Unit files to deploy an ElasticSearch cluster on CoreOS via Fleet

README.md

What

Unit files to deploy an ElasticSearch cluster on CoreOS via Fleet.

Service discovery & registration is done via etcd.

elasticsearch-discovery@.service provides a dumb discovery service by registering an elasticsearch host if it should be up. elasticsearch-intelligent-discovery@.service registers the service only if it is running.

A service & timer unit for elasticsearch curator is provided which does some housekeeping.

Changes from digital-wonderland

Since CoreOS now uses etcd2 as fleet unit file, following changed: Discovery changed from requiring etcd to etcd2 Intelligent discovery is not needed (etcd2 is expected to run)

Usage

First load the necessary units:

$ fleetctl load elasticsearch-data@{1,2,3}.service elasticsearch-discovery@{1,2,3}.service elasticsearch@{1,2,3}.service

then start the first unit:

$ fleetctl start elasticsearch@1.service

after the unit is up and running start the others:

$ fleetctl start elasticsearch@{2,3}.service

elasticsearch-curator.service

[Unit]
Description=Elasticsearch Curator Service
Documentation=https://github.com/elasticsearch/curator
After=docker.service
Requires=docker.service

[Service]
TimeoutSec=0
EnvironmentFile=/etc/environment
ExecStartPre=/usr/bin/docker pull digitalwonderland/elasticsearch-curator
ExecStart=/bin/sh -c '\
  /usr/bin/docker run --rm digitalwonderland/elasticsearch-curator --host ${COREOS_PRIVATE_IPV4} optimize --prefix logstash- --older-than 1 --max_num_segments 1; \
  /usr/bin/docker run --rm digitalwonderland/elasticsearch-curator --host ${COREOS_PRIVATE_IPV4} delete --prefix logstash- --older-than 30; \
  /usr/bin/docker run --rm digitalwonderland/elasticsearch-curator --host ${COREOS_PRIVATE_IPV4} optimize --prefix .marvel- --older-than 1 --max_num_segments 1; \
  /usr/bin/docker run --rm digitalwonderland/elasticsearch-curator --host ${COREOS_PRIVATE_IPV4} delete --prefix .marvel- --older-than 30'

[X-Fleet]
# Wildcards are not supported: https://github.com/coreos/fleet/issues/494
#MachineOf=elasticsearch@*.service

elasticsearch-curator.timer

[Unit]
Description=Run Elasticsearch Curator Daily

[Timer]
OnBootSec=12h
OnUnitActiveSec=1d

[Install]
WantedBy=timers.target

[X-Fleet]
MachineOf=elasticsearch-curator.service

elasticsearch-data@.service

[Unit]
Description=Elasticsearch Data Volume
After=docker.service
Requires=docker.service
Before=elasticsearch@%i.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/bin/sh -c "docker inspect %p-%i >/dev/null 2>&1 || docker run --name %p-%i -v /var/lib/elasticsearch busybox chmod -R 0777 /var/lib/elasticsearch"

[X-Fleet]
Conflicts=%p@*.service
MachineOf=elasticsearch@%i.service

elasticsearch-discovery@.service

[Unit]
Description=Elasticsearch Discovery Service
After=etcd2.service
Requires=etcd2.service
Before=elasticsearch@%i.service
BindsTo=elasticsearch@%i.service

[Service]
EnvironmentFile=/etc/environment

ExecStart=/bin/bash -c '\
  while true; do \
    etcdctl set /services/elasticsearch/${COREOS_PRIVATE_IPV4} \'{"http_port": 9200, "transport_port": 9300}\' --ttl 60; \
    sleep 45; \
  done'

ExecStop=/usr/bin/etcdctl rm /services/elasticsearch/${COREOS_PRIVATE_IPV4}

[X-Fleet]
MachineOf=elasticsearch@%i.service

elasticsearch@.service

[Unit]
Description=Elasticsearch Service
Documentation=http://www.elasticsearch.org/guide/en/elasticsearch/reference/current/index.html
After=docker.service
Requires=docker.service
Requires=elasticsearch-data@%i.service
Requires=elasticsearch-discovery@%i.service

[Service]
TimeoutSec=0
Restart=always
RestartSec=1m
EnvironmentFile=/etc/environment
SuccessExitStatus=255

ExecStartPre=-/usr/bin/docker kill %p-%i
ExecStartPre=-/usr/bin/docker rm %p-%i
ExecStartPre=/usr/bin/docker pull digitalwonderland/elasticsearch

ExecStart=/bin/bash -c '\
  curl -f ${COREOS_PRIVATE_IPV4}:4001/v2/keys/services/elasticsearch; \
  if [ "$?" = "0" ]; then \
      UNICAST_HOSTS=$(etcdctl ls --recursive /services/elasticsearch \
                      | sed "s/\/services\/elasticsearch\///g" \
                      | sed "s/$/:9300/" \
                      | paste -s -d","); \
  else \
      UNICAST_HOSTS=""; \
  fi; \
  /usr/bin/docker run \
    --rm \
    --name %p-%i \
    --publish 9200:9200 \
    --publish 9300:9300 \
    --volumes-from elasticsearch-data-%i \
    -e ELASTICSEARCH_CLUSTER_NAME=logstash \
    digitalwonderland/elasticsearch \
    -Des.node.name=%p-%i \
    -Des.network.publish_host=${COREOS_PRIVATE_IPV4} \
    -Des.discovery.zen.ping.multicast.enabled=false \
    -Des.discovery.zen.ping.unicast.hosts=$UNICAST_HOSTS'

ExecStop=/usr/bin/docker stop %p-%i
ExecStopPost=-/usr/bin/docker rm %p-%i

[X-Fleet]
Conflicts=%p@*.service