Docker Alternatives for When Docker Pisses You Off

The main Docker problems fall into three categories: security nightmares, licensing surprises, and random shit that breaks for no reason.

Docker Daemon Runs as Root (Security Hates This)

Every Docker container process can basically become root on your host. That's not a bug, that's how Docker works. The daemon runs as root, containers inherit those privileges.

Try explaining to security why your web app container can modify /etc/passwd on the production server. Spoiler: you can't.

NIST has a 42-page guide about why this is terrible, written in government speak that basically says "don't do this." Docker's own security docs admit this is a problem but don't fix it. The CIS Docker Benchmark has 100+ security configurations you need to implement manually - I've seen teams spend months trying to implement all of them.

I once had a junior dev accidentally wipe /var because a container mount went wrong and they had root permissions. Docker's security model makes every mistake potentially catastrophic.

Docker Desktop Isn't Free Anymore

Docker changed their licensing in 2021. Now companies over 250 employees need paid licenses - $5-21/month per developer.

Not huge money, but annoying when free alternatives exist. Finance teams love asking why you're paying for container software when Podman does the same thing for free. I've been in three budget meetings where this came up, and every time someone asks "why can't we just use the free one?"

Memory Usage Gets Weird at Scale

Docker daemon uses memory even when no containers are running. Add containers and it uses more. The memory usage pattern makes no sense and Docker's documentation doesn't explain why.

I've seen Docker daemons use 2-4GB just sitting there idle. Then when you spin up containers, memory usage jumps unpredictably. Good luck explaining that to monitoring.

Last month we had a production server with 32GB RAM run out of memory. Docker daemon was using 8GB with only three small containers running. Restarting the daemon freed up the memory, but we never figured out why it happened.

Kubernetes Dropped Docker Support

Kubernetes removed the Docker runtime interface in version 1.24. That's k8s saying "Docker daemon is too heavy for production."

Most cloud providers switched to containerd or CRI-O. Both are lighter and designed for orchestration, not developer laptops. Amazon EKS, Google GKE, and Azure AKS all use containerd now.

If you're running Docker on Kubernetes, you're using deprecated tech. I learned this the hard way when our EKS cluster stopped working after an upgrade - spent two days figuring out why all our pods were failing to start.

Network Configuration is a Mystery

Docker's bridge networking works fine for docker-compose up on your laptop. In production with multiple hosts and services, it becomes black magic.

The networking documentation assumes you understand Linux networking concepts that most developers don't know. When it breaks, the error messages don't help. I spent three days debugging a networking issue where containers couldn't talk to each other - turned out to be a subnet conflict that Docker never mentioned in the logs.

AWS charges extra for data transfer between availability zones. Docker's networking can trigger that accidentally if you don't configure it right. I've seen AWS bills jump by $500/month because of misconfigured Docker networking pulling data across zones.

Bottom line: Docker works great for development. Production is where it falls apart.

Most people don't need to care about runtimes. Docker works fine for development. But if you're hitting Docker problems or running Kubernetes, here's what actually works.

Podman - Docker Commands, No Daemon

What it does: Runs containers without a daemon process. Uses the same CLI commands as Docker.

Why it exists: Docker daemon runs as root, which security teams hate. Podman doesn't need root privileges - Red Hat developed it specifically to fix Docker's security problems.

Setup on RHEL/CentOS:

sudo dnf install podman
alias docker=podman

Setup on Ubuntu:

sudo apt install podman
alias docker=podman

What breaks: Volume mounts work differently in rootless mode. You'll hit permission errors the first time you try to mount a host directory - I guarantee it. The Podman docs cover rootless containers but don't explain why everything fails with "Permission denied."

Fix for volume mounts:

## Add your user to subuid/subgid - this fixes 90% of Podman volume issues
sudo usermod --add-subuids 100000-165535 $USER
sudo usermod --add-subgids 100000-165535 $USER
## Then log out and back in, or the changes won't take effect

When Podman containers can't access mounted files, it's always the subuid/subgid configuration. Every. Damn. Time.

Reality: Podman is faster at starting containers because there's no daemon overhead. But some Docker Compose files break because networking works differently. There's podman-compose as a workaround but it doesn't support all Compose features - learned that one trying to migrate a 15-service app.

containerd - What Kubernetes Actually Uses

What it does: Container runtime designed for orchestration systems like Kubernetes. Originally created by Docker, then donated to the CNCF when they realized it was too useful to keep proprietary.

Why Kubernetes uses it: Docker daemon is too heavy. containerd just runs containers, no extra bullshit. Kubernetes deprecated Docker because they needed something that wasn't designed for developer laptops.

Memory usage: Uses way less memory than Docker daemon - maybe 50-80% less based on what I've seen in production. Exact savings depend on how many containers you're running.

CLI tools suck: crictl is the containerd equivalent of docker commands. It's functional but the user experience is terrible. Every time I use crictl I miss Docker's CLI - it's just clunky and unintuitive.

Common commands:

## List running containers
crictl ps

## Get container logs  
crictl logs container-id

## Execute command in container
crictl exec -it container-id bash

When to use it: If you're running Kubernetes and want your development runtime to match production. All major cloud providers use containerd - it's basically the standard now.

CRI-O - Minimal Kubernetes Runtime

What it is: Container runtime that only implements the Kubernetes Container Runtime Interface. No standalone container support.

Why it exists: Even containerd has features Kubernetes doesn't need. CRI-O strips everything down to the bare minimum - Red Hat's OpenShift uses it as their default runtime.

Memory usage: Lighter than both Docker and containerd. Maybe 20-30% memory reduction based on what I've seen in OpenShift clusters.

The catch: You can't run containers outside of Kubernetes. No docker run equivalent. It's literally only for Kubernetes.

Error messages suck: When things break, CRI-O gives you useless error messages like "container create failed." Debugging CRI-O issues is like pulling teeth - the logs tell you nothing useful.

When to use it: OpenShift clusters or when you want maximum resource efficiency in Kubernetes.

gVisor - Paranoid Security

What it does: Runs containers inside a userspace kernel that intercepts all system calls. Google developed gVisor for their own paranoid container security needs.

Security model: Container breakout gets you access to gVisor's fake kernel, not the real host. It's like adding another layer of protection, but with overhead.

Performance cost: Everything runs 15-20% slower. I/O is especially bad - expect your database queries to take longer. Google's own benchmarks admit there's significant overhead.

When you need it: Running untrusted code, multi-tenant environments, or when compliance folks demand container isolation. AWS Firecracker provides similar security with better performance.

GKE integration: Google Cloud supports gVisor through "sandbox" node pools. Works but containers take forever to start - I've seen 30-second startup times.

Debugging problems: When your app breaks inside gVisor, stack traces point to gVisor code instead of your application. Good luck figuring out what's actually wrong with your app.

Which One Should You Use?

For development: Podman if you want to avoid Docker licensing. Docker if you don't care.

For Kubernetes: containerd if you want standard tooling. CRI-O if you want maximum efficiency.

For security: gVisor if you're running untrusted code. Everything else if you trust your containers.

For simplicity: Docker is still the easiest. Only switch if you have specific problems Docker can't solve.