本指南演示了如何为作为 OSM 托管服务网格的一部分目标配置断路。

先决条件

  • Kubernetes 集群运行版本 v1.20.0 或者更高。
  • 已安装 OSM。
  • 使用 kubectl 与 API server 交互。
  • 已安装 osm 命令行工具，用于管理服务网格。
  • OSM 版本高于 v1.1.0

演示

下面的演示展示了一个负载测试客户端 fortio 向 httpbin service 发送流量。 我们将看到当配置的熔断限制触发时，为 httpbin service 配置的流量应用熔断器是如何影响 fortio 客户端。

  1. 为简单起见，启用 permissive traffic policy mode 以便网格内的应用程序连接，而不需要显式配置 SMI 流量访问策略。

    export osm_namespace=osm-system # Replace osm-system with the namespace where OSM is installed
kubectl patch meshconfig osm-mesh-config -n "$osm_namespace" -p '{"spec":{"traffic":{"enablePermissiveTrafficPolicyMode":true}}}'  --type=merge

  2. 在 httpbin 命名空间下部署 httpbin 客户端，并将命名空间纳入网格管理。httpbin service 运行在 14001 端口上。

    # Create the httpbin namespace
kubectl create namespace httpbin
   
# Add the namespace to the mesh
osm namespace add httpbin
   
# Deploy httpbin service in the httpbin namespace
kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.1/manifests/samples/httpbin/httpbin.yaml -n httpbin

    确认 httpbin service 和 pod 启动并运行。

    $ kubectl get svc -n httpbin
NAME      TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)     AGE
httpbin   ClusterIP   10.96.198.23   <none>        14001/TCP   20s

    $ kubectl get pods -n httpbin
NAME                     READY   STATUS    RESTARTS   AGE
httpbin-5b8b94b9-lt2vs   2/2     Running   0          20s

  3. 在 client 命名空间下部署 fortio 客户端，并将命名空间纳入网格管理。

    # Create the client namespace
kubectl create namespace client
   
# Add the namespace to the mesh
osm namespace add client
   
# Deploy fortio client in the client namespace
kubectl apply -f https://raw.githubusercontent.com/openservicemesh/osm-docs/release-v1.1/manifests/samples/fortio/fortio.yaml -n client

    确认 fortio 客户端 pod 启动并运行。

    $ kubectl get pods -n client
NAME                      READY   STATUS    RESTARTS   AGE
fortio-6477f8495f-bj4s9   2/2     Running   0          19s

  4. 确认 fortio 客户端可以成功发送 HTTP 请求到 httpbin service 的 14001 端口。我们将使用 3 个并发连接 (-c 3) 调用httpbin service 并发送 50 个请求(-n 50)。

    $ export fortio_pod="$(kubectl get pod -n client -l app=fortio -o jsonpath='{.items[0].metadata.name}')"
   
$ kubectl exec "$fortio_pod" -c fortio -n client -- /usr/bin/fortio load -c 3 -qps 0 -n 50 -loglevel Warning http://httpbin.httpbin.svc.cluster.local:14001/get
17:48:46 I logger.go:127> Log level is now 3 Warning (was 2 Info)
Fortio 1.17.1 running at 0 queries per second, 8->8 procs, for 50 calls: http://httpbin.httpbin.svc.cluster.local:14001/get
Starting at max qps with 3 thread(s) [gomax 8] for exactly 50 calls (16 per thread + 2)
Ended after 438.1586ms : 50 calls. qps=114.11
Aggregated Function Time : count 50 avg 0.026068422 +/- 0.05104 min 0.0029766 max 0.1927961 sum 1.3034211
# range, mid point, percentile, count
>= 0.0029766 <= 0.003 , 0.0029883 , 2.00, 1
> 0.003 <= 0.004 , 0.0035 , 30.00, 14
> 0.004 <= 0.005 , 0.0045 , 32.00, 1
> 0.005 <= 0.006 , 0.0055 , 44.00, 6
> 0.006 <= 0.007 , 0.0065 , 46.00, 1
> 0.007 <= 0.008 , 0.0075 , 66.00, 10
> 0.008 <= 0.009 , 0.0085 , 72.00, 3
> 0.009 <= 0.01 , 0.0095 , 74.00, 1
> 0.01 <= 0.011 , 0.0105 , 82.00, 4
> 0.03 <= 0.035 , 0.0325 , 86.00, 2
> 0.035 <= 0.04 , 0.0375 , 88.00, 1
> 0.12 <= 0.14 , 0.13 , 94.00, 3
> 0.18 <= 0.192796 , 0.186398 , 100.00, 3
# target 50% 0.0072
# target 75% 0.010125
# target 90% 0.126667
# target 99% 0.190663
# target 99.9% 0.192583
Sockets used: 3 (for perfect keepalive, would be 3)
Jitter: false
Code 200 : 50 (100.0 %)
Response Header Sizes : count 50 avg 230.3 +/- 0.6708 min 230 max 232 sum 11515
Response Body/Total Sizes : count 50 avg 582.3 +/- 0.6708 min 582 max 584 sum 29115
All done 50 calls (plus 0 warmup) 26.068 ms avg, 114.1 qps

