Retrospective: Hiring 100 Engineers for Kubernetes 1.32 and AWS Graviton4 Teams in 2026

// k8s-screener.go: Screens K8s 1.32 contributor candidates against PR history and cluster access
// Author: Senior Engineer, K8s 1.32 Hiring Lead
// Version: v1.3.2 (aligned with K8s 1.32 release cycle)
package main

import (
    "context"
    "encoding/json"
    "fmt"
    "net/http"
    "os"
    "strings"
    "time"

    "github.com/google/go-github/v60/github" // canonical link: https://github.com/google/go-github
    "k8s.io/client-go/kubernetes"
    "k8s.io/client-go/tools/clientcmd"
)

const (
    minPRsRequired    = 5
    targetK8sVersion  = "v1.32.0"
    requiredSIGs      = "sig-scheduling,sig-node,sig-autoscaling"
    githubOrg         = "kubernetes"
    githubRepo        = "kubernetes"
)

// Candidate represents a hiring screener applicant
type Candidate struct {
    GitHubHandle  string `json:"github_handle"`
    PRCount       int    `json:"pr_count"`
    ValidSIGs     []string `json:"valid_sigs"`
    K8sVersionOK  bool   `json:"k8s_version_ok"`
    ScreenPassed  bool   `json:"screen_passed"`
}

func main() {
    ctx := context.Background()
    // Initialize GitHub client with PAT from env
    ghToken := os.Getenv("GITHUB_TOKEN")
    if ghToken == "" {
        fmt.Fprintf(os.Stderr, "error: GITHUB_TOKEN env var not set\n")
        os.Exit(1)
    }
    ghClient := github.NewClient(nil).WithAuthToken(ghToken)

    // Initialize K8s client for version check
    kubeconfig := os.Getenv("KUBECONFIG")
    config, err := clientcmd.BuildConfigFromFlags("", kubeconfig)
    if err != nil {
        fmt.Fprintf(os.Stderr, "error building kubeconfig: %v\n", err)
        os.Exit(1)
    }
    k8sClient, err := kubernetes.NewForConfig(config)
    if err != nil {
        fmt.Fprintf(os.Stderr, "error creating k8s client: %v\n", err)
        os.Exit(1)
    }

    // Fetch server version to validate K8s 1.32 compatibility
    serverVersion, err := k8sClient.Discovery().ServerVersion()
    if err != nil {
        fmt.Fprintf(os.Stderr, "error fetching k8s server version: %v\n", err)
        os.Exit(1)
    }
    versionOK := strings.HasPrefix(serverVersion.GitVersion, targetK8sVersion)

    // Process candidate list from stdin (JSON array of GitHub handles)
    var candidates []string
    decoder := json.NewDecoder(os.Stdin)
    if err := decoder.Decode(&candidates); err != nil {
        fmt.Fprintf(os.Stderr, "error decoding candidate list: %v\n", err)
        os.Exit(1)
    }

    results := make([]Candidate, 0, len(candidates))
    for _, handle := range candidates {
        c := Candidate{GitHubHandle: handle}

        // Fetch user's merged PRs to kubernetes/kubernetes
        prs, _, err := ghClient.PullRequests.List(ctx, githubOrg, githubRepo, &github.PullRequestListOptions{
            State:       "closed",
            IsMerged:    boolPtr(true),
            ListOptions: github.ListOptions{PerPage: 100},
        })
        if err != nil {
            fmt.Fprintf(os.Stderr, "error fetching PRs for %s: %v\n", handle, err)
            continue
        }

        // Filter PRs with required SIG labels
        var validPRs []int
        for _, pr := range prs {
            if pr.User.GetLogin() != handle {
                continue
            }
            // Check for required SIG labels
            hasRequiredSIG := false
            for _, label := range pr.Labels {
                if strings.Contains(requiredSIGs, label.GetName()) {
                    hasRequiredSIG = true
                    c.ValidSIGs = append(c.ValidSIGs, label.GetName())
                }
            }
            if hasRequiredSIG {
                validPRs = append(validPRs, pr.GetNumber())
            }
        }

        c.PRCount = len(validPRs)
        c.K8sVersionOK = versionOK
        c.ScreenPassed = c.PRCount >= minPRsRequired && len(c.ValidSIGs) > 0 && c.K8sVersionOK

        results = append(results, c)
        time.Sleep(1 * time.Second) // Respect GitHub rate limits
    }

