Hi, I’m sysarcher

Retiring snapshot-per-write for an event-fed read model TL;DR: Shakespeare succinctly describes what will follow, but our history storage mechanism was worse than O(N) — we were writing a whole copy of everything on every change. We moved to using events and an event-driven architecture. This is very much appreciated by our DB. Event-driven systems are an aggregation of the past — what’s past, is prologue! (The Tempest, Act II) I discuss this topic very briefly here as well (2018 video): https://youtu.be/-VJ6FtTS8zg ...

When Sara is taking her exam, the last thing she has on her mind is whether clicking “submit” will actually work. The exam ends: in the last two minutes of the window, most of the class hits submit at the same time. It’s not only the class — these are central exams, everyone in the country is submitting at the same time. When the system shows “Submitted”, this is a promise to Sara that her exam is now safely stored with it and she doesn’t need to worry. ...

So I’m applying for a startup funding to YC. And I wanted to share this pic with them. Will update stuff here later.

One of the pains of playing around with Metrics server is that it sometimes doesn’t connect to the node. In my case it was unhealthy and complaining about x509 certs. Not for prod but here’s a resolution: Install Metrics Server kubectl apply -f https://github.com/kubernetes-sigs/metrics-server/releases/download/v0.6.4/components.yaml Apply the patch: kubectl -n kube-system patch deployment metrics-server --type=json \ -p='[{"op": "add", "path": "/spec/template/spec/containers/0/args/-", "value": "--kubelet-insecure-tls"}]]' thanks to @awalker125

Strategy: What I’m doing is unblock/whitelist any domain that causes video playback issues. (Credits for the original list @beshrkayali) I have started to add to a blacklist here: I also created a regex which I’m experimenting with: ^r[0-9]{1,2}-{3}sn-h0je[a-z0-9]*.googlevideo.com I tested this RegEx on regex101.com with the following data: r4---sn-h0jeener.googlevideo.com r4---sn-h0jeener.googlevideo.com r4---sn-h0jeln7l.googlevideo.com r1---sn-h0jelne7.googlevideo.com r2---sn-h0jeln7e.googlevideo.com r1---sn-h0jeln7e.googlevideo.com r3---sn-h0jeenle.googlevideo.com r1---sn-h0jeenle.googlevideo.com r5---sn-h0jeened.googlevideo.com r1---sn-h0jeenek.googlevideo.com r5---sn-h0jeln7l.googlevideo.com r2---sn-h0jeenle.googlevideo.com r1---sn-h0jeln7e.googlevideo.com r5---sn-h0jeen76.googlevideo.com r5---sn-h0jeln7y.googlevideo.com r5---sn-h0jeenek.googlevideo.com r5---sn-h0jeened.googlevideo.com r5---sn-h0jelne7.googlevideo.com r1---sn-h0jeener.googlevideo.com r4---sn-h0jeln7l.googlevideo.com r1---sn-h0jelne7.googlevideo.com r4---sn-h0jeln7r.googlevideo.com r2---sn-h0jeenek.googlevideo.com r6---sn-h0jeen76.googlevideo.com r3---sn-h0jeener.googlevideo.com r1---sn-h0jelne7.googlevideo.com

Linux only DISCLAIMER: THE FOLLOWING CAN LEAD TO CREATING SECURITY HOLES IN THE VPN-PROTECTED NETWORK… BE VERY CAREFUL. MAKE SURE YOU KNOW WHAT YOU’RE DOING. IF YOU DON’T UNDERSTAND WHAT YOU’RE DOING, DO NOT PROCEED VPNs are a pain in the neck. I managed to find a way to have VPN traffic limited to some sites instead of routing everything through your corporate network. Routing everything through corporate network is also a cause of load on the company’s servers. Imagine a ton of people watching Youtube over VPN. Now, I’m talking about traditional VPN here, not p2p stuff. ...

