Troubleshoot Upgrade Assistant
You should run the Upgrade Assistant from the current major's latest minor and patch before upgrading to the next major stack version. You should end up with a list of steps each with a green filled-in checkmark. Failure to do so causes the common upgrade issues.
The Kibana Upgrade Assistant second step "Migrate system indices" might error System indices migration failed. Click "View Migration Details" to show the output of Elasticsearch's Get feature migration information API
IllegalStateException[unable to create new index [X] because it would match composable template [Y]];
- https://discuss.elastic.co/t/issues-upgrading-elasticsearch-from-8-to-9-due-to-old-7-x-indices-and-restricted-kibana-indices/379133/11 https://support.elastic.dev/knowledge/view/e3d44d38
IllegalStateException[unable to create new index [X] because it would match legacy template [Y]];
- Avoiding "match all" index templates https://support.elastic.dev/knowledge/view/1bbb4cc9
- https://github.com/elastic/kibana/issues/119652#issuecomment-979205209
org.elasticsearch.ElasticsearchException: error occurred while reindexing, bulk failures [{"index":".kibana_1-reindexed-for-8","type":"_doc","id":"space_a:visualization:e1d0f010-9ee7-11e7-8711-e7a007dcef99","cause":{"type":"cluster_block_exception","reason":"index [.kibana_1-reindexed-for-8] blocked by: [FORBIDDEN/8/index write (api)];"},"status":403}
https://www.elastic.co/guide/en/elasticsearch/reference/current/fix-watermark-errors.html
- mapper_parsing_exception from legacy template
.security-*https://github.com/elastic/elasticsearch/issues/86801 https://support.elastic.dev/knowledge/view/794038f9 https://support.elastic.dev/knowledge/view/dd79602f https://support.elastic.dev/knowledge/view/295e812f
mapping set to strict, dynamic introduction of [allow_restricted_indices] within [indices] is not allowed
[instance-0000000000] Missing _meta field in mapping [_doc] of index [.security]
instance-0000000000] failed to notify ClusterStateListener
java.lang.IllegalStateException: Cannot read security-version string in index .security
Security index is not on the current version - the native realm will not be operational until the upgrade API is run on the security index
Get disk usage on all nodes below the value specified in cluster.routing.allocation.disk.watermark.low (nodes impacted: [NODE_NAME])
Enterprise Search host(s) and configuration must be removed.
Cannot update mappings in [.ml-config-reindexed-for-8-reindexed-for-9]: system indices can only use mappings from their descriptors, but the mappings in the request [{\"_doc\":{\"_meta\":{\"managed_index_mappings_version\":1,\"version\":\"8.11.0\"},\"properties\":{\"established_model_memory\":{\"type\":\"keyword\"}}}}] did not match those in the descriptor(s)"}