added kubelet.rs

Author: razvan

Cargo.lock

@@ -25,6 +25,7 @@ educe =  { version = "0.6.0", default-features = false, features = ["Clone", "De
 either = "1.13.0"
 futures = "0.3.30"
 futures-util = "0.3.30"
+http = "1.3.1"
 indexmap = "2.5.0"
 indoc = "2.0.6"
 insta = { version= "1.40", features = ["glob"] }

Cargo.toml

@@ -28,6 +28,7 @@ dockerfile-parser.workspace = true
 either.workspace = true
 educe.workspace = true
 futures.workspace = true
+http.workspace = true
 indexmap.workspace = true
 json-patch.workspace = true
 k8s-openapi.workspace = true

crates/stackable-operator/Cargo.toml

@@ -0,0 +1,75 @@
+use k8s_openapi::api::core::v1::Node;
+use kube::{
+    Api,
+    api::{ListParams, ResourceExt},
+    client::Client,
+};
+use serde::Deserialize;
+use http;
+use snafu::{Snafu, ResultExt, OptionExt};
+
+#[derive(Debug, Snafu)]
+pub enum Error {
+
+    #[snafu(display("failed to list nodes"))]
+    ListNodes {
+        source: kube::Error,
+    },
+    #[snafu(display("failed to build proxy/configz request"))]
+    ConfigzRequest {
+        source: http::Error,
+    },
+
+    #[snafu(display("failed to fetch kubelet config from node {node}"))]
+    FetchNodeKubeletConfig {
+        source: kube::Error,
+        node: String,
+    },
+
+    #[snafu(display("failed to fetch `kubeletconfig` JSON key from configz response"))]
+    KubeletConfigJsonKey,
+
+    #[snafu(display("failed to deserialize kubelet config JSON"))]
+    KubeletConfigJson {
+        source: serde_json::Error,
+    },
+
+    #[snafu(display("empty Kubernetes nodes list"))]
+    EmptyKubernetesNodesList,
+}
+
+#[derive(Debug, Deserialize)]
+#[serde(rename_all = "camelCase")]
+struct KubeletConfig {
+    cluster_domain: String,
+}
+
+impl KubeletConfig {
+    pub async fn fetch(client: &Client) -> Result<Self, Error> {
+        let api: Api<Node> = Api::all(client.clone());
+        let nodes = api.list(&ListParams::default()).await.context(ListNodesSnafu)?;
+        let node = nodes.iter().next().context(EmptyKubernetesNodesListSnafu)?;
+
+        let name = node.name_any();
+
+        // Query node stats by issuing a request to the admin endpoint.
+        // See https://kubernetes.io/docs/reference/instrumentation/node-metrics/
+        let url = format!("/api/v1/nodes/{}/proxy/configz", name);
+        let req = http::Request::get(url).body(Default::default()).context(ConfigzRequestSnafu)?;
+
+        // Deserialize JSON response as a JSON value. Alternatively, a type that
+        // implements `Deserialize` can be used.
+        let resp = client.request::<serde_json::Value>(req).await.context(FetchNodeKubeletConfigSnafu { node: name })?;
+
+        // Our JSON value is an object so we can treat it like a dictionary.
+        let summary = resp
+            .get("kubeletconfig")
+            .context(KubeletConfigJsonKeySnafu)?;
+
+        // The base JSON representation includes a lot of metrics, including
+        // container metrics. Use a `NodeMetrics` type to deserialize only the
+        // values we care about.
+        serde_json::from_value::<KubeletConfig>(summary.to_owned()).context(KubeletConfigJsonSnafu)
+    }
+
+}

crates/stackable-operator/src/utils/kubelet.rs

@@ -1,6 +1,7 @@
 pub mod bash;
 pub mod cluster_info;
 pub mod crds;
+mod kubelet;
 pub mod logging;
 mod option;
 mod url;