resourcePolicy:
containerPolicies:
- containerName: '*'
minAllowed:
cpu: 5m
memory: 5Mi
maxAllowed:
cpu: 1
memory: 500Mi
controlledResources: ["cpu", "memory"]
最初部署时描述 VPA 时，我们不会看到推荐，因为它需要几分钟时间才能完成。
Name: kubengix-vpa
Namespace: test-vpa
Labels: <none>
Annotations: <none>
API Version: autoscaling.k8s.io/v1
Kind: VerticalPodAutoscaler
Metadata:
Creation Timestamp: 2022-03-14T12:54:06Z
Generation: 1
Managed Fields:
API Version: autoscaling.k8s.io/v1beta2
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:resourcePolicy:
.:
f:containerPolicies:
f:targetRef:
.:
f:apiVersion:
f:kind:
f:name:
f:updatePolicy:
.:
f:updateMode:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2022-03-14T12:54:06Z
Resource Version: 3886
UID: 4ac64e4c-c84b-478e-92e4-5f072f985971
Spec:
Resource Policy:
Container Policies:
Container Name: *
Controlled Resources:
cpu
memory
Max Allowed:
Cpu: 1
Memory: 500Mi
Min Allowed:
Cpu: 5m
Memory: 5Mi
Target Ref:
API Version: argoproj.io/v1alpha1
Kind: Rollout
Name: vpa-demo-rollout
Update Policy:
Update Mode: Auto
Events: <none>
几分钟后，VPA 开始处理并提供建议：
Name: kubengix-vpa
Namespace: test-vpa
Labels: <none>
Annotations: <none>
API Version: autoscaling.k8s.io/v1
Kind: VerticalPodAutoscaler
Metadata:
Creation Timestamp: 2022-03-14T12:54:06Z
Generation: 2
Managed Fields:
API Version: autoscaling.k8s.io/v1beta2
Fields Type: FieldsV1
fieldsV1:
f:metadata:
f:annotations:
.:
f:kubectl.kubernetes.io/last-applied-configuration:
f:spec:
.:
f:resourcePolicy:
.:
f:containerPolicies:
f:targetRef:
.:
f:apiVersion:
f:kind:
f:name:
f:updatePolicy:
.:
f:updateMode:
Manager: kubectl-client-side-apply
Operation: Update
Time: 2022-03-14T12:54:06Z
API Version: autoscaling.k8s.io/v1
Fields Type: FieldsV1
fieldsV1:
f:status:
.:
f:conditions:
f:recommendation:
.:
f:containerRecommendations:
Manager: recommender
Operation: Update
Time: 2022-03-14T12:54:52Z
Resource Version: 3950
UID: 4ac64e4c-c84b-478e-92e4-5f072f985971
Spec:
Resource Policy:
Container Policies:
Container Name: *
Controlled Resources:
cpu
memory
Max Allowed:
Cpu: 1
Memory: 500Mi
Min Allowed:
Cpu: 5m
Memory: 5Mi
Target Ref:
API Version: argoproj.io/v1alpha1
Kind: Rollout
Name: vpa-demo-rollout
Update Policy:
Update Mode: Auto
Status:
Conditions:
Last Transition Time: 2022-03-14T12:54:52Z
Status: True
Type: RecommendationProvided
Recommendation:
Container Recommendations:
Container Name: vpa-demo-rollout
Lower Bound:
Cpu: 25m
Memory: 262144k
Target:
Cpu: 25m
Memory: 262144k
Uncapped Target:
Cpu: 25m
Memory: 262144k
Upper Bound:
Cpu: 1
Memory: 500Mi
Events: <none>
在这里，我们可以看到 CPU、内存的建议，以及较低的界限、较高的界限、目标等等。如果我们检查 Pod 的状态，旧的 Pod 会被终止，新的 Pod 会被创建。
# kubectl get po -n test-vpa -w
NAME READY STATUS RESTARTS AGE
vpa-demo-rollout-f5df6d577-65f26 1/1 Running 0 17m
vpa-demo-rollout-f5df6d577-d55cx 1/1 Running 0 17m
vpa-demo-rollout-f5df6d577-fdpn2 1/1 Running 0 17m
vpa-demo-rollout-f5df6d577-jg2pw 1/1 Running 0 17m
vpa-demo-rollout-f5df6d577-vlx5x 1/1 Running 0 17m
...
