Heyho,
so, regards your questions:
# The default root user is named 'admin'
root_username = huhu
root_password_sha2 =
password_secret = ''
are changed values, you said I should remove every personal data 
Here are some logs:
at org.graylog2.plugin.periodical.Periodical.run(Periodical.java:77) [graylog.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) [?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: org.graylog.shaded.elasticsearch7.org.elasticsearch.ElasticsearchStatusException: Elasticsearch exception [type=validation_exception, reason=Validation Failed: 1: this action would add [4] total shards, but this cluster currently has [1000]/[1000] maximum shards open;]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.rest.BytesRestResponse.errorFromXContent(BytesRestResponse.java:187) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.parseEntity(RestHighLevelClient.java:1892) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.parseResponseException(RestHighLevelClient.java:1869) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1626) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1598) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1565) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.IndicesClient.create(IndicesClient.java:145) ~[?:?]
at org.graylog.storage.elasticsearch7.IndicesAdapterES7.lambda$create$3(IndicesAdapterES7.java:153) ~[?:?]
at org.graylog.storage.elasticsearch7.ElasticsearchClient.execute(ElasticsearchClient.java:98) ~[?:?]
... 15 more
Suppressed: org.graylog.shaded.elasticsearch7.org.elasticsearch.client.ResponseException: method [PUT], host [http://127.0.0.1:9200], URI [/seed_0?master_timeout=30s&timeout=30s], status line [HTTP/1.1 400 Bad Request]
{"error":{"root_cause":[{"type":"validation_exception","reason":"Validation Failed: 1: this action would add [4] total shards, but this cluster currently has [1000]/[1000] maximum shards open;"}],"type":"validation_exception","reason":"Validation Failed: 1: this action would add [4] total shards, but$
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestClient.convertResponse(RestClient.java:302) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestClient.performRequest(RestClient.java:272) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestClient.performRequest(RestClient.java:246) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.internalPerformRequest(RestHighLevelClient.java:1613) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.performRequest(RestHighLevelClient.java:1598) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.RestHighLevelClient.performRequestAndParseEntity(RestHighLevelClient.java:1565) ~[?:?]
at org.graylog.shaded.elasticsearch7.org.elasticsearch.client.IndicesClient.create(IndicesClient.java:145) ~[?:?]
at org.graylog.storage.elasticsearch7.IndicesAdapterES7.lambda$create$3(IndicesAdapterES7.java:153) ~[?:?]
at org.graylog.storage.elasticsearch7.ElasticsearchClient.execute(ElasticsearchClient.java:98) ~[?:?]
at org.graylog.storage.elasticsearch7.IndicesAdapterES7.create(IndicesAdapterES7.java:153) ~[?:?]
at org.graylog2.indexer.indices.Indices.create(Indices.java:196) ~[graylog.jar:?]
at org.graylog2.indexer.MongoIndexSet.cycle(MongoIndexSet.java:291) ~[graylog.jar:?]
at org.graylog2.indexer.MongoIndexSet.setUp(MongoIndexSet.java:259) ~[graylog.jar:?]
at org.graylog2.periodical.IndexRotationThread.checkAndRepair(IndexRotationThread.java:138) ~[graylog.jar:?]
at org.graylog2.periodical.IndexRotationThread.lambda$doRun$0(IndexRotationThread.java:76) ~[graylog.jar:?]
at java.lang.Iterable.forEach(Iterable.java:75) [?:?]
at org.graylog2.periodical.IndexRotationThread.doRun(IndexRotationThread.java:73) [graylog.jar:?]
at org.graylog2.plugin.periodical.Periodical.run(Periodical.java:77) [graylog.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) [?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at java.lang.Thread.run(Thread.java:829) [?:?]
2022-04-22T20:40:50.410+02:00 ERROR [IndexRotationThread] Couldn't point deflector to a new index
java.lang.RuntimeException: Could not create new target index <seed_0>.
at org.graylog2.indexer.MongoIndexSet.cycle(MongoIndexSet.java:292) ~[graylog.jar:?]
at org.graylog2.indexer.MongoIndexSet.setUp(MongoIndexSet.java:259) ~[graylog.jar:?]
at org.graylog2.periodical.IndexRotationThread.checkAndRepair(IndexRotationThread.java:138) ~[graylog.jar:?]
at org.graylog2.periodical.IndexRotationThread.lambda$doRun$0(IndexRotationThread.java:76) ~[graylog.jar:?]
at java.lang.Iterable.forEach(Iterable.java:75) [?:?]
at org.graylog2.periodical.IndexRotationThread.doRun(IndexRotationThread.java:73) [graylog.jar:?]
at org.graylog2.plugin.periodical.Periodical.run(Periodical.java:77) [graylog.jar:?]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515) [?:?]
at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:305) [?:?]
at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:305) [?:?]
