I have been trying to install Elasticsearch, which, for version 7.x seemed easy, whereas for version 5.x is a pain in the neck. The whole ordeal exists because there is a slew of compatibility requirements between the Elasticseach, Django Haystack, Django CMS and other things. If someone has a nice table or a way to wrap their head around that, I'd be happy to hear it.
As to the actual question, after installing ES 5.x, I cannot seem to get it working.
user@user-desktop:~/sites/project-web/project$ sudo systemctl restart elasticsearch
user@user-desktop:~/sites/project-web/project$ curl -X GET localhost:9200
curl: (7) Failed to connect to localhost port 9200: Connection refused
user@user-desktop:~/sites/project-web/project$
Entities that are uncommented in /etc/elasticsearch/elasticsearch.yml
# ======================== Elasticsearch Configuration =========================
#
# NOTE: Elasticsearch comes with reasonable defaults for most settings.
# Before you set out to tweak and tune the configuration, make sure you
# understand what are you trying to accomplish and the consequences.
#
# The primary way of configuring a node is via this file. This template lists
# the most important settings you may want to configure for a production cluster.
#
# Please consult the documentation for further information on configuration options:
# https://www.elastic.co/guide/en/elasticsearch/reference/index.html
#
# ---------------------------------- Cluster -----------------------------------
#
# Use a descriptive name for your cluster:
#
cluster.name: project-search
#
# ------------------------------------ Node ------------------------------------
#
# Use a descriptive name for the node:
#
node.name: node-1
#
# Add custom attributes to the node:
#
#node.attr.rack: r1
#
# ----------------------------------- Paths ------------------------------------
#
# Path to directory where to store the data (separate multiple locations by comma):
#
#path.data: /path/to/data
#
# Path to log files:
#
#path.logs: /path/to/logs
# ----------------------------------- Memory -----------------------------------
#
# Lock the memory on startup:
#
#bootstrap.memory_lock: true
#
# Make sure that the heap size is set to about half the memory available
# on the system and that the owner of the process is allowed to use this
# limit.
#
# Elasticsearch performs poorly when the system is swapping the memory.
#
# ---------------------------------- Network -----------------------------------
#
# Set the bind address to a specific IP (IPv4 or IPv6):
#
network.host: 0.0.0.0
#
# Set a custom port for HTTP:
#
http.port: 9200
transport.host: localhost
transport.tcp.port: 9300
#
# For more information, consult the network module documentation.
# --------------------------------- Discovery ----------------------------------
#
# Pass an initial list of hosts to perform discovery when new node is started:
# The default list of hosts is ["127.0.0.1", "[::1]"]
#
#discovery.zen.ping.unicast.hosts: ["host1", "host2"]
discovery.zen.ping.unicast.hosts: ["0.0.0.0"]
#discovery.seed_hosts:["0.0.0.0"]
#
# Prevent the "split brain" by configuring the majority of nodes (total number of master-eligible nodes / 2 + 1):
#
discovery.zen.minimum_master_nodes: 1
#
# For more information, consult the zen discovery module documentation.
#
# ---------------------------------- Gateway -----------------------------------
#
# Block initial recovery after a full cluster restart until N nodes are started:
#
#gateway.recover_after_nodes: 3
#
# For more information, consult the gateway module documentation.
#
# ---------------------------------- Various -----------------------------------
#
# Require explicit names when deleting indices:
#
#action.destructive_requires_name: true
This is the status with which it fails:
user@user-desktop:~/sites/project-web/project$ systemctl status elasticsearch.service
ā elasticsearch.service - Elasticsearch
Loaded: loaded (/usr/lib/systemd/system/elasticsearch.service; enabled; vendor preset: enabled)
Active: failed (Result: exit-code) since Sun 2019-11-24 15:39:25 CST; 3min 54s ago
Docs: http://www.elastic.co
Process: 19098 ExecStart=/usr/share/elasticsearch/bin/elasticsearch -p ${PID_DIR}/elasticsearch.pid --quiet -Edefault.path.logs=${LOG_DIR} -Edefault.path.data=${DATA_DIR} -Edefault.path.conf=${CONF_DI
Process: 19097 ExecStartPre=/usr/share/elasticsearch/bin/elasticsearch-systemd-pre-exec (code=exited, status=0/SUCCESS)
Main PID: 19098 (code=exited, status=1/FAILURE)
Nov 24 15:39:24 user-desktop systemd[1]: Starting Elasticsearch...
