Just patched kibana as the last component after patching hole cluster from 7.4.0 to 7.4.1 and find these kibana warnings when launched:
{"type":"log","@timestamp":"2019-10-26T07:31:24Z","tags":["warning","plugins","security","config"],"pid":19245,"message":"Generating a random key for xpack.security.encryptionKey. To prevent sessions from being invalidated on restart, please set xpack.security.encryptionKey in kibana.yml"}
{"type":"log","@timestamp":"2019-10-26T07:31:45Z","tags":["plugin","warning"],"pid":19245,"path":"/opt/kibana/src/legacy/core_plugins/markdown_vis","message":"Skipping non-plugin directory at /opt/kibana/src/legacy/core_plugins/markdown_vis"}
{"type":"log","@timestamp":"2019-10-26T07:31:45Z","tags":["plugin","warning"],"pid":19245,"path":"/opt/kibana/src/legacy/core_plugins/metric_vis","message":"Skipping non-plugin directory at /opt/kibana/src/legacy/core_plugins/metric_vis"}
{"type":"log","@timestamp":"2019-10-26T07:31:45Z","tags":["plugin","warning"],"pid":19245,"path":"/opt/kibana/src/legacy/core_plugins/table_vis","message":"Skipping non-plugin directory at /opt/kibana/src/legacy/core_plugins/table_vis"}
{"type":"log","@timestamp":"2019-10-26T07:31:45Z","tags":["plugin","warning"],"pid":19245,"path":"/opt/kibana/src/legacy/core_plugins/tagcloud","message":"Skipping non-plugin directory at /opt/kibana/src/legacy/core_plugins/tagcloud"}
{"type":"log","@timestamp":"2019-10-26T07:31:45Z","tags":["plugin","warning"],"pid":19245,"path":"/opt/kibana/src/legacy/core_plugins/vega","message":"Skipping non-plugin directory at /opt/kibana/src/legacy/core_plugins/vega"}
{"type":"log","@timestamp":"2019-10-26T07:31:47Z","tags":["warning","encrypted_saved_objects"],"pid":19245,"message":"Generating a random key for xpack.encrypted_saved_objects.encryptionKey. To be able to decrypt encrypted saved objects attributes after restart, please set xpack.encrypted_saved_objects.encryptionKey in kibana.yml"}
{"type":"log","@timestamp":"2019-10-26T07:31:47Z","tags":["reporting","browser-driver","warning"],"pid":19245,"message":"Enabling the Chromium sandbox provides an additional layer of protection."}
{"type":"log","@timestamp":"2019-10-26T07:31:48Z","tags":["warning"],"pid":19245,"kibanaVersion":"7.4.1","nodes":[{"version":"7.4.0","http":{"publish_address":"grafana.nms.mail.dk/62.243.41.180:9200"},"ip":"62.243.41.180"}],"message":"You're running Kibana 7.4.1 with some different versions of Elasticsearch. Update Kibana or Elasticsearch to the same version to prevent compatibility issues: v7.4.0 @ grafana.nms.mail.dk/62.243.41.180:9200 (62.243.41.180)"}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["reporting","warning"],"pid":19245,"message":"Generating a random key for xpack.reporting.encryptionKey. To prevent pending reports from failing on restart, please set xpack.reporting.encryptionKey in kibana.yml"}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["reporting","warning"],"pid":19245,"message":"The Reporting plugin encountered issues launching Chromium in a self-test. You may have trouble generating reports: [Error: Failed to launch chrome!\n/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version `GLIBC_2.14' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)\n/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version `GLIBC_2.15' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)\n/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version `GLIBC_2.16' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)\n\n\nTROUBLESHOOTING: https://github.com/GoogleChrome/puppeteer/blob/master/docs/troubleshooting.md\n]"}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["reporting","warning"],"pid":19245,"message":"See Chromium's log output at "/var/lib/kibana/headless_shell-linux/chrome_debug.log""}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["reporting","warning"],"pid":19245,"message":"Reporting plugin self-check failed. Please check the Kibana Reporting settings. Error: Could not close browser client handle!"}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["warning","telemetry"],"pid":19245,"message":"Error scheduling task, received [task:oss_telemetry-vis_telemetry]: version conflict, document already exists (current version [17]): [version_conflict_engine_exception] [task:oss_telemetry-vis_telemetry]: version conflict, document already exists (current version [17]), with { index_uuid="CorSIlscTN6pEFXWYLTAlg" & shard="0" & index=".kibana_task_manager_2" }"}
{"type":"log","@timestamp":"2019-10-26T07:31:49Z","tags":["warning","maps"],"pid":19245,"message":"Error scheduling telemetry task, received [task:Maps-maps_telemetry]: version conflict, document already exists (current version [17]): [version_conflict_engine_exception] [task:Maps-maps_telemetry]: version conflict, document already exists (current version [17]), with { index_uuid="CorSIlscTN6pEFXWYLTAlg" & shard="0" & index=".kibana_task_manager_2" }"}
Wondering how to resolve the telemetry version conflict and if it's an issue going forward (patching in future)?
Wouldn't kibana 7 be compiled to be able to run under an updated centOS 6 anymore?
[root@kibana]# ldd /var/lib/kibana/headless_shell-linux/headless_shell
/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version 'GLIBC_2.14' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)
/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version 'GLIBC_2.15' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)
/var/lib/kibana/headless_shell-linux/headless_shell: /lib64/libc.so.6: version 'GLIBC_2.16' not found (required by /var/lib/kibana/headless_shell-linux/headless_shell)
...
libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007fb3d232a000)
libc.so.6 => /lib64/libc.so.6 (0x00007fb3d1f96000)[root@kibana]# nm /lib64/libc.so.6 | awk '$2=="A"{print}'
0000000000000000 A GLIBC_2.10
0000000000000000 A GLIBC_2.11
0000000000000000 A GLIBC_2.12
0000000000000000 A GLIBC_2.2.5
0000000000000000 A GLIBC_2.2.6
0000000000000000 A GLIBC_2.3
0000000000000000 A GLIBC_2.3.2
0000000000000000 A GLIBC_2.3.3
0000000000000000 A GLIBC_2.3.4
0000000000000000 A GLIBC_2.4
0000000000000000 A GLIBC_2.5
0000000000000000 A GLIBC_2.6
0000000000000000 A GLIBC_2.7
0000000000000000 A GLIBC_2.8
0000000000000000 A GLIBC_2.9
0000000000000000 A GLIBC_PRIVATE
[root@kibana]# cat /etc/centos-release
CentOS release 6.10 (Final)
TIA