Kubernetes socket timeout

seems impossible. confirm. agree with..

Kubernetes socket timeout

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I'm trying to configure an HAProxy ingress controller to load-balance properly connections to websocket. I tried to raise the value timeout-client, timeout-server and timeout-connect but without success. I haven't found confirmation about websockets support in the HAProxy documentation, but this post on Quora stated that it works great.

If you have more than one ingress in the cluster you may need to specify a proxy class in the annotation for every Ingress object that should be used by HAProxy ingress:. Learn more. Asked 1 year, 2 months ago. Active 1 year, 1 month ago. Viewed 1k times. Quijote Quijote 33 5 5 bronze badges. Could you check if you can successfully connect with websocket client directly to the pod and to the service app-test ClusterIP?

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It seems to me that the HAProxy does not recognize websocket. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.

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The kubelet uses liveness probes to know when to restart a container. For example, liveness probes could catch a deadlock, where an application is running, but unable to make progress. Restarting a container in such a state can help to make the application more available despite bugs.

The kubelet uses readiness probes to know when a container is ready to start accepting traffic. A Pod is considered ready when all of its containers are ready. One use of this signal is to control which Pods are used as backends for Services. When a Pod is not ready, it is removed from Service load balancers.

The kubelet uses startup probes to know when a container application has started. This can be used to adopt liveness checks on slow starting containers, avoiding them getting killed by the kubelet before they are up and running. You need to have a Kubernetes cluster, and the kubectl command-line tool must be configured to communicate with your cluster. If you do not already have a cluster, you can create one by using Minikubeor you can use one of these Kubernetes playgrounds:. Many applications running for long periods of time eventually transition to broken states, and cannot recover except by being restarted.

Kubernetes provides liveness probes to detect and remedy such situations. In this exercise, you create a Pod that runs a container based on the k8s. Here is the configuration file for the Pod:. In the configuration file, you can see that the Pod has a single Container. The periodSeconds field specifies that the kubelet should perform a liveness probe every 5 seconds. The initialDelaySeconds field tells the kubelet that it should wait 5 seconds before performing the first probe.

If the command succeeds, it returns 0, and the kubelet considers the container to be alive and healthy. If the command returns a non-zero value, the kubelet kills the container and restarts it.Edit This Page.

It can register the node with the apiserver using one of: the hostname; a flag to override the hostname; or specific logic for a cloud provider. The kubelet works in terms of a PodSpec. The kubelet takes a set of PodSpecs that are provided through various mechanisms primarily through the apiserver and ensures that the containers described in those PodSpecs are running and healthy.

Other than from an PodSpec from the apiserver, there are three ways that a container manifest can be provided to the Kubelet. File: Path passed as a flag on the command line. Files under this path will be monitored periodically for updates.

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The monitoring period is 20s by default and is configurable via a flag. This endpoint is checked every 20 seconds also configurable with a flag. Thanks for the feedback. If you have a specific, answerable question about how to use Kubernetes, ask it on Stack Overflow. Open an issue in the GitHub repo if you want to report a problem or suggest an improvement.

Use these at your own risk. Requests that are not rejected by another authentication method are treated as anonymous requests. Anonymous requests have a username of system:anonymous, and a group name of system:unauthenticated. Due to legacy concerns, it will follow the standard CLI deprecation timeline before being removed. Valid options are AlwaysAllow or Webhook. Use the first one that exists. If the file specified by --kubeconfig does not exist, the bootstrap kubeconfig is used to request a client certificate from the API server.

On success, a kubeconfig file referencing the generated client certificate and key is written to the path specified by --kubeconfig. The client certificate and key file will be stored in the directory pointed by --cert-dir.

If --tls-cert-file and --tls-private-key-file are provided, this flag will be ignored. This is handled by the container runtime on a best effort basis.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Already on GitHub? Sign in to your account. Problem : The current client-go code relies on the underlying kernel TCP stack to determine when its connection to an apiserver has dropped.

When the connection is terminated gracefully this is not a problem and happens immediately, but in the case of the Kubelet becoming partitioned on the network, this can take upwards of 15 minutes. During this time, no reconnection attempts can occur and the following happens:. I disagree with this being the behaviour for "steady state" operations like scaling, but I doubt AWS are going to fix this. Anyway it is always possible for a node to die unexpectedly so this is something k8s should handle.

