We run a high-availability HAProxy cluster at the very edge of our infrastructure to route incoming traffic to our app tiers. It's a classic active/passive setup using Keepalived with a floating virtual IP (VIP) to handle instant failover. Debian is our absolute go-to for anything network-heavy like this because of its stability, and we use this pre-hardened image as the base for the nodes in the cluster.
Hardened debian cluster has simplified edge load balancing and has reduced security maintenance
What is our primary use case?
How has it helped my organization?
Honestly, it just took a massive chunk of recurring maintenance off our plate. Because our load balancers are directly exposed to public traffic, we used to spend a significant amount of time updating Packer templates, patching packages, and double-checking CIS compliance rules. Switching to this AMI meant the hardening was already baked in and kept up-to-date by ClearScale. Our security audits are now a breeze because we don't have to defend our own custom OS tweaks anymore.
What is most valuable?
Debian's core stability under massive network stress has been the real highlight. Running high-throughput load balancers requires predictable TCP performance and zero memory leaks. This image is incredibly clean with no background bloatware eating up memory or CPU cycles, allowing HAProxy to run at maximum efficiency with super low latency. We didn't have to spend any time doing custom kernel or network-level tuning to get top-tier performance.
What needs improvement?
A slimmed-down 'minimal' build option for this Debian 13 release would be fantastic for minimizing the attack surface even further.
For how long have I used the solution?
We've been running ClearScale Debian in production for about six months. But our team has used Debian in general for over ten years.
Which solution did I use previously and why did I switch?
We used to spin up different vendors' Debian AMIs and run a massive Ansible playbook at launch to strip out packages, lock down SSH, and set up the local firewalls. It worked, but it was slow, fragile, and we had to constantly maintain the script as Debian evolved. We switched to this AMI to get that hardening out-of-the-box, which made our deployment workflows much faster and less prone to failures.
What's my experience with pricing, setup cost, and licensing?
Since we only run a small cluster of edge load balancers rather than a massive fleet of app servers, the hourly license premium is basically a rounding error on our AWS bill. For critical gateway infrastructure, paying a few cents extra per hour to have a verified hardened base OS is extremely cheap insurance.
Which other solutions did I evaluate?
We considered a few routes: sticking with the standard AWS AMIs and building our own Packer pipeline, or evaluating older Ubuntu releases. We stuck with Debian because of its reputation for rock-solid networking, and chose the ClearScale version because the math made sense. Their hourly markup is way cheaper than having our senior engineers build, test, and audit custom base images ourselves.
What other advice do I have?
If you are setting up Keepalived for high availability, remember to explicitly allow VRRP protocol in your firewall config before starting the service. If you don't, both of your HAProxy nodes will think they are the active master and you'll end up with a split-brain scenario. Once you have that rule in place, it’s a beautifully quiet and stable setup.
If public cloud, private cloud, or hybrid cloud, which cloud provider do you use?
Amazon Web Services (AWS)
