[Bug] Misuse of Docker API and misunderstanding of Ray HA cause test_ray_serve flaky

tests/compatibility-test.py

@@ -174,99 +174,50 @@ def test_kill_head(self):
         assert rtn == 0
 
     def test_ray_serve(self):
-        client = docker.from_env()
-        container = client.containers.run(ray_image, remove=True, detach=True, stdin_open=True, tty=True,
-                                          network_mode='host', command=["/bin/sh", "-c", "python"])
-        s = container.attach_socket(
-            params={'stdin': 1, 'stream': 1, 'stdout': 1, 'stderr': 1})
-        s._sock.setblocking(0)
-        s._sock.sendall(b'''
-import ray
-import time
-import ray.serve as serve
-import os
-import requests
-from ray._private.test_utils import wait_for_condition
+        docker_client = docker.from_env()
+        container = docker_client.containers.run(ray_image, remove=True, detach=True, stdin_open=True, tty=True,
+                                          network_mode='host', command=["/bin/sh"])
+        # Deploy a model with ray serve
+        ray_namespace = ''.join(random.choices(string.ascii_lowercase, k=10))
+        logger.info(f'namespace: {ray_namespace}')
 
-def retry_with_timeout(func, count=90):
-    tmp = 0
-    err = None
-    while tmp < count:
-        try:
-            return func()
-        except Exception as e:
-            err = e
-            tmp += 1
-    assert err is not None
-    raise err
+        utils.copy_to_container(container, 'tests/scripts', '/usr/local/', 'test_ray_serve_1.py')
+        exit_code, _ = utils.exec_run_container(container, f'python3 /usr/local/test_ray_serve_1.py {ray_namespace}', timeout_sec = 180)
 
-ray.init(address='ray://127.0.0.1:10001')
+        if exit_code != 0:
+            raise Exception(f"There was an exception during the execution of test_ray_serve_1.py. The exit code is {exit_code}." +
+                "See above for command output. The output will be printed by the function exec_run_container.")
 
-@serve.deployment
-def d(*args):
-    return f"{os.getpid()}"
-
-d.deploy()
-pid1 = ray.get(d.get_handle().remote())
-
-print('ready')
-        ''')
-
-        count = 0
-        while count < 90:
-            try:
-                buf = s._sock.recv(4096)
-                logger.info(buf.decode())
-                if buf.decode().find('ready') != -1:
-                    break
-            except Exception as e:
-                pass
-            time.sleep(1)
-            count += 1
-        if count >= 90:
-            raise Exception('failed to run script')
-
-        # kill the gcs on head node. If fate sharing is enabled
-        # the whole head node pod will terminate.
-        utils.shell_assert_success(
-            'kubectl exec -it $(kubectl get pods -A| grep -e "-head" | awk "{print \\$2}") -- /bin/bash -c "ps aux | grep gcs_server | grep -v grep | awk \'{print \$2}\' | xargs kill"')
-        # wait for new head node getting created
-        time.sleep(10)
-        # make sure the new head is ready
-        utils.shell_assert_success(
-            'kubectl wait --for=condition=Ready pod/$(kubectl get pods -A | grep -e "-head" | awk "{print \$2}") --timeout=900s')
-
-        s._sock.sendall(b'''
-def get_new_value():
-    return ray.get(d.get_handle().remote())
-pid2 = retry_with_timeout(get_new_value)
-
-if pid1 == pid2:
-    print('successful: {} {}'.format(pid1, pid2))
-    sys.exit(0)
-else:
-    print('failed: {} {}'.format(pid1, pid2))
-    raise Exception('failed')
-        ''')
-
-        count = 0
-        while count < 90:
-            try:
-                buf = s._sock.recv(4096)
-                logger.info(buf.decode())
-                if buf.decode().find('successful') != -1:
-                    break
-                if buf.decode().find('failed') != -1:
-                    raise Exception('test failed {}'.format(buf.decode()))
-            except Exception as e:
-                pass
-            time.sleep(1)
-            count += 1
-        if count >= 90:
-            raise Exception('failed to run script')
+        # Initialize k8s client
+        config.load_kube_config()
+        k8s_api = client.CoreV1Api()
+
+        # KubeRay only allows at most 1 head pod per RayCluster instance at the same time. In addition,
+        # if we have 0 head pods at this moment, it indicates that the head pod crashes unexpectedly.
+        headpods = utils.get_pod(k8s_api, namespace='default', label_selector='rayNodeType=head')
+        assert(len(headpods.items) == 1)
+        old_head_pod = headpods.items[0]
+        old_head_pod_name = old_head_pod.metadata.name
+        restart_count = old_head_pod.status.container_statuses[0].restart_count
+
+        # Kill the gcs_server process on head node. If fate sharing is enabled, the whole head node pod
+        # will terminate.
+        exec_command = ['pkill gcs_server']
+        utils.pod_exec_command(k8s_api, pod_name=old_head_pod_name, namespace='default', exec_command=exec_command)
+
+        # Waiting for all pods become ready and running.
+        utils.wait_for_new_head(k8s_api, old_head_pod_name, restart_count, 'default', timeout=300, retry_interval_ms=1000)
+
+        # Try to connect to the deployed model again
+        utils.copy_to_container(container, 'tests/scripts', '/usr/local/', 'test_ray_serve_2.py')
+        exit_code, _ = utils.exec_run_container(container, f'python3 /usr/local/test_ray_serve_2.py {ray_namespace}', timeout_sec = 180)
+
+        if exit_code != 0:
+            raise Exception(f"There was an exception during the execution of test_ray_serve_2.py. The exit code is {exit_code}." +
+                "See above for command output. The output will be printed by the function exec_run_container.")
 
         container.stop()
-        client.close()
+        docker_client.close()
 
     def test_detached_actor(self):
         docker_client = docker.from_env()

tests/scripts/test_ray_serve_1.py

@@ -0,0 +1,23 @@
+import requests
+from starlette.requests import Request
+import ray
+from ray import serve
+import time
+import sys
+
+# 1: Define a Ray Serve model.
+@serve.deployment(route_prefix="/")
+class MyModelDeployment:
+    def __init__(self, msg: str):
+        self._msg = msg
+
+    def __call__(self):
+        return self._msg
+
+ray.init(address='ray://127.0.0.1:10001', namespace=sys.argv[1])
+# 2: Deploy the model.
+handle = serve.run(MyModelDeployment.bind(msg="Hello world!"))
+# 3: Query the deployment and print the result.
+val = ray.get(handle.remote())
+print(val)
+assert(val == "Hello world!")

tests/scripts/test_ray_serve_2.py

@@ -0,0 +1,22 @@
+import ray
+import time
+import sys
+from ray import serve
+
+def retry_with_timeout(func, timeout=90):
+    err = None
+    for _ in range(timeout):
+        try:
+            return func()
+        except BaseException as e:
+            err = e
+        finally:
+            time.sleep(1)
+    raise err
+
+retry_with_timeout(lambda: ray.init(address='ray://127.0.0.1:10001', namespace=sys.argv[1]))
+retry_with_timeout(lambda:serve.start(detached=True))
+val = retry_with_timeout(lambda: ray.get(serve.get_deployment("MyModelDeployment").get_handle().remote()))
+print(val)
+assert(val == "Hello world!")
+