Alibaba Cloud Full Stack (7): SLS, CloudMonitor, and Observability

Mon, 04 May 2026 09:00:00 +0000

The worst production outage I ever caused took three hours to diagnose. A Node.js service was returning 502s intermittently — maybe 5% of requests — and I had nothing. No centralized logs (each ECS instance had its own /var/log/ and I was SSH-ing into them one at a time). No metrics dashboards (I was running top and df -h in terminals). No tracing (I was adding console.log timestamps to try to figure out which downstream call was hanging). Three hours later, I found the issue: a connection pool to RDS was exhausting under load because a forgotten cron job was holding connections open. The fix was two lines of code. The diagnosis took three hours of misery because I had zero observability.

Docker and Containers (6): Debugging and Logging — When Things Go Wrong Inside a Box

Wed, 21 Jun 2023 09:00:00 +0000

A container that works is invisible. A container that doesn’t work is a black box. The entire point of containerization is isolation — but that same isolation makes debugging harder. You can’t just ssh into a container or browse its filesystem from the host. Docker provides a specific set of tools for inspecting, diagnosing, and understanding what happens inside running (and crashed) containers.

Reading Container Logs#

Logs are your first line of investigation. Docker captures everything a container writes to stdout and stderr.

Observability on Chen Kai Blog

Alibaba Cloud Full Stack (7): SLS, CloudMonitor, and Observability

Docker and Containers (6): Debugging and Logging — When Things Go Wrong Inside a Box

Reading Container Logs#