So it’s been a few days, where are we now?
I also thought given the technical inclination of a lot of our users that you all might be somewhat interested in the what, how and why of our decisions here, so I’ve included a bit of the more techy side of things in my update.
Bandwidth
So one of the big issues we had was the heavy bandwidth caused by a massive amount of downloaded content (not in terms of storage space, but multiple people downloading the same content).
In terms of bandwidth, we were seeing the top 10 single images resulting in around 600GB+ of downloads in a 24 hour period.
This has been resolved by setting up a frontline caching server at pictrs.blahaj.zone, which is sitting on a small, unlimited 400Mbps connection, running a tiny Caddy cache that is reverse proxying to the actual lemmy server and locally caching the images in a file store on its 10TB drive. The nginx in front of lemmy is 301 redirecting internet facing static image requests to the new caching server.
This one step alone is saving over $1,500/month.
Alternate hosting
The second step is to get away from RDS and our current fixed instance hosting to a stand-alone and self-healing infrastructure. This has been what I’ve been doing over the last few days, setting up the new servers and configuring the new cluster.
We could be doing this cheaper with a lower cost hosting provider and a less resiliant configuration, but I’m pretty risk averse and I’m comfortable that this will be a safe configuration.
I woudn’t normally recommend this setup to anyone hosting a small or single user instance, as it’s a bit overkill for us at this stage, but in this case, I have decided to spin up a full production grade kubernetes cluster with a stacked etcd inside a dedicated HA control plane.
We have rented two bigger dedicated servers (64GB, 8 CPU, 2TB RAID 1, 1 GBPS bandwidth) to run our 2 databases (main/standby), redis, etc on. Then a the control plane is running on 3 smaller instances (2GB, 2 CPU each).
All up this new infrastructure will cost around $9.20/day ($275/m).
Current infrastructure
The current AWS infrastructure is still running at full spec and (minus the excess bandwidth charges) is still costing around $50/day ($1500/m).
Migration
Apart from setting up kubernetes, nothing has been migrated yet. This will be next.
The first step will be to get the databases off the AWS infrastucture first, which will be the biggest bang for buck as the RDS is costing around $34/day ($1,000/m)
The second step will be the next biggest machine which is our Hajkey instance at Blåhaj zone, currently costing around $8/day ($240/m).
Then the pictrs installation, and lemmy itself.
And finally everything else will come off and we’ll shut the AWS account down.
Just to add some more background on this: I used to work tightly with the Network Team in the website team of the biggest contender in its market (can’t disclose which one without people figuring out the company since the market is a bit niche).
We had 20’000 Users a day with a lot of images served.
The whole infrastructure consisted of 2 Firewall servers and the main DB (pSQL) on 2 self-hosted servers (think colo, it was sitting in a very remote location with 2 big diesel generators that would’ve ran the whole datacenter for a week iirc), with 14 Hetzner backend mirrors who ran the whole PHP code, served images and the angular + some weird custom Javascript. Scaling was done by simply throwing more Hetzners at it.
Given that Lemmy runs super performance efficient in comparison to 20 year deprecated PHP code that held together with ducttape, I feel like much less could make it work.
I’m out of my depth but based on the cost savings, seems like a good situation? Kubernetes does scare me though. On the other hand it might be sensible to do this kind of overcorrection just in case the traffic takes another big spike. On the other other hand what you’re describing seems pretty dang effective.
yeah, you pretty much described the use case for k8s. It allows for rapid horizontal scaling, since you can easily throw another machine into the cluster if you need it. It mostly makes sense if you actually have multiple machines sitting idle to begin with, so this technology is mostly used in combination with managed quick rent servers (think AWS).
Beyond that, k8s is kinda fancy for cluster management, but if you don’t have a cluster you kinda don’t need it to begin with. Using simple kernel VMs (think Proxmox) or just Docker works better there. You could still go for k8s since it’s pretty much docker with cluster functionalities, just in case you want to expand eventually (sidenote, docker allows for cluster functionalities too, but they put a price on it, while k8s is open source iirc).
In that company I worked, k8s was considered but ultimately not implemented since it was considered a bit overkill. We already had everything set up with a bunch of bash scripts anyway, so it didn’t matter too greatly to begin with.
I think it’s smart to start with k8s. Better than having to switch over to it later. Since lemmy is growing and will continue to grow.
Learning k8s is the more difficult part. If you know k8s well, it’s much easier to deploy than an ec2 deployment. Especially if you need an ASG and ELBs