Nov 24 15:39:24 user-desktop systemd[1]: Started Elasticsearch.
Nov 24 15:39:24 user-desktop elasticsearch[19098]: OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
Nov 24 15:39:25 user-desktop systemd[1]: elasticsearch.service: Main process exited, code=exited, status=1/FAILURE
Nov 24 15:39:25 user-desktop systemd[1]: elasticsearch.service: Failed with result 'exit-code'.
In /var/log/elasticsearch/project-search.log I find the following error:
[2019-11-24T15:46:44,319][INFO ][o.e.n.Node ] [node-1] initializing ...
[2019-11-24T15:46:44,410][ERROR][o.e.b.Bootstrap ] Exception
org.elasticsearch.ElasticsearchException: java.io.IOException: failed to read [id:0, legacy:false, file:/var/lib/elasticsearch/nodes/0/_state/node-0.st]
at org.elasticsearch.ExceptionsHelper.maybeThrowRuntimeAndSuppress(ExceptionsHelper.java:196) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.gateway.MetaDataStateFormat.loadLatestState(MetaDataStateFormat.java:335) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.env.NodeEnvironment.loadOrCreateNodeMetaData(NodeEnvironment.java:418) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.env.NodeEnvironment.<init>(NodeEnvironment.java:267) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.node.Node.<init>(Node.java:265) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.node.Node.<init>(Node.java:245) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Bootstrap$5.<init>(Bootstrap.java:233) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Bootstrap.setup(Bootstrap.java:233) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Bootstrap.init(Bootstrap.java:342) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Elasticsearch.init(Elasticsearch.java:132) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Elasticsearch.execute(Elasticsearch.java:123) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.cli.EnvironmentAwareCommand.execute(EnvironmentAwareCommand.java:70) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.cli.Command.mainWithoutErrorHandling(Command.java:134) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.cli.Command.main(Command.java:90) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:91) [elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.bootstrap.Elasticsearch.main(Elasticsearch.java:84) [elasticsearch-5.6.16.jar:5.6.16]
Caused by: java.io.IOException: failed to read [id:0, legacy:false, file:/var/lib/elasticsearch/nodes/0/_state/node-0.st]
at org.elasticsearch.gateway.MetaDataStateFormat.loadLatestState(MetaDataStateFormat.java:328) ~[elasticsearch-5.6.16.jar:5.6.16]
... 14 more
Caused by: java.lang.IllegalArgumentException: [node_meta_data] unknown field [node_version], parser not found
at org.elasticsearch.common.xcontent.ObjectParser.getParser(ObjectParser.java:399) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.common.xcontent.ObjectParser.parse(ObjectParser.java:159) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.common.xcontent.ObjectParser.apply(ObjectParser.java:183) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.env.NodeMetaData$1.fromXContent(NodeMetaData.java:110) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.env.NodeMetaData$1.fromXContent(NodeMetaData.java:94) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.gateway.MetaDataStateFormat.read(MetaDataStateFormat.java:203) ~[elasticsearch-5.6.16.jar:5.6.16]
at org.elasticsearch.gateway.MetaDataStateFormat.loadLatestState(MetaDataStateFormat.java:323) ~[elasticsearch-5.6.16.jar:5.6.16]
... 14 more
Could someone tell me what it going on? Any help on resolving this and getting ES to work would be appreciated.
Looks like an inconsistency issue between elasticSearch versions. If you had data indexed previously with ES version 7.0, now that data in that instance in the disk is incompatible with ES version 5.0.