Istio可观测性系列-性能指标

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Istio 指标

Istio 自己的 Metrics

标准指标说明

参考：https://istio.io/latest/docs/reference/config/metrics/

Metrics

对于 HTTP、HTTP/2 和 GRPC 流量，Istio 默认生成以下指标：

  • Request Count (istio_requests_total): This is a COUNTER incremented for every request handled by an Istio proxy.
  • Request Duration (istio_request_duration_milliseconds): This is a DISTRIBUTION which measures the duration of requests.
  • Request Size (istio_request_bytes): This is a DISTRIBUTION which measures HTTP request body sizes.
  • Response Size (istio_response_bytes): This is a DISTRIBUTION which measures HTTP response body sizes.
  • gRPC Request Message Count (istio_request_messages_total): This is a COUNTER incremented for every gRPC message sent from a client.
  • gRPC Response Message Count (istio_response_messages_total): This is a COUNTER incremented for every gRPC message sent from a server.

对于 TCP 流量，Istio 生成以下指标：

  • Tcp Bytes Sent (istio_tcp_sent_bytes_total): This is a COUNTER which measures the size of total bytes sent during response in case of a TCP connection.
  • Tcp Bytes Received (istio_tcp_received_bytes_total): This is a COUNTER which measures the size of total bytes received during request in case of a TCP connection.
  • Tcp Connections Opened (istio_tcp_connections_opened_total): This is a COUNTER incremented for every opened connection.
  • Tcp Connections Closed (istio_tcp_connections_closed_total): This is a COUNTER incremented for every closed connection.

Prometheus 的 Labels

  • Reporter: This identifies the reporter of the request. It is set to destination if report is from a server Istio proxy and source if report is from a client Istio proxy or a gateway.

  • Source Workload: This identifies the name of source workload which controls the source, or “unknown” if the source information is missing.

  • Source Workload Namespace: This identifies the namespace of the source workload, or “unknown” if the source information is missing.

  • Source Principal: This identifies the peer principal of the traffic source. It is set when peer authentication is used.

  • Source App: This identifies the source application based on app label of the source workload, or “unknown” if the source information is missing.

  • Source Version: This identifies the version of the source workload, or “unknown” if the source information is missing.

  • Destination Workload: This identifies the name of destination workload, or “unknown” if the destination information is missing.

  • Destination Workload Namespace: This identifies the namespace of the destination workload, or “unknown” if the destination information is missing.

  • Destination Principal: This identifies the peer principal of the traffic destination. It is set when peer authentication is used.

  • Destination App: This identifies the destination application based on app label of the destination workload, or “unknown” if the destination information is missing.

  • Destination Version: This identifies the version of the destination workload, or “unknown” if the destination information is missing.

  • Destination Service: This identifies destination service host responsible for an incoming request. Ex: details.default.svc.cluster.local.

  • Destination Service Name: This identifies the destination service name. Ex: “details”.

  • Destination Service Namespace: This identifies the namespace of destination service.

  • Request Protocol: This identifies the protocol of the request. It is set to request or connection protocol.

  • Response Code: This identifies the response code of the request. This label is present only on HTTP metrics.

  • Connection Security Policy: This identifies the service authentication policy of the request. It is set to mutual_tls when Istio is used to make communication secure and report is from destination. It is set to unknown when report is from source since security policy cannot be properly populated.

  • Response Flags: Additional details about the response or connection from proxy. In case of Envoy, see %RESPONSE_FLAGS% in Envoy Access Log for more detail.

  • Canonical Service: A workload belongs to exactly one canonical service, whereas it can belong to multiple services. A canonical service has a name and a revision so it results in the following labels.

    source_canonical_service
source_canonical_revision
destination_canonical_service
destination_canonical_revision

  • Destination Cluster: This identifies the cluster of the destination workload. This is set by: global.multiCluster.clusterName at cluster install time.

  • Source Cluster: This identifies the cluster of the source workload. This is set by: global.multiCluster.clusterName at cluster install time.

  • gRPC Response Status: This identifies the response status of the gRPC. This label is present only on gRPC metrics.