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) [?:?]
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) [?:?]
at java.lang.Thread.run(Thread.java:829) [?:?]
[2022-04-22T18:40:47.029+0000][126][gc,marking ] GC(68198) Concurrent Mark (173252.039s)
[2022-04-22T18:40:47.029+0000][126][gc,marking ] GC(68198) Concurrent Mark From Roots
[2022-04-22T18:40:47.029+0000][126][gc,task ] GC(68198) Using 1 workers of 1 for marking
[2022-04-22T18:40:47.977+0000][126][gc,marking ] GC(68198) Concurrent Mark From Roots 948.272ms
[2022-04-22T18:40:47.978+0000][126][gc,marking ] GC(68198) Concurrent Preclean
[2022-04-22T18:40:47.980+0000][126][gc,marking ] GC(68198) Concurrent Preclean 2.354ms
[2022-04-22T18:40:47.980+0000][126][gc,marking ] GC(68198) Concurrent Mark (173252.039s, 173252.990s) 950.859ms
[2022-04-22T18:40:47.980+0000][126][gc,start ] GC(68198) Pause Remark
[2022-04-22T18:40:48.019+0000][126][gc ] GC(68198) Pause Remark 560M->560M(1024M) 38.667ms
[2022-04-22T18:40:48.019+0000][126][gc,cpu ] GC(68198) User=0.04s Sys=0.02s Real=0.04s
[2022-04-22T18:40:48.019+0000][126][safepoint ] Safepoint "G1Concurrent", Time since last: 963546896 ns, Reaching safepoint: 251250 ns, At safepoint: 38950441 ns, Total: 39201691 ns
[2022-04-22T18:40:48.020+0000][126][gc,marking ] GC(68198) Concurrent Rebuild Remembered Sets
[2022-04-22T18:40:48.727+0000][126][gc,marking ] GC(68198) Concurrent Rebuild Remembered Sets 707.320ms
[2022-04-22T18:40:48.728+0000][126][gc,start ] GC(68198) Pause Cleanup
[2022-04-22T18:40:48.728+0000][126][gc ] GC(68198) Pause Cleanup 607M->607M(1024M) 0.869ms
[2022-04-22T18:40:48.728+0000][126][gc,cpu ] GC(68198) User=0.00s Sys=0.00s Real=0.00s
[2022-04-22T18:40:48.729+0000][126][safepoint ] Safepoint "G1Concurrent", Time since last: 707671347 ns, Reaching safepoint: 534165 ns, At safepoint: 1046076 ns, Total: 1580241 ns
[2022-04-22T18:40:48.729+0000][126][gc,marking ] GC(68198) Concurrent Cleanup for Next Mark
[2022-04-22T18:40:48.730+0000][126][gc,marking ] GC(68198) Concurrent Cleanup for Next Mark 1.379ms
[2022-04-22T18:40:48.730+0000][126][gc ] GC(68198) Concurrent Cycle 1713.552ms
[2022-04-22T18:40:49.078+0000][126][gc,start ] GC(68199) Pause Young (Concurrent Start) (G1 Humongous Allocation)
[2022-04-22T18:40:49.078+0000][126][gc,task ] GC(68199) Using 2 workers of 2 for evacuation
[2022-04-22T18:40:49.078+0000][126][gc,age ] GC(68199) Desired survivor size 19398656 bytes, new threshold 15 (max threshold 15)
[2022-04-22T18:40:49.092+0000][126][gc,age ] GC(68199) Age table with threshold 15 (max threshold 15)
[2022-04-22T18:40:49.092+0000][126][gc,age ] GC(68199) - age 1: 5292360 bytes, 5292360 total
[2022-04-22T18:40:49.092+0000][126][gc,age ] GC(68199) - age 2: 1678592 bytes, 6970952 total
[2022-04-22T18:40:49.092+0000][126][gc,phases ] GC(68199) Pre Evacuate Collection Set: 0.2ms
[2022-04-22T18:40:49.092+0000][126][gc,phases ] GC(68199) Merge Heap Roots: 0.3ms
[2022-04-22T18:40:49.092+0000][126][gc,phases ] GC(68199) Evacuate Collection Set: 12.1ms
[2022-04-22T18:40:49.092+0000][126][gc,phases ] GC(68199) Post Evacuate Collection Set: 1.0ms
[2022-04-22T18:40:49.092+0000][126][gc,phases ] GC(68199) Other: 0.4ms
[2022-04-22T18:40:49.092+0000][126][gc,heap ] GC(68199) Eden regions: 233->0(290)
