Make systemd-tmpfiles optional

[mnasiadka]

Description

Makes systemd-tmpfiles optional (when installing in container images not supplying systemd-tmpfiles)

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[codecov-commenter]

Codecov Report

Merging #3435 (1d36d4b) into main (9cdacda) will not change coverage.
The diff coverage is n/a.

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@@           Coverage Diff           @@
##             main    #3435   +/-   ##
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  Coverage   91.74%   91.74%           
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  Files         172      172           
  Lines        4991     4991           
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  Hits         4579     4579           
  Misses        412      412           

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[peterzhuamazon]

Taking a look......

[peterzhuamazon]

Verify that even if the /var/run/opensearch dir not created by systemd_tmpfiles, the dir will still be create by opensearch.

% sudo rm -rf /var/run/opensearch

% sudo systemctl start opensearch

% ll /var/run/opensearch
total 4
-rw-r--r-- 1 opensearch opensearch 4 May  5 19:58 opensearch.pid

% curl https://localhost:9200 -ku admin:admin
{
  "name" : <>,
  "cluster_name" : "opensearch",
  "cluster_uuid" : "bMDIYmUqQIqFWEiXJotLwA",
  "version" : {
    "distribution" : "opensearch",
    "number" : "2.7.0",
    "build_type" : "rpm",
    "build_hash" : "b7a6e09e492b1e965d827525f7863b366ef0e304",
    "build_date" : "2023-04-27T21:43:23.577631441Z",
    "build_snapshot" : false,
    "lucene_version" : "9.5.0",
    "minimum_wire_compatibility_version" : "7.10.0",
    "minimum_index_compatibility_version" : "7.0.0"
  },
  "tagline" : "The OpenSearch Project: https://opensearch.org/"
}

[peterzhuamazon]

OSD despite having the code to create /var/run/opensearch-dashboards it will still not create pid file there due to exestart not specify that like in OS.

In fact both of them are creating pid file already in /run/<>.

This is probably some old code that is still generating the tmpfiles conf.

In reality no need to redirect pid to /var/run if they already exist in /run.