    如上所示，所有的请求成功。

    Code 200 : 50 (100.0 %)

  5. 接下来，使用 UpstreamTrafficSetting 资源为请求到 httpbin service 的流量应用配置熔断器，并将最大并发连接数和请求数限制为 1

    注意： UpstreamTrafficSetting 资源必须创建在与上游（目标）service 相同的命名空间中，并且主机必须设置为 Kubernetes service 的 FQDN。

    kubectl apply -f - <<EOF
apiVersion: policy.openservicemesh.io/v1alpha1
kind: UpstreamTrafficSetting
metadata:
  name: httpbin
  namespace: httpbin
spec:
  host: httpbin.httpbin.svc.cluster.local
  connectionSettings:
    tcp:
      maxConnections: 1
    http:
      maxPendingRequests: 1
      maxRequestsPerConnection: 1
EOF

  6. 确认由于上面配置的连接和请求级别熔断限制，fortio 客户端无法发出与以前相同数量的成功请求。

    $ kubectl exec "$fortio_pod" -c fortio -n client -- /usr/bin/fortio load -c 3 -qps 0 -n 50 -loglevel Warning http://httpbin.httpbin.svc.cluster.local:14001/get
17:59:19 I logger.go:127> Log level is now 3 Warning (was 2 Info)
Fortio 1.17.1 running at 0 queries per second, 8->8 procs, for 50 calls: http://httpbin.httpbin.svc.cluster.local:14001/get
Starting at max qps with 3 thread(s) [gomax 8] for exactly 50 calls (16 per thread + 2)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [2] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [2] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [2] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [0] Non ok http code 503 (HTTP/1.1 503)
17:59:19 W http_client.go:806> [1] Non ok http code 503 (HTTP/1.1 503)
Ended after 122.6576ms : 50 calls. qps=407.64
Aggregated Function Time : count 50 avg 0.006086436 +/- 0.00731 min 0.0005739 max 0.042604 sum 0.3043218
# range, mid point, percentile, count
>= 0.0005739 <= 0.001 , 0.00078695 , 14.00, 7
> 0.001 <= 0.002 , 0.0015 , 32.00, 9
> 0.002 <= 0.003 , 0.0025 , 40.00, 4
> 0.003 <= 0.004 , 0.0035 , 52.00, 6
> 0.004 <= 0.005 , 0.0045 , 64.00, 6
> 0.005 <= 0.006 , 0.0055 , 66.00, 1
> 0.006 <= 0.007 , 0.0065 , 72.00, 3
> 0.007 <= 0.008 , 0.0075 , 74.00, 1
> 0.008 <= 0.009 , 0.0085 , 76.00, 1
> 0.009 <= 0.01 , 0.0095 , 80.00, 2
> 0.01 <= 0.011 , 0.0105 , 82.00, 1
> 0.011 <= 0.012 , 0.0115 , 88.00, 3
> 0.012 <= 0.014 , 0.013 , 92.00, 2
> 0.014 <= 0.016 , 0.015 , 96.00, 2
> 0.025 <= 0.03 , 0.0275 , 98.00, 1
> 0.04 <= 0.042604 , 0.041302 , 100.00, 1
# target 50% 0.00383333
# target 75% 0.0085
# target 90% 0.013
# target 99% 0.041302
# target 99.9% 0.0424738
Sockets used: 31 (for perfect keepalive, would be 3)
Jitter: false
Code 200 : 21 (42.0 %)
Code 503 : 29 (58.0 %)
Response Header Sizes : count 50 avg 96.68 +/- 113.6 min 0 max 231 sum 4834
Response Body/Total Sizes : count 50 avg 399.42 +/- 186.2 min 241 max 619 sum 19971
All done 50 calls (plus 0 warmup) 6.086 ms avg, 407.6 qps

    如上所示，只有 42% 的请求成功，其余的请求在熔断器打开时失败

    Code 200 : 21 (42.0 %)
Code 503 : 29 (58.0 %)

  7. 检查 Envoy sidecar 统计信息以查看与触发断路器的请求有关的统计信息

    $ osm proxy get stats "$fortio_pod" -n client | grep 'httpbin.*pending'
cluster.httpbin/httpbin|14001.circuit_breakers.default.remaining_pending: 1
cluster.httpbin/httpbin|14001.circuit_breakers.default.rq_pending_open: 0
cluster.httpbin/httpbin|14001.circuit_breakers.high.rq_pending_open: 0
cluster.httpbin/httpbin|14001.upstream_rq_pending_active: 0
cluster.httpbin/httpbin|14001.upstream_rq_pending_failure_eject: 0
cluster.httpbin/httpbin|14001.upstream_rq_pending_overflow: 29
cluster.httpbin/httpbin|14001.upstream_rq_pending_total: 25

    cluster.httpbin/httpbin|14001.upstream_rq_pending_overflow: 29 表示有 29 个请求触发了熔断器，这与上一步中看到的失败请求数相匹配：Code 503 : 29 (58.0 %)