This situation has caused several complete production outages for us where the majority of the cluster was marked as NotReady. This is clearly completely disastrous. It is aso configurable for other users of client-go but not default. While this timeout is specified in RFCit is not implemented on all platforms and is not exposed by the Go standard library. Therefore, this option is platform-dependent. I have implemented support for Linux which I would guess accounts for the overwhelming majority of k8s deployments and Darwin.

Some platforms do have support for this option eg. Windows but I have no good way to test it and haven't yet implemented it, and others eg. FreeBSD have no support at all.

kubernetes socket timeout

On balance though, I think at least having this functionality on Linux is a good thing.In today's highly distributed word, where monolithic architectures are increasingly replaced with multiple, smaller, interconnected services for better or worseproxy and load balancing technologies seem to have a renaissance. Beside the older players, there are several new proxy technologies popping up in recent years, implemented in various technologies, popularizing themselves with diferent features, such as easy integration to certain cloud providers "cloud-native"high performance and low memory footprint, or dynamic configuration.

All of these technologies have different feature sets, and are targeting some specific scenarios or hosting environments for example Linkerd is fine-tuned for being used in Kubernetes. In this post I'm not going to do a comparison of these, but rather just focus on one specific scenario: how to use Envoy as a load balancer for a service running in Kubernetes.

It's high-performant, has a low resource footprint, it supports dynamic configuration managed by a "control plane" API, and provides some advanced features such as various load balancing algorithms, rate limiting, circuit braking, and shadow mirroring.

Kubernetes Tutorial: Why do you need StatefulSets in Kubernetes?

Before starting to use Envoy, I was accessing my service in Kubernetes through a service object of the type LoadBalancerwhich is a pretty typical way to access services from the outside in Kubernetes. The exact way a load balancer service works depends on the hosting environment—if it supports it in the first place. I was using the Google Kubernetes Engine, where every load balancer service is mapped to a TCP-level Google Cloud load balancer, which only supports a round robin load balancing algorithm.

Due to the above characteristics, the round robin load balancing algorithm was not a good fit, because often—by chance—multiple requests ended up on the same node, which made the average response times much worse than what the cluster would've been capable achieving, given a more uniformly spred out load.

In the remainder of this post I will describe the steps necessary to deploy Envoy to be used as a load balancer in front of a service running in Kubernetes. A headless service doesn't provide a single IP and load balancing to the underlying pods, but rather it just has DNS configuration which gives us an A record with the pod's IP address for all the pods matching the label selector.

This service type is intended to be used in scenarios when we want to implement load balancing, and maintaining the connections to the upstream pods ourselves, which is exactly what we can do with Envoy.

We can create a headless service by setting the. So assuming that our application pods have the label app with the value myappwe can create the headless service with the following yaml. The name of the Service does not have to be equal to the name of our application nor the app label, but it's a good convention to follow. If we have 3 pods, we'll see a DNS summary similar to this. The simplest way to use Envoy without providing the control plane in the form of a dynamic API is to add the hardcoded configuration to a static yaml file.

The following is a basic configuration that load balances to the IP addresses given by the domain name myapp. You can find more information about the various config parameters in the docs. Now we have to put the following Dockerfile next to the envoy. The last step is building the image, and pushing it somewhere like the Docker hub, or the container registry of a cloud provider to be able to use it from Kubernetes. Assuming I'd like to push this to my personal Docker hub account, I could do it with the following commands.

If we'd like to be able to customize some parts of the Envoy configuration with environment variables without rebuilding the Docker image, we can do some env var substitution in the yaml config. Let's say we'd like to be able to customize the name of the headless service we're proxying to, and the load balancer algorithm, then we'd have to modify the yaml config the following way. Then implement a little shell script docker-entrypoint. Keep in mind that if you use this approach, you have to specify these env vars in the Kubernetes deployment, otherwise they will be empty.

After applying this yaml, the Envoy proxy should be operational, and you can access the underlying service by sending the requests to the main port of the Envoy service.

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In this example I only added a service of type ClusterIP, but you can also use a LoadBalancer service, or an Ingress object if you want to access the proxy from outside the cluster. The image only shows one single Envoy pod, but you can scale it up to have more instances if necessary.

And of course you can use a Horizontal Pod Autoscaler to automatically create more replicas as needed. All instances will be autonomous and independent of each other. In practice you'll probably need much fewer instances for the proxy than for the underlying service.

In the Envoy configuration file you can see an admin: section, which configures Envoy's admin endpoint. That can be used for checking various diagnostic information about the proxy. If you don't have a service publishing the admin port— by default—you can still access it by port-forwarding to a pod with kubectl. Assuming that one of the Envoy pods is called myapp-envoyc8d5fff-mwff8then you can start port-fowarding with the command kubectl port-forward myapp-envoyc8d5fff-mwff8 One way to do monitoring is to use Prometheus to scrape the stats from the proxy pods.

