5 個 Istio 訪問外部服務的流量控制常用例子,強烈建議收藏起來,以備不時之需。
環境準備
部署 sleep
服務,作爲發送請求的測試源:
kubectl apply -f samples/sleep/sleep.yaml
在 Istio 外部,使用 Nginx 搭建 duckling
服務的v1和v2兩個版本,訪問時顯示簡單的文本:
> curl -s http://192.168.1.118/
This is the v1 version of duckling.
> curl -s http://192.168.1.119/
This is the v2 version of duckling.
訪問外部服務
執行如下命名訪問外部服務 httpbin.org :
export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://httpbin.org/headers
返回結果如下:
{
"headers": {
"Accept": "*/*",
"Host": "httpbin.org",
"User-Agent": "curl/7.81.0-DEV",
"X-Amzn-Trace-Id": "Root=1-62bbfa10-3237e3b9662c65ae005148ab",
"X-B3-Sampled": "0",
"X-B3-Spanid": "9e650093bf7ae862",
"X-B3-Traceid": "1da46d7fafa5d71c9e650093bf7ae862",
"X-Envoy-Attempt-Count": "1",
"X-Envoy-Peer-Metadata": "......",
"X-Envoy-Peer-Metadata-Id": "sidecar~......"
}
}
此時的方法,沒有通過Service Entry,沒有 Istio 的流量監控和控制特性。創建 Service Entry :
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
name: httpbin-ext
spec:
hosts:
- httpbin.org
ports:
- number: 80
name: http
protocol: HTTP
resolution: DNS
location: MESH_EXTERNAL
EOF
再此次訪問,返回結果如下:
{
"headers": {
"Accept": "*/*",
"Host": "httpbin.org",
"User-Agent": "curl/7.81.0-DEV",
"X-Amzn-Trace-Id": "Root=1-62bbfbd6-254b05344b3cde2c0c41b3b8",
"X-B3-Sampled": "0",
"X-B3-Spanid": "307c0b106c8b262e",
"X-B3-Traceid": "f684a50776c088ac307c0b106c8b262e",
"X-Envoy-Attempt-Count": "1",
"X-Envoy-Decorator-Operation": "httpbin.org:80/*",
"X-Envoy-Peer-Metadata": "......",
"X-Envoy-Peer-Metadata-Id": "sidecar~......"
}
}
可以發現由 Istio 邊車添加的請求頭:X-Envoy-Decorator-Operation
。
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設置請求超時
向外部服務 httpbin.org 的 /delay 發出請求:
export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- time curl -o /dev/null -sS -w "%{http_code}\n" http://httpbin.org/delay/5
返回結果如下:
200
real 0m 5.69s
user 0m 0.00s
sys 0m 0.00s
請求大約在 5 秒後返回 200 (OK)。
創建虛擬服務,訪問外部服務 httpbin.org 時, 請求超時設置爲 3 秒:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin-ext
spec:
hosts:
- httpbin.org
http:
- timeout: 3s
route:
- destination:
host: httpbin.org
weight: 100
EOF
再此次訪問,返回結果如下:
504
real 0m 3.01s
user 0m 0.00s
sys 0m 0.00s
可以看出,在 3 秒後出現了 504 (Gateway Timeout)。 Istio 在 3 秒後切斷了響應時間爲 5 秒的 httpbin.org 服務。
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注入 HTTP 延遲故障
向外部服務 httpbin.org 的 /get 發出請求:
export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- time curl -o /dev/null -sS -w "%{http_code}\n" http://httpbin.org/get
返回結果如下:
200
real 0m 0.45s
user 0m 0.00s
sys 0m 0.00s
請求不到 1 秒就返回 200 (OK)。
創建虛擬服務,訪問外部服務 httpbin.org 時, 注入一個 3 秒的延遲:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin-ext
spec:
hosts:
- httpbin.org
http:
- fault:
delay:
fixedDelay: 3s
percentage:
value: 100
route:
- destination:
host: httpbin.org
EOF
再此次訪問 httpbin.org 的 /get ,返回結果如下:
200
real 0m 3.43s
user 0m 0.00s
sys 0m 0.00s
可以看出,在 3 秒後出現了 200 (OK)。
流量轉移
訪問duckling
服務時,所有流量都路由到v1版本,具體配置如下:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
name: duckling
spec:
hosts:
- duckling.com
ports:
- number: 80
name: http
protocol: HTTP
location: MESH_EXTERNAL
resolution: STATIC
endpoints:
- address: 172.24.29.118
ports:
http: 80
labels:
version: v1
- address: 172.24.29.119
ports:
http: 80
labels:
version: v2
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: duckling
spec:
hosts:
- duckling.com
http:
- route:
- destination:
host: duckling.com
subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: duckling
spec:
host: duckling.com
subsets:
- labels:
version: v1
name: v1
- labels:
version: v2
name: v2
EOF
執行如下命名訪問外部服務 duckling.com :
export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://duckling.com/
多次訪問後,返回結果一直是:This is the v1 version of duckling.
訪問duckling
服務時,把50%流量轉移到v2版本,具體配置如下:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: duckling
spec:
hosts:
- duckling.com
http:
- route:
- destination:
host: duckling.com
subset: v1
weight: 50
- destination:
host: duckling.com
subset: v2
weight: 50
EOF
多次訪問外部服務 duckling.com ,有時返回This is the v1 version of duckling.
,有時返回This is the v2 version of duckling.
。
訪問duckling
服務時,所有流量都路由到v2版本,具體配置如下:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: duckling
spec:
hosts:
- duckling.com
http:
- route:
- destination:
host: duckling.com
subset: v2
EOF
多次訪問外部服務 duckling.com ,一直返回This is the v2 version of duckling.
。
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基於請求頭的路由
請求頭end-user
爲OneMore的所有流量都路由到v2版本,其他流量都路由到v1版本,具體配置如下:
kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: ServiceEntry
metadata:
name: duckling
spec:
hosts:
- duckling.com
ports:
- number: 80
name: http
protocol: HTTP
location: MESH_EXTERNAL
resolution: STATIC
endpoints:
- address: 172.24.29.118
ports:
http: 80
labels:
version: v1
- address: 172.24.29.119
ports:
http: 80
labels:
version: v2
---
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: duckling
spec:
hosts:
- duckling.com
http:
- match:
- headers:
end-user:
exact: OneMore
route:
- destination:
host: duckling.com
subset: v2
- route:
- destination:
host: duckling.com
subset: v1
---
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: duckling
spec:
host: duckling.com
subsets:
- labels:
version: v1
name: v1
- labels:
version: v2
name: v2
EOF
執行如下命名訪問外部服務 duckling.com :
export SLEEP_POD=$(kubectl get pods -l app=sleep -o 'jsonpath={.items[0].metadata.name}')
kubectl exec "$SLEEP_POD" -c sleep -- curl -s http://duckling.com/
多次訪問的返回結果一直是:This is the v1 version of duckling.
設置請求頭end-user
爲OneMore,訪問外部服務 duckling.com :
kubectl exec "$SLEEP_POD" -c sleep -- curl -H "end-user:OneMore" -s http://duckling.com/
多次訪問的返回結果一直是:This is the v2 version of duckling.
最後,感謝你這麼帥,還給我點贊。
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