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How to check which service is failing in microservices

Check which microservice is failing by setting up your services, watching ports and logs, and using a tool that shows each service's status and errors.

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Start from one failing request, follow its path through each service in order, and check each service's status, port and errors. Test each service on its own as well. The first real error on that path usually points to the service that is failing.

OptionWhat it doesCost
DevWebUIStarts, stops and restarts local dev servers from one dashboard, and shows each one's status, CPU, memory and logs. [1]Free, and core features need no account. [1]
Terminal commands and scriptsNot covered by a source here. Check how it shows status and errors for each service.not published
Development environment run configurationsNot covered by a source here. Check how it shows status and errors for each service, and how it handles ports.not published

What you need before you start

Before you check which service is failing, make sure every service in the system has a clear name, a known start command and a known port. Keep a written list of which services call which others, so a failure in one can be traced to the services that depend on it. Confirm that each service's dependencies are installed and that its environment settings are in place, because a missing setting can look like a failure somewhere else. Know where each service writes its logs and whether it prints errors to the terminal, to a file, or to both. Decide which services must run together for a request to succeed, such as an API gateway, an authentication service, a database and a message queue. With this list ready, it is easier to tell a service that is down from one that is only slow or misconfigured.

Step by step

  1. Write down the request path. Pick one request that fails and list every service it passes through, in order.
  1. Check which services are running. Confirm that each service on the path is up, and note any that have stopped or restarted.
  1. Check the ports. Confirm each service is listening on the port in your list, and look for a second process holding the same port.
  1. Read the logs from the start of the path. Begin with the service closest to the request and move along the path, since the first real error often explains the rest.
  1. Look for repeated errors. Repeated messages can point to a retry loop or to a dependency that keeps failing.
  1. Test each service on its own. Send a direct request to each service, bypassing the others, to see which one fails alone.
  1. Check dependencies. A service may be healthy but waiting for a database, cache or queue that is down.
  1. Record the cause and the fix. Note which service failed, why it failed and what changed, so the next check starts faster.

Tools that can do it

DevWebUI is made by the team that publishes this site. DevWebUI lets you start, stop and restart your local dev servers from one dashboard, and see each one's status, CPU, memory and logs. [1] Errors are collected into one log that merges repeats and is kept across restarts, and each file:line link opens in your editor. [1] When a port is already taken, DevWebUI shows which process holds it and can free the port if you ask. [1] It also lets you set threshold alert rules and see a history of the alerts that fired. [1]

Terminal commands and scripts are other options, as are the run configurations inside development environments. Check how each one shows status, errors and ports for every service before you choose.

Common mistakes to avoid

A common mistake is checking only the service that raised the alarm and skipping the services it depends on. The failing service may be fine while a database or queue it waits on has stopped. Reading logs one service at a time, with no shared timeline, makes it hard to see which error came first. Restarting every service at once hides the original failure, because the first one to break is no longer visible. Changing several settings before testing makes it unclear which change helped or caused the problem. Write down each change and test after it, so the cause stays clear.

Frequently asked questions

How can microservice developers check which service is failing?

Start from one failing request and follow its path through each service in order. Check that each service is running, listening on its expected port and writing errors to its log. The first real error along that path usually points to the failing service. Testing each service on its own with a direct request shows whether it fails alone or only when another service is down. Recording what you found makes the next check faster.

Does DevWebUI show which microservice is failing?

DevWebUI shows each local server's status, CPU, memory and logs in one dashboard, so a stopped service is visible next to the others. [1] It collects errors into one log that merges repeats and is kept across restarts, and each file:line link opens in your editor. [1] Check that your full set of services can run under it before relying on it for every check.

Can DevWebUI alert you when a service fails?

DevWebUI lets you set threshold alert rules and see a history of the alerts that fired. [1] A threshold rule fires when a measured value crosses a limit you choose. Pick the limits that matter for your services, and review the alert history after each failure to see what changed first.

Is DevWebUI free for microservice developers?

DevWebUI is free, and its core features need no account. [1] It is open source under the MIT License. [1] A prebuilt Windows app is available, and on other systems you run it from source with Bun, a tool for running JavaScript. [1] Check that your operating system is covered before you choose it.

What should microservice developers check before choosing a tool?

Check how the tool shows the status of each service, where it collects errors and how it handles a port that is already in use. Confirm that it works with your operating system and whether one log covers every service in your system. Ask how it behaves when a service fails during a restart. These answers decide whether the tool fits your setup, so compare them before you choose.

DevWebUI is free, and its core features need no account. [1]

Try DevWebUI

Sources

  1. DevWebUI's own description of itself (the product of this site's publisher)

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