Shulou(Shulou.com)06/02 Report--

The file Pilot is generated by the Pilot-agent process based on the service startup parameters and the information of Kubernetes Server API. The configuration file framework is shown in figure 3:

The information contained in Node is shown in figure 4:

The cluster attribute is emphasized here. The value of this attribute is productpage, which indicates that the current istio-proxy service is the proxy service of the productpage application. After the request for calling productpage service is intercepted, iptables forwards it directly to the istio-proxy for processing.

The information contained in stats_config is shown in figure 5:

Static_config focuses on setting the naming rules for some attributes.

The information contained in admin is shown in figure 6:

Admin is similar to a manager inside Envoy, exposing port 15000 can only be accessed inside the container.

Additional interface information can be obtained through curl http://127.0.0.1:15000/help access, as shown in figure 7 below:

The information contained in dynamic_resources is shown in figure 8:

The ADS aggregation discovery service is used to record pilot call XDS interface in dynamic_resources, which can better ensure the consistency of the data obtained from pilot.

Some of the information contained in static_resources is shown in figure 9:

The value of the static_resources name attribute is xds-grpc, which is consistent with the value of cluster_name in the information of the above dynamic_resources module. At the same time, the xds-grpc object information includes the service address "istio-pilot.istio-system:15010" of the pilot component, that is, the service address for istio-proxy to obtain dynamic information from pilot. Istio-proxy (Envoy) calls the XDS interface through this address to obtain service information. In addition, the address of the zipkin service is provided in static_resources, and zipkin is used for distributed tracking of the service.

To sum up, when Envoy starts, the pilot-agent process generates the configuration file needed for Envoy startup. Envoy dynamically obtains the service information based on the pilot address information carried in the configuration file, and dynamically obtains the listener,cluster,endpoint and route information of the service based on the XDS interface provided by pilot.

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