Solr

Search. Needs ZooKeeper, which is added automatically. A stack runs one search engine — Solr or Meilisearch — so naming the other replaces it, and what is lost is an index that reindexes.

Solr requires a login. Your application finds it at SOLR_HOST, port 8983, and signs in as SOLR_USER with SOLR_PASSWORD. Both are in its environment. The password is made for each environment and never changes. A request without it is refused, so configure your client with it. For Drupal, see the snippet.

Its heap is sized from your machine — half of a search machine it has to itself, a share of your plan when it sits beside your site. Set SOLR_HEAP lower if you want; a higher value is lowered to that share. The extraction, language detection, learning-to-rank and analysis-extras modules are loaded unless you set SOLR_MODULES to something else.

#Versions

A deprecated version still runs and is still what some sites are on. It is listed so you can move before it goes, rather than finding out on the morning a build stops resolving it.

Pin the version, not the build: name 10.0 and the platform matches it to the current build, so a security rebuild reaches you without anybody editing a repository.

The version you name is the one your environment runs from the next deploy. This service keeps data, and not every version can read another's — before you change it, read Changing a service's version.

#What you can change

In vallic.yaml — what each one does is on Service settings:

services:
  - solr:
      version: '10.0'
      environment:
        SOLR_HEAP: …
        SOLR_MODULES: …

Anything not on this list refuses the deploy, naming the variable — rather than being accepted and quietly ignored.