Unexpected failure during TASK SOURCE – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.1-8.9

Briefly, this error occurs when Elasticsearch encounters an unexpected issue while executing a task. This could be due to various reasons such as insufficient resources, network issues, or a bug in the Elasticsearch code. To resolve this issue, you can try increasing the resources allocated to Elasticsearch, checking the network connectivity, or updating Elasticsearch to the latest version. Additionally, you can also check the Elasticsearch logs for more detailed information about the error, which can help in identifying the root cause and fixing it.

This guide will help you check for common problems that cause the log ” unexpected failure during [” + TASK_SOURCE + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin, license.

Log Context

Log “unexpected failure during [” + TASK_SOURCE + “]” classname is StartupSelfGeneratedLicenseTask.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        return ClusterState.builder(currentState).metadata(mdBuilder).build();

    public void onFailure(@Nullable Exception e) {
        logger.error((Supplier>) () -> "unexpected failure during [" + TASK_SOURCE + "]"; e);

    private ClusterState extendBasic(ClusterState currentState; LicensesMetadata currentLicenseMetadata) {
        License license = currentLicenseMetadata.getLicense();
        Metadata.Builder mdBuilder = Metadata.builder(currentState.metadata());