cURL error 7: Failed to connect to nextcloud-aio-fulltextsearch port 9200

[mxwi]

Steps to reproduce

1. install AiO (7.x or 8.x does not matter)
2. activate Fulltextsearch
3. take a look at the log

Expected behavior

Fulltextsearch should work

Actual behavior

Fulltextsearch does not work.

Log:

[fulltextsearch_elasticsearch] Fehler: Retry 0: cURL error 7: Failed to connect to nextcloud-aio-fulltextsearch port 9200 after 1 ms: Couldn't connect to server (see https://curl.haxx.se/libcurl/c/libcurl-errors.html) for http://elastic:123@nextcloud-aio-fulltextsearch:9200/nextcloud-aio/_doc/files%3A6179
	von ? von -- um 17.04.2024, 12:33:35

[fulltextsearch] Warnung: platform seems down. we will update index next cron tick
	von ? von -- um 17.04.2024, 12:33:35

DNS-Lookup from nextcloud-aio-nextcloud is successfull:

7b634cc77d8a:/var/www/html# dig nextcloud-aio-fulltextsearch

; <<>> DiG 9.18.24 <<>> nextcloud-aio-fulltextsearch
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 14313
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;nextcloud-aio-fulltextsearch.  IN      A

;; ANSWER SECTION:
nextcloud-aio-fulltextsearch. 600 IN    A       172.23.0.5

;; Query time: 0 msec
;; SERVER: 127.0.0.11#53(127.0.0.11) (UDP)
;; WHEN: Wed Apr 17 12:45:29 CEST 2024
;; MSG SIZE  rcvd: 90

curl from nextcloud-aio-nextcloud is not successfull except you do it full-qualified (with "." at the end)

7b634cc77d8a:/var/www/html# curl http://elastic:123@nextcloud-aio-fulltextsearch:9200
curl: (7) Failed to connect to nextcloud-aio-fulltextsearch port 9200 after 1 ms: Couldn't connect to server
7b634cc77d8a:/var/www/html# curl http://elastic:123@nextcloud-aio-fulltextsearch.:9200
{
  "name" : "139b7250b311",
  "cluster_name" : "nextcloud-aio",
  "cluster_uuid" : "dC26jS4GQE-LrdSyD-BeKg",
  "version" : {
    "number" : "8.13.0",
    "build_flavor" : "default",
    "build_type" : "docker",
    "build_hash" : "09df99393193b2c53d92899662a8b8b3c55b45cd",
    "build_date" : "2024-03-22T03:35:46.757803203Z",
    "build_snapshot" : false,
    "lucene_version" : "9.10.0",
    "minimum_wire_compatibility_version" : "7.17.0",
    "minimum_index_compatibility_version" : "7.0.0"
  },
  "tagline" : "You Know, for Search"
}

so changing the ElasticSearch servlet to ht tp://elastic:c214286684bf78656670aa60a6494ac1d6f846ff83dbe70e@nextcloud-aio-fulltextsearch.:9200 the full text search is working again.
Watch for the dot

Host OS

Nextcloud AIO version

7.x or 8.x does not matter

Other valuable info

[Zoey2936]

see #4440

[mxwi]

duplicate of #4440