使用

istio-proxy 与应用的 Metrics 整合输出

Istio端口与组件

参考：https://istio.io/v1.14/docs/ops/integrations/prometheus/#option-1-metrics-merging

Istio 能够完全通过 prometheus.io annotations 来控制抓取。虽然 prometheus.io annotations 不是 Prometheus 的核心部分，但它们已成为配置抓取的事实标准。

此选项默认启用，但可以通过在 安装 期间传递 --set meshConfig.enablePrometheusMerge=false 来禁用。启用后，将向所有数据平面 pod 添加适当的 prometheus.io annotations 以设置抓取。如果这些注释已经存在，它们将被覆盖。使用此选项，Envoy sidecar 会将 Istio 的指标与应用程序指标合并。合并后的指标将从 /stats/prometheus:15020 中抓取。

此选项以明文形式公开所有指标。

定制：为 Metrics 增加维度

参考： https://istio.io/latest/docs/tasks/observability/metrics/customize-metrics/#custom-statistics-configuration

如，增加端口、与 HTTP HOST 头 维度。

apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  values:
    telemetry:
      v2:
        prometheus:
          configOverride:
            inboundSidecar:
              metrics:
                - name: requests_total
                  dimensions:
                    destination_port: string(destination.port)
                    request_host: request.host
            outboundSidecar:
              metrics:
                - name: requests_total
                  dimensions:
                    destination_port: string(destination.port)
                    request_host: request.host
            gateway:
              metrics:
                - name: requests_total
                  dimensions:
                    destination_port: string(destination.port)
                    request_host: request.host
  1. 使用以下命令将以下 annotation 应用到所有注入的 pod，其中包含要提取到 Prometheus 时间序列 的维度列表：

仅当您的维度不在 [DefaultStatTags 列表] 中时才需要此步骤（https://github.com/istio/istio/blob/release-1.14/pkg/bootstrap/config.go）

apiVersion: apps/v1
kind: Deployment
spec:
  template: # pod template
    metadata:
      annotations:
        sidecar.istio.io/extraStatTags: destination_port,request_host

要在网格范围内启用额外 Tag ，您可以将 extraStatTags 添加到网格配置中：

meshConfig:
  defaultConfig:
    extraStatTags:
     - destination_port
     - request_host

参考 : https://istio.io/latest/docs/reference/config/proxy_extensions/stats/#MetricConfig

定制：加入 request / response 元信息维度

可以把 request 或 repsonse 里一些基础信息 加入到 指标的维度。如，URL Path，这在需要为相同服务分隔统计不同 REST API 的指标时，相当有用。

参考 : https://istio.io/latest/docs/tasks/observability/metrics/classify-metrics/

工作原理

istio stat filter 使用

Istio 在自己的定制版本 Envoy 中，加入了 stats-filter 插件，用于计算 Istio 自己想要的指标：

$ k -n istio-system get envoyfilters.networking.istio.io stats-filter-1.14 -o yaml
apiVersion: networking.istio.io/v1alpha3
kind: EnvoyFilter
metadata:
  annotations:
  labels:
    install.operator.istio.io/owning-resource-namespace: istio-system
    istio.io/rev: default
    operator.istio.io/component: Pilot
    operator.istio.io/version: 1.14.3
  name: stats-filter-1.14
  namespace: istio-system
spec:
  configPatches:
  - applyTo: HTTP_FILTER
    match:
      context: SIDECAR_OUTBOUND
      listener:
        filterChain:
          filter:
            name: envoy.filters.network.http_connection_manager
            subFilter:
              name: envoy.filters.http.router
      proxy:
        proxyVersion: ^1\.14.*
    patch:
      operation: INSERT_BEFORE
      value:
        name: istio.stats
        typed_config:
          '@type': type.googleapis.com/udpa.type.v1.TypedStruct
          type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
          value:
            config:
              configuration:
                '@type': type.googleapis.com/google.protobuf.StringValue
                value: |
                  {
                    "debug": "false",
                    "stat_prefix": "istio"
                  }                  
              root_id: stats_outbound
              vm_config:
                code:
                  local:
                    inline_string: envoy.wasm.stats
                runtime: envoy.wasm.runtime.null
                vm_id: stats_outbound
  - applyTo: HTTP_FILTER
    match:
      context: SIDECAR_INBOUND
      listener:
        filterChain:
          filter:
            name: envoy.filters.network.http_connection_manager
            subFilter:
              name: envoy.filters.http.router
      proxy:
        proxyVersion: ^1\.14.*
    patch:
      operation: INSERT_BEFORE
      value:
        name: istio.stats
        typed_config:
          '@type': type.googleapis.com/udpa.type.v1.TypedStruct
          type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
          value:
            config:
              configuration:
                '@type': type.googleapis.com/google.protobuf.StringValue
                value: |
                  {
                    "debug": "false",
                    "stat_prefix": "istio",
                    "disable_host_header_fallback": true,
                    "metrics": [
                      {
                        "dimensions": {
                          "destination_cluster": "node.metadata['CLUSTER_ID']",
                          "source_cluster": "downstream_peer.cluster_id"
                        }
                      }
                    ]
                  }                  
              root_id: stats_inbound
              vm_config:
                code:
                  local:
                    inline_string: envoy.wasm.stats
                runtime: envoy.wasm.runtime.null
                vm_id: stats_inbound
  - applyTo: HTTP_FILTER
    match:
      context: GATEWAY
      listener:
        filterChain:
          filter:
            name: envoy.filters.network.http_connection_manager
            subFilter:
              name: envoy.filters.http.router
      proxy:
        proxyVersion: ^1\.14.*
    patch:
      operation: INSERT_BEFORE
      value:
        name: istio.stats
        typed_config:
          '@type': type.googleapis.com/udpa.type.v1.TypedStruct
          type_url: type.googleapis.com/envoy.extensions.filters.http.wasm.v3.Wasm
          value:
            config:
              configuration:
                '@type': type.googleapis.com/google.protobuf.StringValue
                value: |
                  {
                    "debug": "false",
                    "stat_prefix": "istio",
                    "disable_host_header_fallback": true
                  }                  
              root_id: stats_outbound
              vm_config:
                code:
                  local:
                    inline_string: envoy.wasm.stats
                runtime: envoy.wasm.runtime.null
                vm_id: stats_outbound
  priority: -1