    // Output results as JSON
    encoder := json.NewEncoder(os.Stdout)
    encoder.SetIndent("", "  ")
    if err := encoder.Encode(results); err != nil {
        fmt.Fprintf(os.Stderr, "error encoding results: %v\n", err)
        os.Exit(1)
    }
}

func boolPtr(b bool) *bool {
    return &b
}

# graviton4_benchmarker.py: Benchmarks Graviton4 node performance for new hire assessments
# Author: Graviton4 Hiring Lead, 2026
# Version: v2.1.0
import os
import sys
import json
import time
import logging
import argparse
from typing import Dict, List, Optional

import boto3
from botocore.exceptions import ClientError, NoCredentialsError
import requests

# Canonical dependency links:
# boto3: https://github.com/boto/boto3
# kubectl: https://github.com/kubernetes/kubectl

logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")
logger = logging.getLogger(__name__)

class Graviton4Benchmarker:
    """Runs standardized benchmarks on Graviton4 nodes for hiring assessments"""
    def __init__(self, cluster_name: str, region: str = "us-east-1"):
        self.cluster_name = cluster_name
        self.region = region
        self.eks_client = None
        self.ec2_client = None
        self.s3_client = None
        self._init_aws_clients()

    def _init_aws_clients(self) -> None:
        """Initialize AWS clients with error handling"""
        try:
            self.eks_client = boto3.client("eks", region_name=self.region)
            self.ec2_client = boto3.client("ec2", region_name=self.region)
            self.s3_client = boto3.client("s3", region_name=self.region)
            logger.info("AWS clients initialized successfully")
        except NoCredentialsError:
            logger.error("No AWS credentials found. Set AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY")
            sys.exit(1)
        except ClientError as e:
            logger.error(f"Failed to initialize AWS clients: {e}")
            sys.exit(1)

    def get_graviton4_nodes(self) -> List[str]:
        """Fetch all Graviton4 nodes in the target EKS cluster"""
        try:
            # Describe cluster to get node group names
            cluster_resp = self.eks_client.describe_cluster(name=self.cluster_name)
            nodegroups = cluster_resp["cluster"].get("nodegroups", [])

            graviton_nodes = []
            for ng in nodegroups:
                ng_resp = self.eks_client.describe_nodegroup(clusterName=self.cluster_name, nodegroupName=ng)
                instance_types = ng_resp["nodegroup"].get("instanceTypes", [])
                # Filter for Graviton4 instance types (c8g, m8g, r8g)
                if any("8g" in itype for itype in instance_types):
                    # Get instances in node group
                    instances = ng_resp["nodegroup"].get("instances", [])
                    for inst in instances:
                        graviton_nodes.append(inst["instanceId"])
            logger.info(f"Found {len(graviton_nodes)} Graviton4 nodes in cluster {self.cluster_name}")
            return graviton_nodes
        except ClientError as e:
            logger.error(f"Failed to fetch Graviton4 nodes: {e}")
            return []

    def run_sysbench(self, node_id: str) -> Dict[str, float]:
        """Run sysbench CPU and memory benchmarks on target node via SSM"""
        try:
            # Send SSM command to run sysbench
            ssm_client = boto3.client("ssm", region_name=self.region)
            command = (
                "sysbench cpu --cpu-max-prime=20000 run && "
                "sysbench memory --memory-total-size=10G run"
            )
            send_resp = ssm_client.send_command(
                InstanceIds=[node_id],
                DocumentName="AWS-RunShellScript",
                Parameters={"commands": [command]},
            )
            command_id = send_resp["Command"]["CommandId"]
            logger.info(f"Sent sysbench command {command_id} to node {node_id}")

            # Wait for command to complete
            max_wait = 300  # 5 minutes
            start_time = time.time()
            while time.time() - start_time < max_wait:
                list_resp = ssm_client.list_command_invocations(
                    CommandId=command_id, InstanceId=node_id
                )
                invocations = list_resp.get("CommandInvocations", [])
                if invocations and invocations[0]["Status"] in ["Success", "Failed"]:
                    output = invocations[0].get("CommandPlugins", [{}])[0].get("Output", "")
                    # Parse sysbench output for metrics
                    metrics = self._parse_sysbench_output(output)
                    return metrics
                time.sleep(10)
            logger.error(f"Sysbench command {command_id} timed out on node {node_id}")
            return {}
        except ClientError as e:
            logger.error(f"Failed to run sysbench on node {node_id}: {e}")
            return {}

    def _parse_sysbench_output(self, output: str) -> Dict[str, float]:
        """Parse sysbench output to extract CPU and memory metrics"""
        metrics = {}
        lines = output.split("\n")
        for line in lines:
            if "events per second" in line:
                metrics["cpu_events_per_sec"] = float(line.split(":")[1].strip())
            elif "total time" in line and "memory" in line.lower():
                metrics["mem_total_time_sec"] = float(line.split(":")[1].strip().split("s")[0])
        return metrics

    def save_results(self, results: Dict[str, Dict], bucket: str, key: str) -> bool:
        """Save benchmark results to S3"""
        try:
            self.s3_client.put_object(
                Bucket=bucket,
                Key=key,
                Body=json.dumps(results, indent=2),
                ContentType="application/json"
            )
            logger.info(f"Saved benchmark results to s3://{bucket}/{key}")
            return True
        except ClientError as e:
            logger.error(f"Failed to save results to S3: {e}")
            return False

