#Load balancer

[haroldfinch07]

Load Balancing Web Sockets with K8s/Istio

When load balancing WebSockets in a Kubernetes (K8s) environment with Istio, there are several considerations to ensure persistent, low-latency connections. WebSockets require special handling because they are long-lived, bidirectional connections, which are different from standard HTTP request-response communication. Here’s a guide to implementing load balancing for WebSockets using Istio.

1. Enable WebSocket Support in Istio

By default, Istio supports WebSocket connections, but certain configurations may need tweaking. You should ensure that:

Destination rules and VirtualServices are configured appropriately to allow WebSocket traffic.

Example VirtualService Configuration.

Here, websocketUpgrade: true explicitly allows WebSocket traffic and ensures that Istio won’t downgrade the WebSocket connection to HTTP.

2. Session Affinity (Sticky Sessions)

In WebSocket applications, sticky sessions or session affinity is often necessary to keep long-running WebSocket connections tied to the same backend pod. Without session affinity, WebSocket connections can be terminated if the load balancer routes the traffic to a different pod.

Implementing Session Affinity in Istio.

Session affinity is typically achieved by setting the sessionAffinity field to ClientIP at the Kubernetes service level.

In Istio, you might also control affinity using headers. For example, Istio can route traffic based on headers by configuring a VirtualService to ensure connections stay on the same backend.

3. Load Balancing Strategy

Since WebSocket connections are long-lived, round-robin or random load balancing strategies can lead to unbalanced workloads across pods. To address this, you may consider using least connection or consistent hashing algorithms to ensure that existing connections are efficiently distributed.

Load Balancer Configuration in Istio.

Istio allows you to specify different load balancing strategies in the DestinationRule for your services. For WebSockets, the LEAST_CONN strategy may be more appropriate.

Alternatively, you could use consistent hashing for a more sticky routing based on connection properties like the user session ID.

This configuration ensures that connections with the same session ID go to the same pod.

4. Scaling Considerations

WebSocket applications can handle a large number of concurrent connections, so you’ll need to ensure that your Kubernetes cluster can scale appropriately.

Horizontal Pod Autoscaler (HPA): Use an HPA to automatically scale your pods based on metrics like CPU, memory, or custom metrics such as open WebSocket connections.

Istio Autoscaler: You may also scale Istio itself to handle the increased load on the control plane as WebSocket connections increase.

5. Connection Timeouts and Keep-Alive

Ensure that both your WebSocket clients and the Istio proxy (Envoy) are configured for long-lived connections. Some settings that need attention:

Timeouts: In VirtualService, make sure there are no aggressive timeout settings that would prematurely close WebSocket connections.

Keep-Alive Settings: You can also adjust the keep-alive settings at the Envoy level if necessary. Envoy, the proxy used by Istio, supports long-lived WebSocket connections out-of-the-box, but custom keep-alive policies can be configured.

6. Ingress Gateway Configuration

If you're using an Istio Ingress Gateway, ensure that it is configured to handle WebSocket traffic. The gateway should allow for WebSocket connections on the relevant port.

This configuration ensures that the Ingress Gateway can handle WebSocket upgrades and correctly route them to the backend service.

Summary of Key Steps

Enable WebSocket support in Istio’s VirtualService.

Use session affinity to tie WebSocket connections to the same backend pod.

Choose an appropriate load balancing strategy, such as least connection or consistent hashing.

Set timeouts and keep-alive policies to ensure long-lived WebSocket connections.

Configure the Ingress Gateway to handle WebSocket traffic.

By properly configuring Istio, Kubernetes, and your WebSocket service, you can efficiently load balance WebSocket connections in a microservices architecture.

[redactedconcepts]

Load Balancer

Ever wonder how Facebook, Linkedin, Twitter and other web giants are handling such huge amounts of traffic? They don’t have just one server, but tens of thousands of them. In order to achieve this, web traffic needs to be distributed to these servers, and that is the role of a load-balancer.

Readme:

Load-balancing

Load-balancing algorithms

[dgruploads]

AWS | Episode 51 | Mastering AWS Application Load Balancer: Intro & Hands-On Tutorial

[rackmount-official-my-ass]

when I rant about cloudflare and the unintended centralization of the internet, here's why.

the services they provide are valuable, but organizationally centralized—of course they are geographically distributed and redundant against hardware failure, but a bad config or company policy change can cause huge problems across the internet that are both hard to diagnose and hard to mitigate. for end users who don't know what a global load balancer is, it looks like half the internet just...fell off.

[blood-starved-beast]

Seeing people say that Melinoe would be the type to reject love or love interests but like. I can see her being more polygamous than Zagreus precisely cause she's so hard-working and organized. Do you know how much work it requires to balance possibly 4 or 5 love interests? All with their own needs, personalities, vices etc.? Zagreus "my room in squalor is fine" could never.

[slaygentford]

I want everyone to know from the bottom of my heart that if a teacher assigns you group work it's because they've talked themselves into believing it's pedagogically sound to sit at their desk for twenty minutes

[wilting-fl0wer]

woe silly Mia (+ Sol) doodles be upon ye

Mia... i miss her..... i need to post her more........

[marvel-lous-guy]

Tony: here, hold this *hands Peter a wrench*

Peter: *now holding 17 different tools* I think I'm gonna drop it

Tony: You're fine

*loud clang and crash*

Peter: ...I dropped it

[exuvvium]

hot take rlcraft sucks its not enjoyable at all

[morganbritton132]

Having an office job is like, 60% waiting for a report to load.

[quizicalgin]

Now then, to the mask dress. I've already picked out most of the parts, but now it's a matter of choosing which side split to work with. The red dress would be the most accurate, although I'd have to smooth out the texture to remove the sparkle. Alternatively there's going with the super tall thigh split that's off to the side, but I remember being an even bigger nightmare to work with.

[freshthoughts2020]

[thepringlesofblood]

the new d20 trailer: escaping/surviving in the forest, ink and parchment aesthetic, all sorts of woodland creatures and you are one of them, is (probably) going to pull the genre-expectations rug out from under you as soon as it has a chance

me

[drdemonprince]

i think in the past few weeks i finally overcame the long slow soul curshing burnout i fell into after writing my last two books and breaking up with a partner of over 10 years. lately i have been feeling ENERGIZED and excited by future projects rather than bitter and resentful about needing to do anything, and im more tolerant of stimulation rather than being so extremely stress averse that i cancel anything that requires much energy. my energy is feeding into itself now. perfect time to fuck it all up by writing another book.

[fantastic-mr-corvid]

Now Tesoro is trans it complicates the hypothetical dynamics diagram* even more bc after she comes out her biggest haters [mainly Cherry] are like good for you! aw damn it now i kinda like you. But also Cherry is annoyed because she can never have her hair undyed bc otherwise the main difference between them is one tattoo, Tesoros freckles and Cherrys eyes being green.

*i forgive her for it bc its never fucking happening anyway