[2022-04-22T18:40:49.092+0000][126][gc,heap ] GC(68199) Survivor regions: 3->8(37)
[2022-04-22T18:40:49.092+0000][126][gc,heap ] GC(68199) Old regions: 412->412
[2022-04-22T18:40:49.092+0000][126][gc,heap ] GC(68199) Archive regions: 2->2
[2022-04-22T18:40:49.092+0000][126][gc,heap ] GC(68199) Humongous regions: 16->7
[2022-04-22T18:40:49.092+0000][126][gc,metaspace] GC(68199) Metaspace: 82582K(85680K)->82582K(85680K) NonClass: 73279K(75696K)->73279K(75696K) Class: 9302K(9984K)->9302K(9984K)
[2022-04-22T18:40:49.092+0000][126][gc ] GC(68199) Pause Young (Concurrent Start) (G1 Humongous Allocation) 664M->427M(1024M) 14.168ms
[2022-04-22T18:40:49.092+0000][126][gc,cpu ] GC(68199) User=0.02s Sys=0.00s Real=0.01s
[2022-04-22T18:40:49.092+0000][126][gc ] GC(68200) Concurrent Cycle
[2022-04-22T18:40:49.092+0000][126][gc,marking ] GC(68200) Concurrent Clear Claimed Marks
[2022-04-22T18:40:49.092+0000][126][safepoint ] Safepoint "G1TryInitiateConcMark", Time since last: 349242909 ns, Reaching safepoint: 198241 ns, At safepoint: 14339396 ns, Total: 14537637 ns
[2022-04-22T18:40:49.092+0000][126][gc,marking ] GC(68200) Concurrent Clear Claimed Marks 0.069ms
[2022-04-22T18:40:49.092+0000][126][gc,marking ] GC(68200) Concurrent Scan Root Regions
[2022-04-22T18:40:49.097+0000][126][gc,marking ] GC(68200) Concurrent Scan Root Regions 4.342ms
[2022-04-22T18:40:49.097+0000][126][gc,marking ] GC(68200) Concurrent Mark (173254.107s)
[2022-04-22T18:40:49.097+0000][126][gc,marking ] GC(68200) Concurrent Mark From Roots
[2022-04-22T18:40:49.097+0000][126][gc,task ] GC(68200) Using 1 workers of 1 for marking
[2022-04-22T18:40:50.105+0000][126][gc,marking ] GC(68200) Concurrent Mark From Roots 1007.836ms
[2022-04-22T18:40:50.105+0000][126][gc,marking ] GC(68200) Concurrent Preclean
[2022-04-22T18:40:50.107+0000][126][gc,marking ] GC(68200) Concurrent Preclean 2.055ms
[2022-04-22T18:40:50.107+0000][126][gc,marking ] GC(68200) Concurrent Mark (173254.107s, 173255.117s) 1010.017ms
[2022-04-22T18:40:50.107+0000][126][gc,start ] GC(68200) Pause Remark
[2022-04-22T18:40:50.133+0000][126][gc ] GC(68200) Pause Remark 521M->519M(1024M) 26.026ms
[2022-04-22T18:40:50.133+0000][126][gc,cpu ] GC(68200) User=0.04s Sys=0.01s Real=0.03s
[2022-04-22T18:40:50.133+0000][126][safepoint ] Safepoint "G1Concurrent", Time since last: 1014570315 ns, Reaching safepoint: 215059 ns, At safepoint: 26221867 ns, Total: 26436926 ns
[2022-04-22T18:40:50.133+0000][126][gc,marking ] GC(68200) Concurrent Rebuild Remembered Sets
[2022-04-22T18:40:50.898+0000][126][gc,marking ] GC(68200) Concurrent Rebuild Remembered Sets 764.420ms
[2022-04-22T18:40:50.898+0000][126][gc,start ] GC(68200) Pause Cleanup
[2022-04-22T18:40:50.899+0000][126][gc ] GC(68200) Pause Cleanup 626M->626M(1024M) 0.743ms
[2022-04-22T18:40:50.899+0000][126][gc,cpu ] GC(68200) User=0.00s Sys=0.00s Real=0.00s
[2022-04-22T18:40:50.899+0000][126][safepoint ] Safepoint "G1Concurrent", Time since last: 764742546 ns, Reaching safepoint: 266387 ns, At safepoint: 879465 ns, Total: 1145852 ns
[2022-04-22T18:40:50.899+0000][126][gc,marking ] GC(68200) Concurrent Cleanup for Next Mark
I create a index Set with the rotation config of delete index after 365 days and no, it should be then a standalone index, so I can later search for that in the log search