istio stat Plugin 实现

https://github.com/istio/proxy/blob/release-1.14/extensions/stats/plugin.cc

内置的 Metric:

const std::vector<MetricFactory>& PluginRootContext::defaultMetrics() {
  static const std::vector<MetricFactory> default_metrics = {
      // HTTP, HTTP/2, and GRPC metrics
      MetricFactory{"requests_total", MetricType::Counter,
                    [](::Wasm::Common::RequestInfo&) -> uint64_t { return 1; },
                    static_cast<uint32_t>(Protocol::HTTP) |
                        static_cast<uint32_t>(Protocol::GRPC),
                    count_standard_labels, /* recurrent */ false},
      MetricFactory{"request_duration_milliseconds", MetricType::Histogram,
                    [](::Wasm::Common::RequestInfo& request_info) -> uint64_t {
                      return request_info.duration /* in nanoseconds */ /
                             1000000;
                    },
                    static_cast<uint32_t>(Protocol::HTTP) |
                        static_cast<uint32_t>(Protocol::GRPC),
                    count_standard_labels, /* recurrent */ false},
      MetricFactory{"request_bytes", MetricType::Histogram,
                    [](::Wasm::Common::RequestInfo& request_info) -> uint64_t {
                      return request_info.request_size;
                    },
                    static_cast<uint32_t>(Protocol::HTTP) |
                        static_cast<uint32_t>(Protocol::GRPC),
                    count_standard_labels, /* recurrent */ false},
      MetricFactory{"response_bytes", MetricType::Histogram,
                    [](::Wasm::Common::RequestInfo& request_info) -> uint64_t {
                      return request_info.response_size;
                    },
                    static_cast<uint32_t>(Protocol::HTTP) |
                        static_cast<uint32_t>(Protocol::GRPC),
                    count_standard_labels, /* recurrent */ false},
...

https://github.com/istio/proxy/blob/release-1.14/extensions/stats/plugin.cc#L591

void PluginRootContext::report(::Wasm::Common::RequestInfo& request_info,
                               bool end_stream) {

...
  map(istio_dimensions_, outbound_, peer_node_info.get(), request_info);

  for (size_t i = 0; i < expressions_.size(); i++) {
    if (!evaluateExpression(expressions_[i].token,
                            &istio_dimensions_.at(count_standard_labels + i))) {
      LOG_TRACE(absl::StrCat("Failed to evaluate expression: <",
                             expressions_[i].expression, ">"));
      istio_dimensions_[count_standard_labels + i] = "unknown";
    }
  }

  auto stats_it = metrics_.find(istio_dimensions_);
  if (stats_it != metrics_.end()) {
    for (auto& stat : stats_it->second) {
      if (end_stream || stat.recurrent_) {
        stat.record(request_info);
      }
      LOG_DEBUG(
          absl::StrCat("metricKey cache hit ", ", stat=", stat.metric_id_));
    }
    cache_hits_accumulator_++;
    if (cache_hits_accumulator_ == 100) {
      incrementMetric(cache_hits_, cache_hits_accumulator_);
      cache_hits_accumulator_ = 0;
    }
    return;
  }
...
}

关于 Istio 的指标原理，这是一个很好的参考文章：https://blog.christianposta.com/understanding-istio-telemetry-v2/

