Aliased Indexes

You can set up FOSElasticaBundle to use aliases for indexes which allows you to run an index population without resetting the index currently being used by the application.

Note: When you're using an alias, resetting an individual index will still cause a reset for that index.

To configure FOSElasticaBundle to use aliases for an index, set the use_alias option to true.

fos_elastica:
    indexes:
        app:
            use_alias: true

The process for setting up aliases on an existing application is slightly more complicated because the bundle is not able to set an alias as the same name as an index. You have 2 options on how to handle this:

1. Option with downtime : Delete the index from Elasticsearch. This option will make searching unavailable in your application until a population has completed itself, and an alias is created.

$ curl -XDELETE 'http://localhost:9200/app/'

2. Option without downtime : Change the index_name parameter for your index to something new, and manually alias the current index to the new index_name, which will then be replaced when you run a repopulate.

# before actions
curl -XGET 'http://localhost:9200/_alias/?pretty'
{
  "app" : {
    "aliases" : { }
  }
}

# create alias to switch after with no downtime
$ curl -XPOST 'http://localhost:9200/_aliases' -H 'Content-Type: application/json'  -d '
{
    "actions" : [
        { "add" : { "index" : "app", "alias" : "app_prod" } }
    ]
}'

#check alias is ok
curl -XGET 'http://localhost:9200/_alias/?pretty'
{
  "app" : {
    "aliases" : { "app_prod" : { } }
  }
}

#index name is alias name
fos_elastica:
    indexes:
        app:
            use_alias: true
            index_name: app_prod

clear caches etc, now fos use alias instead of index

bin/console -eprod 'fos:elastica:populate'

in other cli in // check indexes during populate process

curl -XGET 'http://localhost:9200/_alias/?pretty'
{
  "app" : {
    "aliases" : {
      "app_prod" : { }
    }
  },
  "app_prod_2019-05-28-153852" : {
    "aliases" : { }
  }
}

when 'fos:elastica:populate' command finish

curl -XGET 'http://localhost:9200/_alias/?pretty'
{
  "app_prod_2019-05-28-153852" : {
    "aliases" : {
        "app_prod" : { }
    }
  }
}