本章我们来讲讲如何通过istio来提升系统的弹性能力，弹性能力主要包含如下几个方面，我们今天看看如何用istio中的一些功能去解决这些问题。
- 容错性：重试、幂等
- 伸缩性：自动水平扩展（autoscaling）
- 过载保护：超时、熔断、降级、限流
- 弹性测试：故障注入
今天我们讲讲如何通过istio中的超时、重试、熔断、故障注入来提升服务的弹性能力。
首先我们通过VirtualService来暴露我们之前部署的httpbin服务
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| kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin
namespace: demo
spec:
hosts:
- "*"
gateways:
- httpbin-gateway
http:
- route:
- destination:
host: httpbin
port:
number: 8000
EOF
|
超时
首先我们给httpbin配置一个超时
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| apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin
namespace: demo
spec:
hosts:
- "*"
gateways:
- httpbin-gateway
http:
- route:
- destination:
host: httpbin
port:
number: 8000
timeout: 1s
|
我们访问下delay接口，配置一个2s的，会发现有超时错误
重试
首先我们给httpbin的VirtualService的增加一个重试配置
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| kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin
namespace: demo
spec:
hosts:
- "*"
gateways:
- httpbin-gateway
http:
- route:
- destination:
host: httpbin
port:
number: 8000
retry:
attempts: 3
perTryTimeout: 1s
timeout: 8s
EOF
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然后再浏览器中输入http://106.55.219.93/status/500，去httpbin的enovy中查看日志是否有进行重试
从日志中我们看出来重试调用了3次/status/500的接口
熔断
我们先给httpbin来配置下熔断
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| kubectl apply -f - <<EOF
apiVersion: networking.istio.io/v1alpha3
kind: DestinationRule
metadata:
name: httpbin
namespace: demo
spec:
host: httpbin
trafficPolicy:
connectionPool:
tcp:
maxConnections: 1
http:
http1MaxPendingRequests: 1
maxRequestsPerConnection: 1
outlierDetection:
consecutiveErrors: 1
interval: 1s
baseEjectionTime: 3m
maxEjectionPercent: 100
EOF
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具体的测试方法可以参考之前的熔断详细介绍https://www.niewx.cn/istio/2020/12/02/istio%E5%85%A5%E9%97%A8%E7%B3%BB%E5%88%97%E4%B9%8B%E7%86%94%E6%96%AD/
故障注入延迟
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| apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin
namespace: demo
spec:
hosts:
- '*'
gateways:
- httpbin-gateway
http:
- route:
- destination:
host: httpbin
port:
number: 8000
fault:
delay:
fixedDelay: 3000ms
percentage:
value: 100
|
这里我们给httpbin服务注入一个3s的延迟，刷新页面可以发现需要3s才能刷新出页面
故障注入终止
我们给httpbin配置一个终止故障，刷新页面会发现有出现终止报错
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| apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
name: httpbin
namespace: demo
spec:
hosts:
- '*'
gateways:
- httpbin-gateway
http:
- route:
- destination:
host: httpbin
port:
number: 8000
fault:
abort:
httpStatus: 500
percentage:
value: 100
|
