Interesting Links

Links EOE:

I am adding some of my own:
Tuning beats:
https://www.elastic.co/blog/how-to-tune-elastic-beats-performance-a-practical-example-with-batch-size-worker-count-and-more
Tuning logstash:
https://www.elastic.co/guide/en/logstash/current/performance-tuning.html
Tuning Es for index:
https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-for-indexing-speed.html
Tuning Es for search:
https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-for-search-speed.html
Tuning Es for disk usage:
https://www.elastic.co/guide/en/elasticsearch/reference/current/tune-for-disk-usage.html

Some infrastructure recommendation
https://www.elastic.co/guide/en/cloud-enterprise/2.4/ece-planning-hw.html

Network recommendations
https://www.elastic.co/guide/en/cloud-enterprise/current/ece-prereqs-networking.html#ece-hosts_in_multiple_data_centers

About recommendations  of hardware you can create a trial account in here and see the default values:
https://cloud.elastic.co

Cluster sizing webinar 
https://www.elastic.co/elasticon/conf/2016/sf/quantitative-cluster-sizing
We also wrote a blog with an in-depth description of the heap behavior here: 
https://www.elastic.co/blog/a-heap-of-trouble
Shard information 
https://www.elastic.co/blog/how-many-shards-should-i-have-in-my-elasticsearch-cluster and https://www.elastic.co/blog/every-shard-deserves-a-home
Videos and webinars 
https://www.elastic.co/videos/ as well as Elastic{ON} conference talks https://www.elastic.co/elasticon/videos
Tool used by our support that gives you a report about the nodes (you run in each node and see in a html format a lot of informations)
Support diagnostic - https://github.com/elastic/support-diagnostics

https://www.elastic.co/guide/en/logstash/current/monitoring-internal-collection-legacy.html#logstash-monitoring-collectors-legacy
https://www.elastic.co/guide/en/logstash/current/configuring-logstash.html

http://ec2-54-93-80-0.eu-central-1.compute.amazonaws.com/instructions/index.html
https://discuss.elastic.co/t/elasticsearch-randomly-switched-initial-master-node/234790/3
https://discuss.elastic.co/t/how-to-use-document-id-to-avoid-duplication-of-logs/234644
https://handlebarsjs.com/guide/expressions.html
https://play.golang.org/p/uAd5XHxscu
https://search.maven.org/search?q=g:co.elastic.apm%20AND%20a:elastic-apm-agent
https://www.confluent.io/blog/exactly-once-semantics-are-possible-heres-how-apache-kafka-does-it/
https://www.elastic.co/blog/advanced-tuning-finding-and-fixing-slow-elasticsearch-queries
https://www.elastic.co/blog/a-profile-a-day-keeps-the-doctor-away-the-elasticsearch-search-profiler
https://www.elastic.co/blog/how-many-shards-should-i-have-in-my-elasticsearch-cluster
https://www.elastic.co/blog/introducing-beats-central-management-in-the-elastic-stack
https://www.elastic.co/blog/logstash-lessons-handling-duplicates
https://www.elastic.co/blog/lucenes-handling-of-deleted-documents
https://www.elastic.co/blog/seven-tips-for-better-elasticsearch-benchmarks
https://www.elastic.co/blog/structured-logging-filebeat
https://www.elastic.co/blog/using-painless-kibana-scripted-fields
https://www.elastic.co/elasticon/conf/2016/sf/quantitative-cluster-sizing
https://www.elastic.co/guide/en/apm/agent/dotnet/current/index.html
https://www.elastic.co/guide/en/apm/agent/dotnet/current/public-api.html
https://www.elastic.co/guide/en/apm/agent/index.html
https://www.elastic.co/guide/en/apm/agent/java/1.x/config-reporter.html#config-max-queue-size
https://www.elastic.co/guide/en/apm/agent/java/current/supported-technologies-details.html
https://www.elastic.co/guide/en/apm/agent/python/5.x/tuning-and-overhead.html#tuning-queue
https://www.elastic.co/guide/en/apm/server/current/common-problems.html#server-es-down
https://www.elastic.co/guide/en/apm/server/current/configuring-output.html
https://www.elastic.co/guide/en/apm/server/current/exploring-es-data.html
https://www.elastic.co/guide/en/beats/filebeat/current/configuration-filebeat-options.html
https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-module-misp.html
https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-modules.html
https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-module-system.html
https://www.elastic.co/guide/en/beats/filebeat/current/file-log-rotation.html
https://www.elastic.co/guide/en/beats/filebeat/current/inode-reuse-issue.html
https://www.elastic.co/guide/en/beats/filebeat/current/load-kibana-dashboards.html
https://www.elastic.co/guide/en/beats/filebeat/master/dissect.html
https://www.elastic.co/guide/en/beats/filebeat/master/how-central-managment-works.html
https://www.elastic.co/guide/en/beats/heartbeat/current/configuration-heartbeat-options.html
https://www.elastic.co/guide/en/beats/heartbeat/current/configuration-heartbeat-options.html#configuration-heartbeat-options
https://www.elastic.co/guide/en/beats/heartbeat/current/monitor-http-options.html#monitor-http-check
https://www.elastic.co/guide/en/beats/libbeat/current/community-beats.html
https://www.elastic.co/guide/en/beats/metricbeat/current/metricbeat-modules.html
https://www.elastic.co/guide/en/beats/winlogbeat/current/load-kibana-dashboards.html
https://www.elastic.co/guide/en/ecs/current/ecs-conventions.html
https://www.elastic.co/guide/en/ecs/current/ecs-guidelines.html
https://www.elastic.co/guide/en/elasticsearch/guide/2.x/docvalues.html
https://www.elastic.co/guide/en/elasticsearch/painless/7.7/painless-guide.html
https://www.elastic.co/guide/en/elasticsearch/plugins/7.7/mapper-size-usage.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.2/cat-count.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.2/docs-index_.html#operation-type
https://www.elastic.co/guide/en/elasticsearch/reference/7.4/search-settings.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.7/doc-values.html
https://www.elastic.co/guide/en/elasticsearch/reference/7.x/enrich-processor.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-update.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/general-recommendations.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-types.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/pipeline-processor.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl.html
https://www.elastic.co/guide/en/elasticsearch/reference/current/search-settings.html
https://www.elastic.co/guide/en/elasticsearch/reference/master/index-modules.html#dynamic-index-settings
https://www.elastic.co/guide/en/logstash/current/persistent-queues.html
https://www.elastic.co/guide/en/logstash/current/plugins-outputs-elasticsearch.html#plugins-outputs-elasticsearch-action
https://www.elastic.co/training/structuring-log-data
https://www.elastic.co/webinars/using-rally-to-get-your-elasticsearch-cluster-size-right
https://www.youtube.com/watch?v=CNR-4kZ6v_E
https://www.youtube.com/watch?v=CvorsH3x7Z8
https://www.youtube.com/watch?v=xkluflzhpAw&t=9s