Container metrics

[feiskyer]

Kubelet is adding container metrics (CPU, memory and filesystem usage) in CRI (https://github.com/kubernetes/kubernetes/blob/master/pkg/kubelet/apis/cri/v1alpha1/runtime/api.proto#L1019-L1093), we should consider if and how to support this.

// ContainerAttributes provides basic information of the container.
message ContainerAttributes {
    // ID of the container.
    string id = 1;
    // Metadata of the container.
    ContainerMetadata metadata = 2;
    // Key-value pairs that may be used to scope and select individual resources.
    map<string,string> labels = 3;
    // Unstructured key-value map holding arbitrary metadata.
    // Annotations MUST NOT be altered by the runtime; the value of this field
    // MUST be identical to that of the corresponding ContainerConfig used to
    // instantiate the Container this status represents.
    map<string,string> annotations = 4;
}

// ContainerStats provides the resource usage statistics for a container.
message ContainerStats {
    // Information of the container.
    ContainerAttributes attributes = 1;
    // CPU usage gathered from the container.
    CpuUsage cpu = 2;
    // Memory usage gathered from the container.
    MemoryUsage memory = 3;
    // Usage of the writeable layer.
    FilesystemUsage writable_layer = 4;
}

// CpuUsage provides the CPU usage information.
message CpuUsage {
    // Timestamp in nanoseconds at which the information were collected. Must be > 0.
    int64 timestamp = 1;
    // Cumulative CPU usage (sum across all cores) since object creation.
    UInt64Value usage_core_nano_seconds = 2;
}

// MemoryUsage provides the memory usage information.
message MemoryUsage {
    // Timestamp in nanoseconds at which the information were collected. Must be > 0.
    int64 timestamp = 1;
    // The amount of working set memory in bytes.
    UInt64Value working_set_bytes = 2;
}