Envoy 内置的 Metrics

Istio 默认用 istio-agent 去整合 Envoy 的 metrics。 而 Istio 默认打开的 Envoy 内置 Metrics 很少：

见：https://istio.io/latest/docs/ops/configuration/telemetry/envoy-stats/

cluster_manager
listener_manager
server
cluster.xds-grpc

定制 Envoy 内置的 Metrics

参考：https://istio.io/latest/docs/ops/configuration/telemetry/envoy-stats/

如果要配置 Istio Proxy 以记录 其它 Envoy 原生的指标，您可以将 ProxyConfig.ProxyStatsMatcher 添加到网格配置中。 例如，要全局启用断路器、重试和上游连接的统计信息，您可以指定 stats matcher，如下所示：

代理需要重新启动以获取统计匹配器配置。

apiVersion: install.istio.io/v1alpha1
kind: IstioOperator
spec:
  meshConfig:
    defaultConfig:
      proxyStatsMatcher:
        inclusionRegexps:
          - ".*circuit_breakers.*"
        inclusionPrefixes:
          - "upstream_rq_retry"
          - "upstream_cx"

您还可以使用 proxy.istio.io/config annotation 为个别代码指定配置。 例如，要配置与上面相同的统计信息，您可以将 annotation 添加到 gateway proxy 或 workload，如下所示：

metadata:
  annotations:
    proxy.istio.io/config: |-
      proxyStatsMatcher:
        inclusionRegexps:
        - ".*circuit_breakers.*"
        inclusionPrefixes:
        - "upstream_rq_retry"
        - "upstream_cx"

原理

下面，看看 Istio 默认配置下，如何配置 Envoy。

istioctl proxy-config bootstrap fortio-server | yq eval -P  > envoy-config-bootstrap-default.yaml

输出：

bootstrap:
...
  statsConfig:
    statsTags: # 从指标名中抓取 Tag(prometheus label)
      - tagName: cluster_name
        regex: ^cluster\.((.+?(\..+?\.svc\.cluster\.local)?)\.)
      - tagName: tcp_prefix
        regex: ^tcp\.((.*?)\.)\w+?$
      - tagName: response_code
        regex: (response_code=\.=(.+?);\.;)|_rq(_(\.d{3}))$
      - tagName: response_code_class
        regex: _rq(_(\dxx))$
      - tagName: http_conn_manager_listener_prefix
        regex: ^listener(?=\.).*?\.http\.(((?:[_.[:digit:]]*|[_\[\]aAbBcCdDeEfF[:digit:]]*))\.)
...
    useAllDefaultTags: false
    statsMatcher:
      inclusionList:
        patterns: # 选择要记录的指标
          - prefix: reporter=
          - prefix: cluster_manager
          - prefix: listener_manager
          - prefix: server
          - prefix: cluster.xds-grpc ## 只记录 xDS cluster. 即不记录用户自己服务的 cluster !!!
          - prefix: wasm
          - suffix: rbac.allowed
          - suffix: rbac.denied
          - suffix: shadow_allowed
          - suffix: shadow_denied
          - prefix: component

这时，如果修改 pod 的定义为：

    annotations:
      proxy.istio.io/config: |-
        proxyStatsMatcher:
          inclusionRegexps:
          - "cluster\\..*fortio.*" #proxy upstream(outbound)
          - "cluster\\..*inbound.*" #proxy upstream(inbound，这里一般就是指到同一 pod 中运行的应用了)
          - "http\\..*"
          - "listener\\..*"

产生新的 Envoy 配置：

 "stats_matcher": {
   "inclusion_list": {
     "patterns": [
       {
         "prefix": "reporter="
       },
       {
         "prefix": "cluster_manager"
       },
       {
         "prefix": "listener_manager"
       },
       {
         "prefix": "server"
       },
       {
         "prefix": "cluster.xds-grpc"
       },
 

       {
         "safe_regex": {
           "google_re2": {},
           "regex": "cluster\\..*fortio.*"
         }
       },
       {
         "safe_regex": {
           "google_re2": {},
           "regex": "cluster\\..*inbound.*"
         }
       },
       {
         "safe_regex": {
           "google_re2": {},
           "regex": "http\\..*"
         }
       },
       {
         "safe_regex": {
           "google_re2": {},
           "regex": "listener\\..*"
         }
       },

总结：Istio-Proxy 指标地图

要做好监控，首先要深入了解指标原理。而要了解指标原理，当然要知道指标是产生流程中的什么位置，什么组件。看完上面关于 Envoy 与 Istio 的指标说明后。可以大概得到以下结论：

Istio-Proxy 指标地图

本节的实验环境说明见于： {ref}`appendix-lab-env/appendix-lab-env-base:简单分层实验环境`

本文出自https://istio-insider.readthedocs.io/