Skipping unknown custom object with type – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters an unknown custom object type during deserialization. This could be due to a missing plugin or a version mismatch between nodes. To resolve this issue, ensure that all nodes in the cluster are running the same version of Elasticsearch and that all necessary plugins are installed. If the error persists, check your data for any inconsistencies or corruption.

This guide will help you check for common problems that cause the log ” Skipping unknown custom object with type {} ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: metadata, cluster.

Log Context

Log “Skipping unknown custom object with type {}” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                    } else {
                        try {
                            Custom custom = parser.namedObject(Custom.class; currentFieldName; null);
                            builder.putCustom(custom.getWriteableName(); custom);
                        } catch (NamedObjectNotFoundException ex) {
                            logger.warn("Skipping unknown custom object with type {}"; currentFieldName);
                } else if (token.isValue()) {
                    if ("version".equals(currentFieldName)) {