Create Custom Analyzer after index has been created - elasticsearch

Question

I am trying to add a custom analyzer.
curl -XPUT 'http://localhost:9200/my_index' -d '{
"settings" : {
"analysis" : {
"filter" : {
"my_filter" : {
"type" : "word_delimiter",
"type_table": [": => ALPHA", "/ => ALPHA"]
}
},
"analyzer" : {
"my_analyzer" : {
"type" : "custom",
"tokenizer" : "whitespace",
"filter" : ["lowercase", "my_filter"]
}
}
}
}
}'
It works on my local environment when I can recreate the index every time I want, the problem comes when I try to do the same on other environments like qa or prod, where the index has already been created.
{
"error": "IndexAlreadyExistsException[[my_index] already exists]",
"status": 400
}
How can I add my custom analyzer through the HTTP API?

Answer 1

In the documentation I found that to update index settings I can do this:
curl -XPUT 'localhost:9200/my_index/_settings' -d '
{
"index" : {
"number_of_replicas" : 4
}
}'
And to update analyzer settings the documentation says:
"...it is required to close the index first and open it after the changes are made."
So I ended up doing this:
curl -XPOST 'http://localhost:9200/my_index/_close'
curl -XPUT 'http://localhost:9200/my_index' -d '{
"settings" : {
"analysis" : {
"filter" : {
"my_filter" : {
"type" : "word_delimiter",
"type_table": [": => ALPHA", "/ => ALPHA"]
}
},
"analyzer" : {
"my_analyzer" : {
"type" : "custom",
"tokenizer" : "whitespace",
"filter" : ["lowercase", "my_filter"]
}
}
}
}
}'
curl -XPOST 'http://localhost:9200/my_index/_open'
Which fixed everything for me.

Answer 2

For folks using AWS Elastic-search service, closing and opening is not allowed, They need to follow re-indexing as mentioned here.
Basically create a temp index with all mappings of current original index and add/modify those mappings and settings(where analyzers sit), delete original index and create a new index with that name and copy back all mappings and settings from temp index.