Question on SSL traffic between podman containers and clients (should I run k3s?)
Question on SSL traffic between podman containers and clients (should I run k3s?)
Hi everyone.
I was trying to research about how to implement SSL on the traffic between my clients and the containers that I host on my server.
Basically, my plan was to use upstream SSL in HAProxy to attempt to achieve this, but in order for that to work, each individual container on my server needs to be able to decrypt SSL. I do not think that is possible and that every container has the necessary libraries for it. This puts a halt on my idea for upstream encryption of traffic from my reverse-proxy to my containers.
With that said, ChatGPT suggested I use Kubernetes with a service mesh like Istio. The idea was intriguing so I started to read about it; but before I dive head-first into using k3s (TBH it's overkill for my setup), is there any way to implement server-side encryption with podman containers and a reverse-proxy?
After writing all of this, I think I'm missing the point about a reverse-proxy being an SSL termination endpoint, but if my question makes sense to you, please let me know your thoughts!
Thanks!
The mesh proxy would work, but it's not easy to configure and for somewhat little benefit, especially if they're all running on the same box. The way that'd work is, NGINX would talk to the mesh proxy which would encrypt it to the other mesh proxy for the target container, and then it would talk to the container unencrypted again. You talk to 3 containers and still end up unencrypted.
Unless you want TLS between nodes and containers, you can skip the intermediate step and have NGINX talk directly to the containers plaintext. That's why it's said to do TLS termination: the TLS session ends at that reverse proxy.
3Thanks. As another commenter mentioned, I'm planning to deploy a reverse proxy for every pod. I'm hoping this is OK
1
I’m missing the point about a reverse-proxy being an SSL termination endpoint
Yes, that's usually one of the jobs of the reverse proxy. Communication between the RP and an application container running on the same host is typically unencrypted. If you're really paranoid about a rogue process intercepting HTTP connections between the RP and the application container, setup separate container networks for each application, and/or use unix sockets.
ChatGPT suggested I use Kubernetes
wtf...
3Hey, thanks for your comment. Could you explain a bit more about how using Unix sockets would improve my security posture here (in terms of not having unencrypted traffic on the network)? I will think about creating separate namespaces in podman.
Good thing I asked haha. Is the fact that I mentioned ChatGPT setting a wrong impression? I like to go and ask about such questions to ChatGPT/Bing, sometimes they give wonderful answers, sometimes, not the best. Like this one. I thought that there must be an easier way to secure my traffic/do as much as possible to restricting it without jumping straight to k3s.
Thanks!
2Nothing wrong with asking LLM's about topics, I'd even say it's a good idea instead of directly asking on a forum. Just like searching before asking, asking an LLM before asking humans is good.
And mentioning where you got the recommendation for k8s is also helpful. I'm not knowledgeable about k8s, but I guess the "wtf" was about the overkill of recommending k8s when simpler solutions exist.
Unix sockets have permissions like any file, so it's simple to restrict access to a user/group and thus process running as the user. If it's unencrypted http on a server other processes could listen on localhost, but I'm unsure about that part.
4Is the fact that I mentioned ChatGPT setting a wrong impression?
Not at all, but the fact that it suggested jumping straight to k8s for such a trivial problem is... interesting.
how using Unix sockets would improve my security posture here
Unix sockets enforce another layer of protection by requiring the user/application writing/reading to/from them to have a valid UID or be part of the correct group (traditional Linux/Unix permission system). Whereas using plain localhost HTTP networking, a rogue application could somehow listen on the loopback interface and/or exploit a race condition to bind the port and prentend to be the "real" application. Network namespaces (which container management tools use to create isolated virtual networks) mostly solve this problem. Again, basic unencrypted localhost networking is fine for a vast majority of use cases/threat models.
3
if I'm understanding your question correct, you are trying to use tls on containers that may not have tls libraries?
there are two ways to that. one is to rebuild every container by yourself modifying its services to contain tls. the other is to use a pod. you put your service container and a reverse proxy into the same pod, setup that reverse proxy correctly as an edge proxy terminating tls, and expose only the reverse proxy's port. that way, it will just look like a service with tls enabled.
since you are considering tls for everyone, I assume that you don't care about overheads. adding a reverse proxy in front of every container is like 10-50MB of additional memory, and it won't matter on modern systems.
2Thank you, this is an excellent idea. I will probably not run a pod for every container (technically I can, since Netavark is supported for rootless containers in Podman 4.0), but I will definitely have a few pods on my system, where I can definitely use a reverse-proxy for every pod. Just need to figure out how I can automate it.
Thanks again
1Single node k3s is possible and can do what you’re asking but has some overhead (hence your acknowledgment of overkill). One thing i think it gets right and would help here is the reverse proxy service. It’s essentially a single entity with configuration of all of your endpoints in it. It’s managed programmatically so additions or changes are not needed to he done by hand. It sounds like you need a reverse proxy to terminate the TLS then ingress objects defined to route to individual containers/pods. If you try for multiple reverse proxies you will have a bad time managing all of that overhead. I strongly recommend going for a single reverse proxy setup unless you can automate the multiple proxies setup.
2
Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I've seen in this thread:
Fewer Letters More Letters HTTP Hypertext Transfer Protocol, the Web HTTPS HTTP over SSL SSL Secure Sockets Layer, for transparent encryption TLS Transport Layer Security, supersedes SSL k8s Kubernetes container management package
5 acronyms in this thread; the most compressed thread commented on today has 9 acronyms.
[Thread #264 for this sub, first seen 6th Nov 2023, 14:30] [FAQ] [Full list] [Contact] [Source code]
1