Stop Watching Progress Bars: Optimizing CI/CD Pipelines with Docker 1.7 and SSDs
There is nothing—and I mean nothing—more demoralizing for a development team than staring at a Jenkins console output crawling line by line. You push a commit, and then you wait. You grab coffee. You wait. You debate the merits of spaces vs. tabs. You wait.
If your build pipeline takes 20 minutes to deploy a simple hotfix, you don't have a CI/CD pipeline; you have a queue management problem. In the last year, the shift toward containerization has been aggressive, but it has exposed a glaring weakness in most legacy infrastructure: Storage I/O.
Here is the reality of the situation in mid-2015: The bottleneck isn't your CPU clock speed. It's the disk. And if you are still running your build agents on spinning rust or over-provisioned cloud storage, you are burning developer hours.
The Hidden Killer: IO Wait on Build Agents
Let's look at a typical modern workflow using Docker (specifically the new 1.7 release). A standard build process involves:
- Pulling base images (Write heavy).
npm installormaven build(Read/Write explosion of small files).- Creating intermediate containers (Write heavy).
- Committing the final layer (Write heavy).
I recently audited a pipeline for a client in Oslo running a Magento stack. Their build times were pushing 45 minutes. We ran iostat -x 1 during a build and saw %util hitting 100% on the disk while the CPU sat idle at 15%. They were hosting on a budget provider with standard SATA storage. The drives simply couldn't handle the random write patterns of a concurrent Docker build.
Pro Tip: When using Jenkins with Docker, avoid the overhead of "Docker-in-Docker" (dind) if you can help it. It’s often cleaner and faster to mount the host's Docker socket, though this comes with security implications you need to manage.
The Hardware Fix: Why SSDs Are Non-Negotiable
We migrated that same Magento pipeline to a CoolVDS instance backed by Enterprise SSDs. We didn't touch the code. We didn't optimize the Dockerfile (yet). Build time dropped from 45 minutes to 8 minutes.
Why? Because compiling code and building container layers requires high IOPS (Input/Output Operations Per Second). Traditional HDDs might give you 100 IOPS. A solid SSD array pushes tens of thousands. When you have ten developers pushing commits simultaneously, that queue depth explodes.
At CoolVDS, we don't upsell SSDs as a "premium" tier for this exact reason. In 2015, if your storage isn't solid-state, it's obsolete for DevOps.
Configuration Tune-up: Utilizing Docker 1.7
Hardware solves the grunt work, but configuration solves the efficiency. With the release of Docker 1.7 last month, we have better controls. If you are running your own registry or aggressive caching, you need to ensure your cleanup scripts are robust to prevent inode exhaustion.
Here is a snippet for a robust cleanup cron job I run on build nodes to keep the SSDs clean without nuking active containers:
#!/bin/bash
# Clean up exited containers older than an hour
docker ps -a | grep 'Exited' | awk '{print $1}' | xargs --no-run-if-empty docker rm
# Clean up dangling images (untagged)
docker images -q --filter "dangling=true" | xargs --no-run-if-empty docker rmi
Data Sovereignty and Latency: The Norway Advantage
Beyond the disk speed, we have to talk about physics and the law. If your dev team is in Trondheim or Oslo, why are your build artifacts traveling to a data center in Frankfurt or Virginia?
- Latency: CoolVDS peers directly at NIX (Norwegian Internet Exchange). pushing a 500MB Docker image to a local registry in Oslo takes seconds. Pushing it across the Atlantic takes... longer.
- Compliance: With the ongoing scrutiny on Safe Harbor and the strict enforcement by Datatilsynet, keeping your source code and customer data (often used in staging DB dumps) on Norwegian soil is the safest play for the pragmatic CTO.
| Feature | Generic Cloud VPS | CoolVDS Norway |
|---|---|---|
| Storage | Network Attached (High Latency) | Local Enterprise SSD |
| Virtualization | Often Container-based (Noisy Neighbors) | KVM (Kernel-based Virtual Machine) |
| Location | Unknown / Europe General | Oslo, Norway (NIX Peering) |
The Verdict
You can spend weeks optimizing your Makefile, or you can solve the root cause. A CI/CD pipeline is only as fast as the disk it writes to. Don't let IO wait steal your team's productivity.
Ready to cut your build times in half? Deploy a high-performance KVM instance on CoolVDS today and experience the difference raw I/O power makes.