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本文主要研究一下如何变更pod的流量路由
配置
代码语言：javascript复制# Copyright Istio Authors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
##################################################################################################
# Ratings service
##################################################################################################
apiVersion: v1
kind: Service
metadata:
name: ratings
labels:
app: ratings
service: ratings
spec:
ports:
- port: 8080
name: http
selector:
app: ratings
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: ratings-v1
labels:
app: ratings
version: v1
spec:
replicas: 3
selector:
matchLabels:
app: ratings
version: v1
template:
metadata:
labels:
app: ratings
version: v1
spec:
containers:
- name: ratings
image: jvm-tools-demo
imagePullPolicy: IfNotPresent
ports:
- containerPort: 8080
securityContext:
runAsUser: 1000
resources:
# keep request = limit to keep this container in guaranteed class
requests:
cpu: 50m
memory: 128Mi
---kind load docker-image jvm-tools-demo kind create -f ratings.yaml
查看
endpoint
代码语言：javascript复制kubectl get ep
NAME ENDPOINTS AGE
kubernetes 192.168.228.2:6443 43m
ratings 10.244.0.10:8080,10.244.0.8:8080,10.244.0.9:8080 6m18ssvc
代码语言：javascript复制kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 46m
ratings ClusterIP 10.96.170.159 <none> 8080/TCP 9m3spods
代码语言：javascript复制kubectl get pods
NAME READY STATUS RESTARTS AGE
ratings-v1-676f4d994-8xp7j 1/1 Running 0 9m22s
ratings-v1-676f4d994-9gbkh 1/1 Running 0 9m22s
ratings-v1-676f4d994-tg49h 1/1 Running 0 9m22s更新label
代码语言：javascript复制kubectl label pod ratings-v1-676f4d994-tg49h app=ratings2 --overwrite查看变更
代码语言：javascript复制kubectl describe pod ratings-v1-676f4d994-tg49h
Name: ratings-v1-676f4d994-tg49h
Namespace: default
Priority: 0
Service Account: default
Node: kind-control-plane/192.168.228.2
Start Time: Tue, 13 Feb 2024 10:27:11 0800
Labels: app=ratings2
pod-template-hash=676f4d994
version=v1
Annotations: <none>
Status: Running
IP: 10.244.0.8
IPs:
IP: 10.244.0.8
Containers:
ratings:
Container ID: containerd://fe1d8ddc2d27c557a51181f0b4df8187fb1c06c71d8e564fe9f1ceebb480e156
Image: registry.cn-hangzhou.aliyuncs.com/springcloud-cn/jvm-tools-demo
Image ID: docker.io/library/import-2024-02-13@sha256:4ed39c8b931585c67e28def544117913fddf929cff8c3062ae19c3d15fffebe7
Port: 8080/TCP
Host Port: 0/TCP
State: Running
Started: Tue, 13 Feb 2024 10:27:12 0800
Ready: True
Restart Count: 0
Requests:
cpu: 50m
memory: 128Mi
Environment: <none>
Mounts:
/var/run/secrets/kubernetes.io/serviceaccount from kube-api-access-2f9mt (ro)
Conditions:
Type Status
Initialized True
Ready True
ContainersReady True
PodScheduled True
Volumes:
kube-api-access-2f9mt:
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 5m42s default-scheduler Successfully assigned default/ratings-v1-676f4d994-tg49h to kind-control-plane
Normal Pulled 5m41s kubelet Container image "registry.cn-hangzhou.aliyuncs.com/springcloud-cn/jvm-tools-demo" already present on machine
Normal Created 5m41s kubelet Created container ratings
Normal Started 5m41s kubelet Started container ratings可以看到label变更了
查看ep
代码语言：javascript复制kubectl get ep
NAME ENDPOINTS AGE
kubernetes 192.168.228.2:6443 50m
ratings 10.244.0.10:8080,10.244.0.11:8080,10.244.0.9:8080 12m可以看到原来10.244.0.8:8080的pod由于label被更新了，所以被移除了，但因为需要保持3个副本，因而点多生成了一个pod(
10.244.0.11:8080)
查看pod
代码语言：javascript复制kubectl get pods
NAME READY STATUS RESTARTS AGE
ratings-v1-676f4d994-8xp7j 1/1 Running 0 13m
ratings-v1-676f4d994-9gbkh 1/1 Running 0 13m
ratings-v1-676f4d994-hpfg8 1/1 Running 0 9m6s
ratings-v1-676f4d994-tg49h 1/1 Running 0 13m可以看到由于ratings-v1-676f4d994-tg49h的label被更新了，因而又重新生成了一个pod
小结
通过更新pod的label可以将该pod从endpoint中移除，从而使得该pod不会被svc的流量路由到。但是因为更新了label，原来app=ratings需要保持3个副本，因而会重新创建一个pod来补充。
doc
- 使用kind在mac本地搭建k8s及istio
- istio流量路由小试牛刀
- Kubernetes之Label
