Capturing diagnostics

The Elasticsearch Support Diagnostic tool captures a point-in-time snapshot of cluster statistics and most settings. It works against all Elasticsearch versions.

This information can be used to troubleshoot problems with your cluster. For examples of issues that you can troubleshoot using Support Diagnostic tool output, refer to the Elastic blog.

You can generate diagnostic information using this tool before you contact Elastic Support or Elastic Discuss to minimize turnaround time.

Requirements

edit

Java Runtime Environment or Java Development Kit v1.8 or higher

Access the tool

edit

The Support Diagnostic tool is included as a sub-library in some Elastic deployments:

Elastic Cloud Enterprise: Located under Elastic Cloud Enterprise > Deployment > Operations > Prepare Bundle > Elasticsearch.
Elastic Cloud on Kubernetes: Run as eck-diagnostics.

You can also directly download the diagnostics-X.X.X-dist.zip file for the latest Support Diagnostic release from the support-diagnostic repo.

Capture diagnostic information

edit

To capture an Elasticsearch diagnostic:

In a terminal, verify that your network and user permissions are sufficient to connect to your Elasticsearch cluster by polling the cluster’s health.

For example, with the parameters host:localhost, port:9200, and username:elastic, you’d use the following curl request:
```
curl -X GET -k -u elastic -p https://localhost:9200/_cluster/health
```
If you receive a an HTTP 200 OK response, then you can proceed to the next step. If you receive a different response code, then diagnose the issue before proceeding.
Using the same environment parameters, run the diagnostic tool script.

For information about the parameters that you can pass to the tool, refer to the diagnostic parameter reference.

The following command options are recommended:

Unix-based systems
```
sudo ./diagnostics.sh --type local --host localhost --port 9200 -u elastic -p --bypassDiagVerify --ssl --noVerify
```
Windows
```
sudo .\diagnostics.bat --type local --host localhost --port 9200 -u elastic -p --bypassDiagVerify --ssl --noVerify
```
Script execution modes

You can execute the script in three modes:
- local (default, recommended): Polls the Elasticsearch API, gathers operating system info, and captures cluster and GC logs.
- remote: Establishes an ssh session to the applicable target server to pull the same information as local.
- api: Polls the Elasticsearch API. All other data must be collected manually.
When the script has completed, verify that no errors were logged to diagnostic.log. If the log file contains errors, then refer to Diagnose errors in diagnostic.log.
If the script completed without errors, then an archive with the format <diagnostic type>-diagnostics-<DateTimeStamp>.zip is created in the working directory, or an output directory you have specified. You can review or share the diagnostic archive as needed.

Diagnose a non-200 cluster health response

edit

When you poll your cluster health, if you receive any response other than 200 0K, then the diagnostic tool might not work as intended. The following are possible error codes and their resolutions:

HTTP 401 UNAUTHENTICATED: Additional information in the error will usually indicate either that your username:password pair is invalid, or that your .security index is unavailable and you need to setup a temporary file-based realm user with role:superuser to authenticate.
HTTP 403 UNAUTHORIZED: Your username is recognized but has insufficient permissions to run the diagnostic. Either use a different username or elevate the user’s privileges.
HTTP 429 TOO_MANY_REQUESTS (for example, circuit_breaking_exception): Your username authenticated and authorized, but the cluster is under sufficiently high strain that it’s not responding to API calls. These responses are usually intermittent. You can proceed with running the diagnostic, but the diagnostic results might be incomplete.
HTTP 504 BAD_GATEWAY: Your network is experiencing issues reaching the cluster. You might be using a proxy or firewall. Consider running the diagnostic tool from a different location, confirming your port, or using an IP instead of a URL domain.
HTTP 503 SERVICE_UNAVAILABLE (for example, master_not_discovered_exception): Your cluster does not currently have an elected master node, which is required for it to be API-responsive. This might be temporary while the master node rotates. If the issue persists, then investigate the cause before proceeding.

Diagnose errors in `diagnostic.log`

edit

The following are common errors that you might encounter when running the diagnostic tool:

Error: Could not find or load main class com.elastic.support.diagnostics.DiagnosticApp

This indicates that you accidentally downloaded the source code file instead of diagnostics-X.X.X-dist.zip from the releases page.
Could not retrieve the Elasticsearch version due to a system or network error - unable to continue.

This indicates that the diagnostic couldn’t run commands against the cluster. Poll the cluster’s health again, and ensure that you’re using the same parameters when you run the dianostic batch or shell file.
A security_exception that includes is unauthorized for user:

The provided user has insufficient admin permissions to run the diagnostic tool. Use another user, or grant the user role:superuser privileges.

« Troubleshooting an unbalanced cluster Upgrade Elasticsearch »

Capturing diagnostics