Service starts but connections refused on public IP and localhost

[Ant]

OK the story so far:

upgraded dev box from 5.6.6 to 6.2.4 for more info see

Upgrade from 5.6.6 to 6.2.4, elastic failed to start

Continuing the discussion from Elasticsearch Service won't start after full cluster upgrade from 5.4 to 6.0: I'm mid upgrade from 5.6.6. to 6.2.4 and haivng an issue getting elastic to start, if I look in /usr/lib/systemd/system/elasticsearch.service I also see the line with -Edefault.path.conf=${CONF_DIR} I have added path.config and path.log to the elasticsearch.yml file opened /etc/sysconfig/elasticsearch and added ES_PATH_CONF=/etc/elasticsearch but when I try to start it I'm getting ●…

FYI this is a 1 node cluster, prod is 3 nodes but I need to get dev done first.

I've now got the elastic service to start, if I use the elasticserach.yml.rpmnew as my elasticserach.yml which only contains path.data: /var/lib/elasticsearch, path.logs: /var/log/elasticsearch then I can fire curl -XGET -u user:password 'http://localhost:9200/_cat/indices?v' I get back a list of all the indexs that were there before the upgrade.

when I add network.host: 192.168.100.22 I get no responce on either localhost or the boxes IP.

if anyone has any suggestions then I'd be very greatful for them.

[Ant]

in the logs I've found

[2018-04-20T11:59:06,347][INFO ][o.e.t.TransportService   ] [HOC_bIV] publish_address { 192.168.100.22:9300}, bound_addresses { 192.168.100.22:9300}
[2018-04-20T11:59:06,414][INFO ][o.e.b.BootstrapChecks    ] [HOC_bIV] bound or publishing to a non-loopback address, enforcing bootstrap checks
[2018-04-20T11:59:06,447][ERROR][o.e.b.Bootstrap          ] [HOC_bIV] node validation exception
[1] bootstrap checks failed
[1]: max number of threads [2048] for user [elasticsearch] is too low, increase to at least [4096]
[2018-04-20T11:59:06,453][INFO ][o.e.n.Node               ] [HOC_bIV] stopping ...
[2018-04-20T11:59:06,541][INFO ][o.e.n.Node               ] [HOC_bIV] stopped
[2018-04-20T11:59:06,541][INFO ][o.e.n.Node               ] [HOC_bIV] closing ...
[2018-04-20T11:59:06,562][INFO ][o.e.n.Node               ] [HOC_bIV] closed

so looked up how to increase this and found https://www.elastic.co/guide/en/elasticsearch/reference/5.2/_maximum_number_of_threads_check.html

edited /etc/security/limits.conf to include

elasticsearch - nproc 4096
root - nproc 4096

but I still get the same error

[Ant]

resolved it

in /usr/lib/systemd/system/elasticsearch.service the NPROC limit was set to 2048 so regardless of what I did in limits.conf it wouldn't change, I had to edit it in that to get it to load.