rolling upgrade of elasticsearch (debian edition)

elastic-rolling-upgrade.sh

#!/bin/bash

# written according to
# https://www.elastic.co/guide/en/elasticsearch/reference/5.6/rolling-upgrades.html
# NO PLUGIN SUPPORT

# Dependencies
# - curl
# - jq

ELASTIC_HOST="${ELASTIC_HOST:-localhost}"
ELASTIC_PORT="${ELASTIC_PORT:-9200}"

echo "disabling shard allocation"
curl -s -X PUT "${ELASTIC_HOST}:${ELASTIC_PORT}/_cluster/settings" -H 'Content-Type: application/json' -d'
{
  "transient": {
    "cluster.routing.allocation.enable": "none"
  }
}
' | jq '.'

echo "stopping indexing and synced flush"
curl -s -X POST "${ELASTIC_HOST}:${ELASTIC_PORT}/_flush/synced" | jq '.'

# upgrade
systemctl stop elasticsearch
apt-get -y upgrade elasticsearch
systemctl daemon-reload
systemctl start elasticsearch

echo "waiting for node to come up"
until curl -s -X GET "${ELASTIC_HOST}:${ELASTIC_PORT}/_cat/nodes" | grep $(hostname); do
        echo -n "."
        sleep 1
done

echo "reenabling shard allocation"
curl -s -X PUT "${ELASTIC_HOST}:${ELASTIC_PORT}/_cluster/settings" -H 'Content-Type: application/json' -d'
{
  "transient": {
    "cluster.routing.allocation.enable": "all"
  }
}
' | jq '.'

echo "waiting for cluster status to become green again"
until curl -s -X GET "${ELASTIC_HOST}:${ELASTIC_PORT}/_cat/health" | grep green; do
        echo -n "."
        sleep 1
done