My project is using very old version(1.2.1) of ES. Recently we started thinking about upgrading it to the latest one. But it is obviously a rough path to go through. We followed path "reindex in place" on ES website, but we met an issue from the beginning:
What we did was installing migration plugin in v1.2.1, and check for nodes health, then some of them are yellow which said "default_index analyzer has been replaced by the name default". Then it is impossible to do the reindex since the flags are not green. We know the latest version has changed this but how to fix this flag and go through next process?
Thanks in advance!