前言
金丝雀部署的方式有很多种，istio只是其中一种选择， Kubernetes 这样的平台已经提供了进行版本上线和金丝雀部署的方法，但很多问题依然不能解决， 所以使用Istio作为金丝雀部署方案也是很好的选择
金丝雀部署首先部署好新版本，然后让一小部分用户流量引入的新版本进行测试，如果一切顺利，则可以调整比例替换旧版本。如在过程中出现问题，回滚到旧版本即可。最简单的方式，是随机选择百分比请求到金丝雀版本，在更复杂的方案下，可以基于请求的区域，用户或其他属性，本次我们只搞下简单方式。
实验思路和环境
流量从istio-ingressgateway进入，经过创建的gateway，读取VirtualService的流量分配，通过DestinationRule规则关联到pod
实验思路
1、准备两个deployment，设置两个lables，镜像使用nginx即可，为了区分版本，我们进入容器，手动修改一下默认页内容
2、创建svc，选择其中一个labels
3、创建istio gateway
4、创建VirtualService并根据subset分配流量占比
5、创建DestinationRule，设置subsets分别指定不同的lables
6、测试访问
k8s环境
[root@k8s-master istio-canary]# kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master Ready control-plane,master 41d v1.22.0
k8s-node01 Ready <none> 41d v1.22.0
k8s-node02 Ready <none> 41d v1.22.0istio环境
[root@k8s-master istio-canary]# kubectl get pod,svc -n istio-system
NAME READY STATUS RESTARTS AGE
pod/istio-egressgateway-687f4db598-s6l8v 1/1 Running 0 103m
pod/istio-ingressgateway-78f69bd5db-kcgzb 1/1 Running 0 47m
pod/istiod-76d66d9876-5wnf2 1/1 Running 0 115m
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
service/istio-egressgateway ClusterIP 10.108.16.157 <none> 80/TCP,443/TCP 3d23h
service/istio-ingressgateway LoadBalancer 10.99.29.225 <pending> 15021:30954/TCP,80:30869/TCP,443:32748/TCP,31400:31230/TCP,15443:30625/TCP 3d23h
service/istiod ClusterIP 10.109.41.38 <none> 15010/TCP,15012/TCP,443/TCP,15014/TCP 3d23h创建deployment
准备两个deployment，设置两个lables，镜像使用nginx，模拟不同版本的应用
[root@k8s-master istio-canary]# cat deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
name: appv1
labels:
app: v1
spec:
replicas: 1
selector:
matchLabels:
app: v1
apply: canary
template:
metadata:
labels:
app: v1
apply: canary
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: appv2
labels:
app: v2
spec:
replicas: 1
selector:
matchLabels:
app: v2
apply: canary
template:
metadata:
labels:
app: v2
apply: canary
spec:
containers:
- name: nginx
image: nginx
ports:
- containerPort: 80
---
[root@k8s-master istio-canary]# kubectl apply -f deployment.yaml
deployment.apps/appv1 created
deployment.apps/appv2 created为了区分两个版本的不通，我们可以修改默认页内容
[root@k8s-master istio-canary]# kubectl get pod
NAME READY STATUS RESTARTS AGE
appv1-5cf75d8d8b-vdvzr 2/2 Running 0 22m
appv2-684dd44db7-r6k6k 2/2 Running 0 22m
[root@k8s-master istio-canary]# kubectl exec appv1-5cf75d8d8b-vdvzr -it /bin/bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@appv1-5cf75d8d8b-vdvzr:/# echo v1 > /usr/share/nginx/html/index.html
root@appv1-5cf75d8d8b-vdvzr:/# exit
exit
[root@k8s-master istio-canary]# kubectl exec appv2-684dd44db7-r6k6k -it /bin/bash
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
root@appv2-684dd44db7-r6k6k:/# echo v2 > /usr/share/nginx/html/index.html修改后我们可以创建个svc，然后通过curl svc地址模拟访问一下，访问结果应该是轮询，各百分之50。
[root@k8s-master istio-canary]# cat service.yaml
apiVersion: v1
kind: Service
metadata:
name: canary
labels:
apply: canary
spec:
selector:
apply: canary
ports:
- protocol: TCP
port: 80
targetPort: 80
[root@k8s-master istio-canary]# kubectl apply -f service.yaml
service/canary created
[root@k8s-master istio-canary]# kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
canary ClusterIP 10.97.182.219 <none> 80/TCP 7s
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 3h11m
