Why does shared hosting keep hitting memory limits, even after you upgrade? Shared hosting pools CPU and RAM across every account on the same physical server. A plan upgrade within shared hosting usually buys you a higher quota on that shared pool, not a guaranteed, isolated allocation — so Docker containers still get OOM-killed and pages still load slowly once your actual usage bumps into the pool’s real ceiling. The fix in both cases is the same: move to infrastructure where the resources are exclusively yours.
Why Docker Containers Fail with Memory Errors on Shared Hosting
When a container exceeds its memory limit, the Linux kernel’s OOM (out-of-memory) killer terminates it — Docker reports this as exit code 137, and `docker inspect --format='{{.State.OOMKilled}}'` on the container confirms it. On a normal server, you’d raise the container’s memory limit or add RAM. On shared hosting, that option is often unavailable or already capped by the hosting account tier itself — the account has a fixed memory ceiling regardless of what a single container needs, and that ceiling exists precisely because dozens of other accounts share the same physical RAM.
- Check whether a container was actually OOM-killed with `
docker inspect --format='{{.State.OOMKilled}}' <container>` — exit code 137 alone can also mean a manual kill or an external timeout. - Run `
docker stats` to see live memory usage against the container’s limit before it fails. - Check kernel-level OOM events with `
dmesg | grep -i oom` — a host-level OOM kill (not just a container-level one) is a strong sign the shared account’s overall RAM ceiling, not just Docker’s own settings, is the real constraint.
Why Upgrading Your Shared Hosting Plan Doesn’t Fix Slow Load Times
A higher shared-hosting tier typically raises your quota on the shared resource pool — more allowed CPU seconds, a bit more RAM headroom — but the pool itself is still shared with every other account on that physical server. If the server is busy, your “higher-tier” account still competes for the same underlying cores and memory bandwidth as everyone else’s account. This is why a plan upgrade often produces no visible improvement: the bottleneck was never your quota, it was contention for a resource nobody on shared hosting fully controls.
| Shared hosting | VPS | |
|---|---|---|
| Resource allocation | Pooled across all accounts on the server | Allocated to your instance specifically |
| Performance under contention | Can degrade when other accounts are busy | Isolated from other customers’ load |
| Docker support | Often restricted or unavailable | Full support — root access, run any container stack |
| Upgrading fixes contention? | No — raises your quota on the same shared pool | Yes — more dedicated resources, not a bigger slice of a shared one |
For more detailed comparison between Cloud hosting and VPS hosting
Moving Docker Workloads to a VPS
- Estimate your container stack’s real memory needs using `docker stats` on your current setup as a baseline, then add headroom — 30-50% is a reasonable starting buffer.
- Pick a VPS plan sized to that estimate plus growth room, not just your current footprint.
- Install Docker and Docker Compose on the new VPS, and migrate your compose files and volumes over.
- Set explicit memory limits per container (`
mem_limit` in Docker Compose) even on a VPS — this prevents one container from starving the others, the same noisy-neighbor problem shared hosting has, just now fully within your control. - Monitor with `docker stats` after migration to confirm the new limits are appropriate before decommissioning the old shared hosting account.
Why Contabo Is Built for Resource-Heavy Workloads
Contabo’s Core VPS line gives Docker workloads dedicated RAM and CPU allocation from the start — the Cloud VPS 8 plan’s 24 GB RAM at roughly €14/month, for example, is resource capacity that’s genuinely yours, not a quota on a pool shared with other customers. For workloads that have outgrown even a generous VPS, the VDS line adds dedicated physical cores on top, removing the shared-CPU variable entirely.
FAQ: Shared Hosting Resource Limits
Most shared hosting plans either restrict Docker entirely or cap the account’s total memory well below what a multi-container stack needs, since the underlying RAM is shared across every account on the server. The OOM killer terminates the container when it hits that ceiling — raising the container’s own memory limit doesn’t help if the hosting account’s total allocation is the actual constraint.
A shared hosting upgrade usually increases your quota on a resource pool that’s still shared with other accounts on the same server — it doesn’t guarantee you isolated CPU or RAM. If the server is under load from other tenants, your site can stay slow regardless of which tier you’re on. Moving to a VPS, where resources are allocated to your instance specifically, removes that shared-contention variable.
