Question 1

How do I use observer_cli to find memory leaks in production?

Accepted Answer

Use the Process panel to list top memory consumers with 'm' key, then inspect suspected processes for details like heap size and messages. Combine with sliding time windows via recon:proc_window to track abnormal growth over intervals.

Question 2

What's the difference between observer_cli and the built-in observer tool?

Accepted Answer

Observer CLI is terminal-based and optimized for production with minimal overhead, while the built-in observer offers a GUI but may not be safe for live nodes. Observer CLI integrates recon for deeper diagnostics but lacks visualizations.

Question 3

Can observer_cli monitor multiple Erlang nodes at once?

Accepted Answer

No, it monitors one node at a time per instance. For multi-node monitoring, you need to run separate observer_cli sessions or script custom solutions, as it doesn't support aggregated views out-of-the-box.

Question 4

How to set up observer_cli for remote node monitoring?

Accepted Answer

Start observer_cli with the target node name and magic cookie, e.g., :observer_cli.start('target@host', 'cookie'). Ensure the observer_cli application is loaded on the target node, and use escript for standalone execution.

Question 5

Is observer_cli suitable for beginners in Erlang/Elixir?

Accepted Answer

Not really—it assumes knowledge of BEAM concepts like reductions, schedulers, and ETS. Beginners might find the CLI output overwhelming without prior experience in system diagnostics or recon usage.

Question 6

Does observer_cli work with Elixir projects or only Erlang?

Accepted Answer

It works with both; add it as a dependency in mix.exs for Elixir or rebar.config for Erlang. The interface is accessible via :observer_cli.start in Elixir shells, with examples provided in the README.

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