vpa-demo-rollout-f5df6d577-jg2pw 1/1 Terminating 0 17m
vpa-demo-rollout-f5df6d577-vlx5x 1/1 Terminating 0 17m
vpa-demo-rollout-f5df6d577-jg2pw 0/1 Terminating 0 18m
vpa-demo-rollout-f5df6d577-vlx5x 0/1 Terminating 0 18m
vpa-demo-rollout-f5df6d577-w7tx4 0/1 Pending 0 0s
vpa-demo-rollout-f5df6d577-w7tx4 0/1 Pending 0 0s
vpa-demo-rollout-f5df6d577-w7tx4 0/1 ContainerCreating 0 0s
vpa-demo-rollout-f5df6d577-vdlqq 0/1 Pending 0 0s
vpa-demo-rollout-f5df6d577-vdlqq 0/1 Pending 0 1s
vpa-demo-rollout-f5df6d577-jg2pw 0/1 Terminating 0 18m
vpa-demo-rollout-f5df6d577-jg2pw 0/1 Terminating 0 18m
vpa-demo-rollout-f5df6d577-vdlqq 0/1 ContainerCreating 0 1s
vpa-demo-rollout-f5df6d577-w7tx4 1/1 Running 0 6s
vpa-demo-rollout-f5df6d577-vdlqq 1/1 Running 0 7s
vpa-demo-rollout-f5df6d577-vlx5x 0/1 Terminating 0 18m
vpa-demo-rollout-f5df6d577-vlx5x 0/1 Terminating 0 18m
如果我们检查新的 Pod CPU 和内存，它们会根据 VPA 的建议进行更新：
# kubectl describe po vpa-demo-rollout-f5df6d577-vdlqq -n test-vpa
Name: vpa-demo-rollout-f5df6d577-vdlqq
Namespace: test-vpa
Priority: 0
Node: argo-rollouts-control-plane/172.18.0.2
Start Time: Mon, 14 Mar 2022 12:55:06 +0000
Labels: app=vpa-demo-rollout
rollouts-pod-template-hash=f5df6d577
Annotations: vpaObservedContainers: vpa-demo-rollout
vpaUpdates: Pod resources updated by kubengix-vpa: container 0: cpu request, memory request
Status: Running
IP: 10.244.0.17
IPs:
IP: 10.244.0.17
Controlled By: ReplicaSet/vpa-demo-rollout-f5df6d577
Containers:
vpa-demo-rollout:
Container ID: containerd://b79bd88851fe0622d33bc90a1560ca54ef2c27405a3bc9a4fc3a333eef5f9733
Image: ravihari/nginx:v1
Image ID: docker.io/ravihari/nginx@sha256:205961b09a80476af4c2379841bf6abec0022101a7e6c5585a88316f7115d17a
Port: 80/TCP
Host Port: 0/TCP
State: Running
Started: Mon, 14 Mar 2022 12:55:11 +0000
Ready: True
Restart Count: 0
Requests:
cpu: 25m
memory: 262144k
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-mk4fz (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-mk4fz:
Type: Projected (a volume that contains injected data from multiple sources)
TokenExpirationSeconds: 3607
ConfigMapName: kube-root-ca.crt
ConfigMapOptional: <nil>
DownwardAPI: true
QoS Class: Burstable
Node-Selectors: <none>
Tolerations: node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
Type Reason Age From Message
---- ------ ---- ---- -------
Normal Scheduled 38s default-scheduler Successfully assigned test-vpa/vpa-demo-rollout-f5df6d577-vdlqq to argo-rollouts-control-plane
Normal Pulled 35s kubelet Container image "ravihari/nginx:v1" already present on machine
Normal Created 35s kubelet Created container vpa-demo-rollout
Normal Started 33s kubelet Started container vpa-demo-rollout
要求
为了让 VPA 操纵 Rollout，托管 Rollout CRD 的 Kubernetes 集群需要支持 CRD 的子资源。这个功能在 Kubernetes 1.10 版本中引入了 alpha，并在 Kubernetes 1.11 版本中转换为 beta。如果用户想在 v1.10 上使用 VPA，则 Kubernetes 集群操作员需要向 API 服务器添加自定义功能标志。1.10 之后，该标志默认为开启状态。请查看以下链接以获取有关设置自定义功能标志的更多信息。
安装 VPA 时，你可能需要将以下内容添加到 RBAC 配置中，以便为 system:vpa-target-reader 集群角色添加支持，因为默认情况下 VPA 可能不支持所有版本的 Rollout。
- apiGroups:
- argoproj.io
resources:
- rollouts
- rollouts/scale
- rollouts/status
- replicasets
verbs:
- get
- list
- watch
确保在集群中安装了 Metrics-Server，并且 openssl 更新到最新版本，以便 VPA 的最新版本能够正确地将建议应用于 Pod。