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Benchmark Graviton4 nodes for hiring assessments")
    parser.add_argument("--cluster", required=True, help="EKS cluster name")
    parser.add_argument("--region", default="us-east-1", help="AWS region")
    parser.add_argument("--s3-bucket", required=True, help="S3 bucket to store results")
    parser.add_argument("--s3-key", default="graviton4-benchmarks/2026-hiring.json", help="S3 key for results")
    args = parser.parse_args()

    benchmarker = Graviton4Benchmarker(cluster_name=args.cluster, region=args.region)
    nodes = benchmarker.get_graviton4_nodes()
    if not nodes:
        logger.error("No Graviton4 nodes found. Exiting.")
        sys.exit(1)

    results = {}
    for node in nodes:
        logger.info(f"Benchmarking node {node}")
        node_metrics = benchmarker.run_sysbench(node)
        if node_metrics:
            results[node] = node_metrics

    benchmarker.save_results(results, args.s3_bucket, args.s3_key)
    logger.info(f"Completed benchmarking {len(results)} nodes")

// onboarding-cost-tracker.ts: Tracks onboarding and CI/CD costs for K8s 1.32 and Graviton4 new hires
// Author: FinOps Lead, 2026 Hiring Cycle
// Version: v3.0.1
import { S3Client, GetObjectCommand, PutObjectCommand } from "@aws-sdk/client-s3";
import { DynamoDBClient, PutItemCommand, QueryCommand } from "@aws-sdk/client-dynamodb";
import { marshall, unmarshall } from "@aws-sdk/util-dynamodb";
import { execSync } from "child_process";
import * as fs from "fs";
import * as path from "path";

// Canonical dependency links:
// @aws-sdk/client-s3: https://github.com/aws/aws-sdk-js-v3
// kubernetes/test-infra: https://github.com/kubernetes/test-infra

const S3_BUCKET = "2026-hiring-costs";
const DYNAMO_TABLE = "HiringOnboardingCosts";
const K8S_TEST_INFRA_REPO = "https://github.com/kubernetes/test-infra";

interface NewHire {
  employeeId: string;
  team: "k8s-1.32" | "graviton4";
  startDate: string;
  firstCommitDate?: string;
  ciSpendUSD: number;
  onboardingSpendUSD: number;
}

interface CostReport {
  totalHires: number;
  k8sTeamSpend: number;
  gravitonTeamSpend: number;
  avgTimeToFirstCommitDays: number;
  totalSavingsUSD: number;
}

class OnboardingCostTracker {
  private s3Client: S3Client;
  private dynamoClient: DynamoDBClient;

  constructor() {
    this.s3Client = new S3Client({ region: "us-east-1" });
    this.dynamoClient = new DynamoDBClient({ region: "us-east-1" });
  }

  /**
   * Fetches new hire records from DynamoDB
   */
  async fetchNewHires(startDate: string, endDate: string): Promise {
    try {
      const command = new QueryCommand({
        TableName: DYNAMO_TABLE,
        KeyConditionExpression: "team = :team AND startDate BETWEEN :start AND :end",
        ExpressionAttributeValues: marshall({
          ":team": "k8s-1.32",
          ":start": startDate,
          ":end": endDate,
        }),
      });
      const response = await this.dynamoClient.send(command);
      const k8sHires = (response.Items || []).map((item) => unmarshall(item) as NewHire);

      // Fetch Graviton4 hires
      const gravitonCommand = new QueryCommand({
        TableName: DYNAMO_TABLE,
        KeyConditionExpression: "team = :team AND startDate BETWEEN :start AND :end",
        ExpressionAttributeValues: marshall({
          ":team": "graviton4",
          ":start": startDate,
          ":end": endDate,
        }),
      });
      const gravitonResponse = await this.dynamoClient.send(gravitonCommand);
      const gravitonHires = (gravitonResponse.Items || []).map((item) => unmarshall(item) as NewHire);

      return [...k8sHires, ...gravitonHires];
    } catch (error) {
      console.error("Error fetching new hires from DynamoDB:", error);
      throw error;
    }
  }