QEMU/KVM are a popular backend for OpenStack. In StarlingX Openstack (stx-openstack) this is also the case. I’ll try to describe various techniques that I used to optimize RT behavior on an STX 4.0.1 cluster with worker nodes. Terminology Bare-Metal is a a physical computer and it’s base OS Host is a bare-metal machine that runs VMs Thread is a core of a CPU CPU thread refers to the thread on the host system CPU ...

StarlingX is continuing to evolve and update it’s Real-time capabilities but documentation can be a bit sparse. This page is hopefully a placeholder for until we have a great documentation around the capabilities. Isolating CPU Cores In a StarlingX cluster CPU isolation and Kernel commandline parameters are (generally) managed from the active controller through system host-cpu-XXX commands. For isolation, we have the Application-isolated assigned_function. Get current functions: $ system host-cpu-list controller-0 +--------------------------------------+----------+-----------+----------+--------+-----------------------------------------+-------------------+ | uuid | log_core | processor | phy_core | thread | processor_model | assigned_function | +--------------------------------------+----------+-----------+----------+--------+-----------------------------------------+-------------------+ | 65b8337e-08bf-4e32-b7e6-17505eaf0806 | 0 | 0 | 0 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Platform | | b7578ba2-cba0-46cd-b860-3ba5c03ba91d | 1 | 0 | 1 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Platform | | ff7447a2-00df-43db-8716-d1416faf89bc | 2 | 0 | 2 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 142796e5-b17d-48e9-b18a-b84c1ea5ae37 | 3 | 0 | 3 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | c68a8dc7-367f-4512-84ca-ec559fbb63f4 | 4 | 0 | 4 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 15f360e2-d27c-4d9a-b0ff-0b78387eeb8c | 5 | 0 | 5 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 89274cb5-4fb5-4f5b-a8c5-ec36394b5ce5 | 6 | 0 | 6 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 33fb1e8e-77cd-4334-b061-dd40e6b7f7ba | 7 | 0 | 7 | 0 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 8c804a31-c61e-408c-83c4-3c7192a861d8 | 8 | 0 | 0 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Platform | | 560ad09d-48df-42ec-8588-7e739030d7e3 | 9 | 0 | 1 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Platform | | cbd83713-0118-4995-9810-486cfdbb912e | 10 | 0 | 2 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | cb45713a-fa51-4628-b536-e3d5d57c891e | 11 | 0 | 3 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 28dff3de-9913-4055-89d5-09dfc084c3c1 | 12 | 0 | 4 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 98cf6c9e-2717-4f88-b487-487dbdadd18e | 13 | 0 | 5 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 73dcec10-7a62-4d07-ba23-3482d0e0f2af | 14 | 0 | 6 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | | 4a5a4477-f0db-4d77-9a6a-c77e5ca292e4 | 15 | 0 | 7 | 1 | Intel(R) Xeon(R) D-2146NT CPU @ 2.30GHz | Application | +--------------------------------------+----------+-----------+----------+--------+-----------------------------------------+-------------------+ The system host-cpu-modify command is used to modify the assigned function. ...

I use Vim a lot. And if you’re a productive user of Vim, you will definitely appreciate the following remaps: ESC: I have remapped the Escape key to CAPSLOCK. Who uses CapsLock? ESC on the other hand is a Vim user’s go-to reflex. So keep it close-by. ESC+HJKL: For navigation. Why would you use muscles to move over to the arrow keys when you have them under your fingers. How-to xmodmap can be used to modify these key settings. But I think it will only work for X-sessions. ...

I have spent time looking at edge deployments of kubernetes, especially, those that are managed by the Ops team in an industry 4.0 setting. Here are my candidates: KubeEdge k3s and k3os StarlingX I present my brief impressions of each below. This post will need updates as my research goes on. Background Edge is often used as a vague term for either one of CDN, factory network or IT data center. There is a fair amount of confusion where cloud transforms into “Edge”. ...