You can download a Grafana dashboard visualizing these metrics from this repositorywhich will give you a set of graphs to the following. The load balancing algorithm can have significant effect on the overall performance of our cluster.

Using a least request algorithm can be beneficial with services for which an even spread of the load is necessary, for example when a service is CPU-intensive, and gets easily overloaded.I often get issues like this: java. One single issue breaks the entire task and makes it hard to even cancel the task. Should this not be retried rather than break execution?

Our Jenkins will run longer running tasks as well. Any single task breaking stop in the middle is a real issue, and I don't see why one network issue after successful ones in this case is such a big issue.

SocketTimeoutException: timeout.

Kubernetes Liveness and Readiness Probes: How to Avoid Shooting Yourself in the Foot

CloudBees-internal issue. We configured -Dkubernetes. I'll report back if it helps or not. That option helped for us. But the reason why the pings started to fail was actually the JVM garbage collector, which caused the master to hang for more than 1 second. We switched from the default to G1GC to reduce time the master is blocked, and this helped with other timeouts too. I believe that this issue is resolved since the release of version 1.

Issues Reports Components Test sessions. Log In. XML Word Printable. Type: Bug. Status: Open View Workflow. Priority: Major.

Resolution: Unresolved. Labels: timeout. Environment: Jenkins version: 2. Similar Issues:.

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Issue Links. SocketTimeoutException: timeout Resolved. Hide Permalink. Deiwin Sarjas added a comment - Tyrone Grech added a comment - We are also encountering this issue fairly often in our CI system running: On premises Kubernetes cluster on version 1.

Show Tyrone Grech added a comment - We are also encountering this issue fairly often in our CI system running: On premises Kubernetes cluster on version 1.

Show Deiwin Sarjas added a comment - We configured -Dkubernetes. Created: Updated: Kubernetes liveness and readiness probes can be used to make a service more robust and more resilient, by reducing operational issues and improving the quality of service.

However, if these probes are not implemented carefully, they can severely degrade the overall operation of a service, to a point where you would be better off without them. In this article, I will explore how to avoid making service reliability worse when implementing Kubernetes liveness and readiness probes.

While the focus of this article is on Kubernetes, the concepts I will highlight are applicable to any application or infrastructural mechanism used for inferring the health of a service and taking automatic, remedial action. Kubernetes uses liveness probes to know when to restart a container.

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If a container is unresponsive—perhaps the application is deadlocked due to a multi-threading defect—restarting the container can make the application more available, despite the defect.

It certainly beats paging someone in the middle of the night to restart a container. Kubernetes uses readiness probes to decide when the container is available for accepting traffic.

kubernetes socket timeout

The readiness probe is used to control which pods are used as the backends for a service. A pod is considered ready when all of its containers are ready. If a pod is not ready, it is removed from service load balancers. For example, if a container loads a large cache at startup and takes minutes to start, you do not want to send requests to this container until it is ready, or the requests will fail—you want to route requests to other pods, which are capable of servicing requests.

kubernetes socket timeout

At the time of this writing, Kubernetes supports three mechanisms for implementing liveness and readiness probes: 1 running a command inside a container, 2 making an HTTP request against a container, or 3 opening a TCP socket against a container.

A probe has a number of configuration parameters to control its behaviour, like how often to execute the probe; how long to wait after starting the container to initiate the probe; the number of seconds after which the probe is considered failed; and how many times the probe can fail before giving up. For a liveness probe, giving up means the pod will be restarted. For a readiness probe, giving up means not routing traffic to the pod, but the pod is not restarted.

Deploying to Kubernetes

Liveness and readiness probes can be used in conjunction. The Kubernetes documentation, as well as many blog posts and examples, somewhat misleadingly emphasizes the use of the readiness probe when starting a container. This is usually the most common consideration—we want to avoid routing requests to the pod until it is ready to accept traffic.

However, the readiness probe will continue to be called throughout the lifetime of the container, every periodSecondsso that the container can make itself temporarily unavailable when one of its dependencies is unavailable, or while running a large batch job, performing maintenance, or something similar. If you do not realize that the readiness probe will continue to be called after the container is started, you can design readiness probes that can result in serious problems at runtime.

Even if you do understand this behaviour, you can still encounter serious problems if the readiness probe does not consider exceptional system dynamics.

kubernetes socket timeout


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