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Last pushed: 2 years ago
Short Description
Elasticsearch (1.7.0) cluster on top of Kubernetes made easy.
Full Description

kubernetes-elasticsearch-cluster

Elasticsearch (1.7.1) cluster on top of Kubernetes made easy.

Elasticsearch best-practices recommend to separate nodes in three roles:

  • Master nodes - intended for clustering management only, no data, no HTTP API
  • Load-balancer nodes - intended for client usage, no data, with HTTP API
  • Data nodes - intended for storing and indexing your data, no HTTP API

Given this, I'm hereby making possible for you to scale as needed. For instance, a good strong scenario could be 3 Masters, 3 Load-balancers, 5 data-nodes.

Attention: As of the moment, Kubernetes pod descriptors use an emptyDir for storing data in each data node container. This is meant to be for the sake of simplicity and should be adapted according to your storage needs.

Pre-requisites

  • Docker 1.5+
  • Kubernetes cluster (tested with v1.0.1 on top of Vagrant + CoreOS)
  • kubectl configured to access your cluster master API Server

Build images (optional)

Providing your own version of the images automatically built from this repository will not be supported. This is an optional step. You have been warned.

Test

Deploy

kubectl create -f service-account.yaml
kubectl create -f elasticsearch-discovery-service.yaml
kubectl create -f elasticsearch-service.yaml
kubectl create -f elasticsearch-master-controller.yaml

Wait until elasticsearch-master-controller is provisioned, and

kubectl create -f elasticsearch-lb-controller.yaml

Wait until elasticsearch-data-controller is provisioned, and

kubectl create -f elasticsearch-data-controller.yaml

Validate

I leave to you the steps to validate the provisioned pods, but first step is to wait for containers to be in RUNNING state and check the logs of the master (as in Elasticsearch):

kubectl get pods

You should see something like this:

$ kubectl get pods
NAME                         READY     STATUS    RESTARTS   AGE
elasticsearch-data-881wf     1/1       Running   0          47s
elasticsearch-lb-tujlb       1/1       Running   0          1m
elasticsearch-master-hh4gw   1/1       Running   0          2m

Copy master pod identifier and check the logs:

kubectl logs elasticsearch-master-hh4gw
log4j:WARN No such property [maxBackupIndex] in org.apache.log4j.DailyRollingFileAppender.
log4j:WARN No such property [maxBackupIndex] in org.apache.log4j.DailyRollingFileAppender.
log4j:WARN No such property [maxBackupIndex] in org.apache.log4j.DailyRollingFileAppender.
[2015-07-22 13:53:12,234][WARN ][bootstrap                ] Unable to lock JVM memory (ENOMEM). This can result in part of the JVM being swapped out. Increase RLIMIT_MEMLOCK (ulimit).
[2015-07-22 13:53:12,375][INFO ][node                     ] [American Samurai] version[1.7.0], pid[1], build[929b973/2015-07-16T14:31:07Z]
[2015-07-22 13:53:12,377][INFO ][node                     ] [American Samurai] initializing ...
[2015-07-22 13:53:12,513][INFO ][plugins                  ] [American Samurai] loaded [cloud-kubernetes], sites []
[2015-07-22 13:53:12,551][INFO ][env                      ] [American Samurai] using [1] data paths, mounts [[/data (/dev/sda9)]], net usable_space [14.4gb], net total_space [15.5gb], types [ext4]
[2015-07-22 13:53:16,445][INFO ][node                     ] [American Samurai] initialized
[2015-07-22 13:53:16,446][INFO ][node                     ] [American Samurai] starting ...
[2015-07-22 13:53:16,676][INFO ][transport                ] [American Samurai] bound_address {inet[/0:0:0:0:0:0:0:0:9300]}, publish_address {inet[/10.244.78.4:9300]}
[2015-07-22 13:53:16,709][INFO ][discovery                ] [American Samurai] elasticsearch-k8s/dlkCkOJaQ4SkfUPfAPNubQ
[2015-07-22 13:53:22,631][INFO ][cluster.service          ] [American Samurai] new_master [American Samurai][dlkCkOJaQ4SkfUPfAPNubQ][elasticsearch-master-hh4gw][inet[/10.244.78.4:9300]]{data=false, master=true}, reason: zen-disco-join (elected_as_master)
[2015-07-22 13:53:22,666][INFO ][node                     ] [American Samurai] started
[2015-07-22 13:53:22,704][INFO ][gateway                  ] [American Samurai] recovered [0] indices into cluster_state
[2015-07-22 13:54:24,682][INFO ][cluster.service          ] [American Samurai] added {[Warlock][zvGs3UQ8QE-uxBaqXF5Prw][elasticsearch-lb-tujlb][inet[/10.244.78.5:9300]]{data=false, master=false},}, reason: zen-disco-receive(join from node[[Warlock][zvGs3UQ8QE-uxBaqXF5Prw][elasticsearch-lb-tujlb][inet[/10.244.78.5:9300]]{data=false, master=false}])
[2015-07-22 13:54:54,744][INFO ][cluster.service          ] [American Samurai] added {[Mastermind of the UK][fpkffLbzTTy0P4ox10xJxg][elasticsearch-data-881wf][inet[/10.244.78.6:9300]]{master=false},}, reason: zen-disco-receive(join from node[[Mastermind of the UK][fpkffLbzTTy0P4ox10xJxg][elasticsearch-data-881wf][inet[/10.244.78.6:9300]]{master=false}])

As you can assert, the cluster is up and running. Easy, wasn't it?

Scale

Scaling each type of node to handle your cluster is as easy as:

kubectl scale --replicas=3 rc elasticsearch-master
kubectl scale --replicas=2 rc elasticsearch-lb
kubectl scale --replicas=5 rc elasticsearch-data

Access the service

Don't forget that services in Kubernetes are only acessible from containers in the cluster. For different behavior you should configure the creation of an external-loadbalancer, in your service. That's out of scope of this document, for now.

kubectl get service elasticsearch

You should see something like this:

$ kubectl get service elasticsearch
NAME            LABELS                                       SELECTOR                                     IP(S)           PORT(S)
elasticsearch   component=elasticsearch,role=load-balancer   component=elasticsearch,role=load-balancer   10.100.251.16   9200/TCP

From any host on your cluster (that's running kube-proxy):

curl http://10.100.251.16:9200

This should be what you see:

{
  "status" : 200,
  "name" : "Warlock",
  "cluster_name" : "elasticsearch-k8s",
  "version" : {
    "number" : "1.7.0",
    "build_hash" : "929b9739cae115e73c346cb5f9a6f24ba735a743",
    "build_timestamp" : "2015-07-16T14:31:07Z",
    "build_snapshot" : false,
    "lucene_version" : "4.10.4"
  },
  "tagline" : "You Know, for Search"
}

Or if you want to see cluster information:

curl http://10.100.251.16:9200/_cluster/health?pretty

This should be what you see:

{
  "cluster_name" : "elasticsearch-k8s",
  "status" : "green",
  "timed_out" : false,
  "number_of_nodes" : 3,
  "number_of_data_nodes" : 1,
  "active_primary_shards" : 0,
  "active_shards" : 0,
  "relocating_shards" : 0,
  "initializing_shards" : 0,
  "unassigned_shards" : 0,
  "delayed_unassigned_shards" : 0,
  "number_of_pending_tasks" : 0,
  "number_of_in_flight_fetch" : 0
}
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Comments (1)
cmoulliard
3 years ago

Hi,

Can you provide more info how to setup kubernetes (link, doc, ...) ?

Regards,

Charles