Observability and Logs

📄️ Kernel Logs Viewer

When a kernel won't start, an init script fails, or a Spark job behaves unexpectedly, the kernel logs are usually where the answer lives. The kernel logs viewer is a built-in modal that streams those logs in your browser — no kubectl, no shell, no admin help required. Open it from a toolbar button next to the Spark UI button and you're looking at the live log stream for the kernel attached to this notebook.

📄️ Spark UI Access

Every notebook toolbar has a Spark icon that opens the standard Spark Applications UI in a new browser tab. The icon is disabled until your kernel's Spark session is ready — once Spark has started, the icon becomes clickable and takes you straight to the live UI for the application your notebook is running.

📄️ Spark History Server

The Spark History Server is the standard upstream UI for Spark applications that have already completed. Where the Spark UI in Spark UI Access how's the application currently running on your kernel, the History Server is where you go after the kernel has gone — to inspect a past run, compare two runs, or verify a process result.

📄️ Init Script Logs & Troubleshooting

The kernel logs viewer in Kernel Logs Viewer is the right starting point for most troubleshooting — it streams the live logs in your browser and is enough to diagnose the majority of init-script and dependency failures. This article is what you reach for when the viewer doesn't have what you need: it lays out every log file the kernel writes, gives you small snippets to verify a JAR or Python package landed where you expected, and lists the most common failure modes with their fix.