Copying reaper jar – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.4-8.9

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Briefly, this error occurs when Elasticsearch tries to copy the reaper jar file, which is used for cleaning up old index files, but encounters an issue. This could be due to insufficient permissions, lack of disk space, or a network error. To resolve this, you can check and adjust the file permissions, ensure there is enough disk space, or troubleshoot network connectivity. Additionally, you can also verify the integrity of the reaper jar file, as it might be corrupted.

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This guide will help you check for common problems that cause the log ” Copying reaper.jar… ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “Copying reaper.jar…” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            try (
                OutputStream out = Files.newOutputStream(jarPath);
                InputStream jarInput = this.getClass().getResourceAsStream("/META-INF/reaper.jar");
            ) {
      "Copying reaper.jar...");
            } catch (IOException e) {
                throw new UncheckedIOException(e);


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