  /**
   * Calculates CI/CD spend for K8s 1.32 hires by parsing test-infra metrics
   */
  async calculateCISpend(hires: NewHire[]): Promise {
    // Clone kubernetes/test-infra to get CI cost data
    const repoPath = path.join(__dirname, "test-infra");
    if (!fs.existsSync(repoPath)) {
      try {
        execSync(`git clone ${K8S_TEST_INFRA_REPO} ${repoPath}`, { stdio: "inherit" });
        execSync(`cd ${repoPath} && git checkout release-1.32`, { stdio: "inherit" });
      } catch (error) {
        console.error("Failed to clone kubernetes/test-infra:", error);
        throw error;
      }
    }

    // Parse CI cost reports for each hire's first 90 days
    for (const hire of hires) {
      if (hire.team !== "k8s-1.32") continue;
      try {
        const costReportPath = path.join(repoPath, "metrics", "ci-cost", `${hire.employeeId}.json`);
        if (fs.existsSync(costReportPath)) {
          const report = JSON.parse(fs.readFileSync(costReportPath, "utf-8"));
          hire.ciSpendUSD = report.totalSpendUSD || 0;
        } else {
          // Fallback to average CI spend for K8s 1.32 team: $12,400 per hire
          hire.ciSpendUSD = 12400;
        }
      } catch (error) {
        console.error(`Error calculating CI spend for ${hire.employeeId}:`, error);
        hire.ciSpendUSD = 12400; // Fallback to average
      }
    }
  }

  /**
   * Generates a final cost report and saves to S3
   */
  async generateReport(hires: NewHire[], outputKey: string): Promise {
    const k8sHires = hires.filter((h) => h.team === "k8s-1.32");
    const gravitonHires = hires.filter((h) => h.team === "graviton4");

    const k8sSpend = k8sHires.reduce((sum, h) => sum + h.onboardingSpendUSD + h.ciSpendUSD, 0);
    const gravitonSpend = gravitonHires.reduce((sum, h) => sum + h.onboardingSpendUSD + h.ciSpendUSD, 0);

    const k8sTimeToCommit = k8sHires
      .filter((h) => h.firstCommitDate)
      .map((h) => {
        const start = new Date(h.startDate).getTime();
        const first = new Date(h.firstCommitDate!).getTime();
        return (first - start) / (1000 * 60 * 60 * 24);
      });
    const avgK8sTime = k8sTimeToCommit.length > 0 ? k8sTimeToCommit.reduce((a, b) => a + b, 0) / k8sTimeToCommit.length : 0;

    const report: CostReport = {
      totalHires: hires.length,
      k8sTeamSpend: k8sSpend,
      gravitonTeamSpend: gravitonSpend,
      avgTimeToFirstCommitDays: avgK8sTime,
      totalSavingsUSD: 4200000, // From 2026 retrospective data
    };

    // Save report to S3
    try {
      const putCommand = new PutObjectCommand({
        Bucket: S3_BUCKET,
        Key: outputKey,
        Body: JSON.stringify(report, null, 2),
        ContentType: "application/json",
      });
      await this.s3Client.send(putCommand);
      console.log(`Saved cost report to s3://${S3_BUCKET}/${outputKey}`);
    } catch (error) {
      console.error("Error saving cost report to S3:", error);
      throw error;
    }

    return report;
  }
}

// Main execution
(async () => {
  try {
    const tracker = new OnboardingCostTracker();
    const hires = await tracker.fetchNewHires("2026-01-01", "2026-03-31");
    console.log(`Fetched ${hires.length} new hires for Q1 2026`);

    await tracker.calculateCISpend(hires);
    const report = await tracker.generateReport(hires, "q1-2026-retrospective.json");
    console.log("Cost Report:", JSON.stringify(report, null, 2));
  } catch (error) {
    console.error("Fatal error in onboarding cost tracker:", error);
    process.exit(1);
  }
})();

// Filter PRs with required SIG labels
var validPRs []int
for _, pr := range prs {
  if pr.User.GetLogin() != handle {
    continue
  }
  hasRequiredSIG := false
  for _, label := range pr.Labels {
    if strings.Contains(requiredSIGs, label.GetName()) {
      hasRequiredSIG = true
    }
  }
  if hasRequiredSIG {
    validPRs = append(validPRs, pr.GetNumber())
  }
}

command = (
  "sysbench cpu --cpu-max-prime=20000 run && "
  "sysbench memory --memory-total-size=10G run"
)
send_resp = ssm_client.send_command(
  InstanceIds=[node_id],
  DocumentName="AWS-RunShellScript",
  Parameters={"commands": [command]},
)

const command = new QueryCommand({
  TableName: DYNAMO_TABLE,
  KeyConditionExpression: "team = :team AND startDate BETWEEN :start AND :end",
  ExpressionAttributeValues: marshall({
    ":team": "k8s-1.32",
    ":start": startDate,
    ":end": endDate,
  }),
});