[elasticsearch] How to stop/shut down an elasticsearch node?

I want to restart an elasticsearch node with a new configuration. What is the best way to gracefully shut down an node?

Is killing the process the best way of shutting the server down, or is there some magic URL I can use to shut the node down?

If you just want to apply new config you don't need to shut it down.

$ sudo service elasticsearch restart

But if you want to shut it down anyway:

$ sudo service elasticsearch stop

OR

$ sudo systemctl stop elasticsearch.service

$ sudo systemctl restart elasticsearch.service

Docker:

docker restart <elasticsearch-container-name or id>

The Head plugin for Elasticsearch provides a great web based front end for Elasticsearch administration, including shutting down nodes. It can run any Elasticsearch commands as well.

If you can't find what process is running elasticsearch on windows machine you can try running in console:

netstat -a -n -o

Look for port elasticsearch is running, default is 9200. Last column is PID for process that is using that port. You can shutdown it with simple command in console

taskkill /PID here_goes_PID /F

use the following command to know the pid of the node already running.

curl -XGET 'http://localhost:9200/_nodes/process'

It took me an hour to find out the way to kill the node and could finally do it after using this command in the terminal window.

If you're running a node on localhost, try to use brew service stop elasticsearch

I run elasticsearch on iOS localhost.

This works for me on OSX.

pkill -f elasticsearch

Answer for Elasticsearch inside Docker:

Just stop the docker container. It seems to stop gracefully because it logs:

[INFO ][o.e.n.Node               ] [elastic] stopping ...

Stopping the service and killing the daemon are indeed the correct ways to shutdown a node. However, it's not recommended to do so directly if you want to take down a node for maintenance. In fact, if you don't have replicas you will lose data.

When you directly shutdown a node, Elasticsearch will wait for 1m (default time) for it to come back online. If it doesn't, then it will start to allocate the shards from that node to other nodes wasting lots of IO.

A typical approach would be to disable shard allocation temporarily by issuing:

PUT _cluster/settings
{
  "persistent": {
    "cluster.routing.allocation.enable": "none"
  }
}

Now, when you take down a node, ES won't try to allocate shard from that node to other nodes and you can perform you maintenance activity and then once the node is up, you can enable shard allocation again:

PUT _cluster/settings
{
  "persistent": {
    "cluster.routing.allocation.enable": "all"
  }
}

Source: https://www.elastic.co/guide/en/elasticsearch/reference/5.5/restart-upgrade.html

If you don't have replicas for all your indexes, then performing this type of activity will have downtime on some of the indexes. A cleaner way in this case would be to migrate all the shards to other nodes before taking the node down:

PUT _cluster/settings
{
  "transient" : {
    "cluster.routing.allocation.exclude._ip" : "10.0.0.1"
  }
}

This will move all shards from 10.0.0.1 to other nodes (will take time depending on the data). Once everything is done, you can kill the node, perform maintenance and get it back online. This is a slower operation and is not required if you have replicas.

(Instead of _ip, _id, _name with wildcards will work just fine.)

More information: https://www.elastic.co/guide/en/elasticsearch/reference/5.5/allocation-filtering.html

Other answers have explained how to kill a process.

Just in case you want to find PID of the instance and kill the process, assuming that the node is listening to port 9300 (the default port) you can run the following command :

kill -9  $(netstat -nlpt | grep 9200 | cut -d ' ' -f 58 | cut -d '/' -f 1)

You may have to play with the numbers in the above-mentioned code such as 58 and 1

Considering you have 3 nodes.

Prepare your cluster

export ES_HOST=localhost:9200

# Disable shard allocation
curl -X PUT "$ES_HOST/_cluster/settings" -H 'Content-Type: application/json' -d'
{
  "persistent": {
    "cluster.routing.allocation.enable": "none"
  }
}
'

# Stop non-essential indexing and perform a synced flush
curl -X POST "$ES_HOST/_flush/synced"

Stop elasticsearch service in each node

# check nodes
export ES_HOST=localhost:9200
curl -X GET "$ES_HOST/_cat/nodes"

# node 1
systemctl stop elasticsearch.service

# node 2
systemctl stop elasticsearch.service

# node 3
systemctl stop elasticsearch.service

Restarting cluster again

# start
systemctl start elasticsearch.service

# Reenable shard allocation once the node has joined the cluster
curl -X PUT "$ES_HOST/_cluster/settings" -H 'Content-Type: application/json' -d'
{
  "persistent": {
    "cluster.routing.allocation.enable": null
  }
}
'

Tested on Elasticseach 6.5

Source:

1. https://www.elastic.co/guide/en/elasticsearch/reference/6.5/stopping-elasticsearch.html
2. https://www.elastic.co/guide/en/elasticsearch/reference/6.5/rolling-upgrades.html

For Mac users using Homebrew (Brew) to install and manage services:

List your Brew services:

brew services

Do something with a service:

brew services start elasticsearch-full
brew services restart elasticsearch-full
brew services stop elasticsearch-full