[root@k8s-master istio-canary]# curl 10.97.182.219
v2
[root@k8s-master istio-canary]# curl 10.97.182.219
v1
[root@k8s-master istio-canary]# curl 10.97.182.219
v2
[root@k8s-master istio-canary]# curl 10.97.182.219
v1
[root@k8s-master istio-canary]# curl 10.97.182.219
v2
[root@k8s-master istio-canary]# curl 10.97.182.219
v1
[root@k8s-master istio-canary]# curl 10.97.182.219
v2创建gateway
[root@k8s-master istio-canary]# cat gateway.yaml
apiVersion: networking.istio.io/v1beta1
kind: Gateway
metadata:
name: canary-gateway
spec:
selector:
istio: ingressgateway
servers:
- port:
number: 80
name: http
protocol: HTTP
hosts:
- "*"
[root@k8s-master istio-canary]# kubectl apply -f gateway.yaml
gateway.networking.istio.io/canary-gateway created
[root@k8s-master istio-canary]# kubectl get gateways.networking.istio.io
NAME AGE
canary-gateway 7s创建VirtualService和DestinationRule，其中hosts地址必须加上.cluster.local不然报503错误，查了好久，目前还没找到为啥简写不行，有知道的可以留言指导我一下
[root@k8s-master istio-canary]# cat virtualservice.yaml
apiVersion: networking.istio.io/v1beta1
kind: VirtualService
metadata:
name: canary
spec:
hosts:
- "*"
gateways:
- canary-gateway
http:
- match:
- uri:
prefix: /
route:
- destination:
host: canary.default.svc.cluster.local
subset: v1
weight: 90
- destination:
host: canary.default.svc.cluster.local
subset: v2
weight: 10
---
apiVersion: networking.istio.io/v1beta1
kind: DestinationRule
metadata:
name: canary
spec:
host: canary.default.svc.cluster.local
subsets:
- name: v1
labels:
app: v1
- name: v2
labels:
app: v2
[root@k8s-master istio-canary]# kubectl apply -f virtualservice.yaml
virtualservice.networking.istio.io/canary created
destinationrule.networking.istio.io/canary created到目前为止环境已经就绪，可以开始测试，因为流量是从istio-ingressgateway进入，所以需要先查看一下svc的入口，入口为LoadBlancer模式，此模式一般用于云厂商的负载均衡，我们也可以使用节点方式访问，80端口已经映射出了对应的端口30869
[root@k8s-master istio-canary]# kubectl get svc -n istio-system
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
istio-egressgateway ClusterIP 10.108.16.157 <none> 80/TCP,443/TCP 4d1h
istio-ingressgateway LoadBalancer 10.99.29.225 <pending> 15021:30954/TCP,80:30869/TCP,443:32748/TCP,31400:31230/TCP,15443:30625/TCP 4d1h
istiod ClusterIP 10.109.41.38 <none> 15010/TCP,15012/TCP,443/TCP,15014/TCP 4d1h
[root@k8s-master istio-canary]# curl 192.168.3.50:30869
v1
[root@k8s-master istio-canary]# curl 192.168.3.50:30869
v1
[root@k8s-master istio-canary]# curl 192.168.3.50:30869
v1
[root@k8s-master istio-canary]# curl 192.168.3.50:30869
v1
[root@k8s-master istio-canary]# curl 192.168.3.50:30869
v1通过手动curl测试效果并不好，因为访问的次数少，所以我们可以通过循环来访问
[root@k8s-master istio-canary]# for ((i=1;i<=100;i++)); do curl 192.168.3.50:30869; done结果太长不贴了，统计结果如下，大约是90：10
[root@k8s-master istio-canary]# cat /tmp/curl.txt |sort |uniq -c
89 v1
11 v2修改流量
[root@k8s-master istio-canary]# kubectl edit virtualservices.networking.istio.io canary
...
route:
- destination:
host: canary.default.svc.cluster.local
subset: v1
weight: 70 # 由90修改为70
- destination:
host: canary.default.svc.cluster.local
subset: v2
weight: 30 # 由10修改为30
...修改完之后再次执执行循环curl命令，统计结果信息如下
[root@k8s-master istio-canary]# for ((i=1;i<=100;i++)); do curl 192.168.3.50:30869; done > /tmp/curl.txt
[root@k8s-master istio-canary]# cat /tmp/curl.txt |sort |uniq -c
70 v1
30 v2
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