Use HTTP/1.1 to perform readiness check

core/src/main/java/io/javaoperatorsdk/jenvtest/process/KubeAPIServerProcess.java

@@ -89,9 +89,7 @@ public void waitUntilReady() {
     var readinessChecker = new ProcessReadinessChecker();
     var timeout = config.getStartupTimeout();
     var startTime = System.currentTimeMillis();
-    // the 1.29.0 binary has issue with this. Will temporarily comment out and further investigate.
-    // But with this now all the executions are failing
-    // readinessChecker.waitUntilReady(apiServerPort, "readyz", KUBE_API_SERVER, true, timeout);
+    readinessChecker.waitUntilReady(apiServerPort, "readyz", KUBE_API_SERVER, true, timeout);
     int newTimout = (int) (timeout - (System.currentTimeMillis() - startTime));
     readinessChecker.waitUntilDefaultNamespaceAvailable(apiServerPort, binaryManager, certManager,
         config, newTimout);

core/src/main/java/io/javaoperatorsdk/jenvtest/process/ProcessReadinessChecker.java

@@ -177,8 +177,13 @@ public void checkServerTrusted(
               }
           },
           null);
+      // Set protocol to HTTP/1.1 for unauthenticated invocations of "GET /readyz". Sending
+      // unauthenticated requests using HTTP/2 is problematic on Kubernetes >=1.29, which enables
+      // denial-of-service mitigation for authenticated HTTP/2 by default with the
+      // UnauthenticatedHTTP2DOSMitigation feature gate.
       return HttpClient.newBuilder()
           .sslContext(sslContext)
+          .version(HttpClient.Version.HTTP_1_1)
           .build();
     } catch (NoSuchAlgorithmException | KeyManagementException e) {
       throw new JenvtestException(e);