Error log: FATAL Error: Request Timeout” – The unresponsive dashboard

Error Log: This error doesn’t appear in your OpenSearch logs. It appears in your OpenSearch Dashboards logs (often in stdout or a opensearch_dashboards.log file).

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[error][data][opensearch] 
  Error: Request Timeout after 30000ms
  at /usr/share/opensearch-dashboards/node_modules/opensearch-js/lib/transport.js:...?

Or you might see a high-level error on startup:

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[fatal][root] 
  Error: [config validation of [opensearch].requestTimeout]: 
  expected value of type [number] but got [string]

Why… is this happening? The Request Timeout after 30000ms error means the OpenSearch Dashboards server sent a request to your OpenSearch cluster (e.g., to fetch mappings, run a query, or check cluster health) and did not get a response within the default 30-second timeout.

This is almost never a problem with Dashboards itself. It’s a symptom that your OpenSearch cluster is unreachable, down, or under extreme load.

Common causes:

1. Cluster is down: The OpenSearch nodes specified in your opensearch_dashboards.yml (opensearch.hosts) are not running.
2. Network/firewall issue: A firewall is blocking the Dashboards server from reaching the OpenSearch cluster on port 9200.
3. SSL misconfiguration: Dashboards is trying to connect via HTTP to an HTTPS-enabled cluster (or vice-versa), or it doesn’t trust the cluster’s self-signed certificates.
4. Cluster under extreme load: The cluster is so overloaded (e.g., from a query that triggered a circuit breaker or a long garbage collection) that it can’t even respond to the simple request from Dashboards within 30 seconds.

Best Practice:

1. Check opensearch.hosts: Open your opensearch_dashboards.yml and double-check the opensearch.hosts setting. Is the URL correct? Is it http or https?

2. Test connectivity from the dashboards server: Log in to the server running OpenSearch Dashboards and use curl to try and reach your cluster from there. This bypasses Dashboards and tests the raw network connection.
Bash

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# From the Dashboards server machine:
curl -k "https://your-opensearch-node:9200"

3. If this curl command hangs or fails, Dashboards has no chance. You have a network, firewall, or cluster-down problem.

4. Check Dashboards SSL config: If your cluster uses HTTPS with self-signed certs, you must configure opensearch.ssl.verificationMode: "none" (insecure, for testing) or (better) opensearch.ssl.certificateAuthorities: ["/path/to/root-ca.pem"] in your opensearch_dashboards.yml.

5. Check Cluster Health: If curl works, check your cluster’s health (_cluster/health). Is it red? Are nodes overloaded or in a long GC?

What else can I do? If curl from the Dashboards server works, but the Dashboards UI still times out, you might have a more complex issue. Ask the OpenSearch community, and be sure to share your opensearch_dashboards.yml (with passwords redacted). For direct support, contact us in The OpenSearch Slack Channel in #General.