NETBEARS - Blog | ElasticSearch cluster on Ubuntu

ElasticSearch cluster on Ubuntu

This is a tutorial on how to deploy an autoscaling ElasticSearch cluster on Ubuntu in AWS using CloudFormation.

The CloudFormation template is posted on GitHub and contains all you need to have the stack up and running.

Run the CloudFormation template with AWS CLI

``` git clone https://github.com/NETBEARS/elasticsearch-cluster-ubuntu.git aws cloudformation create-stack \ --stack-name elasticsearch-cluster-ubuntu \ --template-body file://cloudformation-template.yaml \ --parameters \ ParameterKey=Ami,ParameterValue=ami-6e1a0117 \ ParameterKey=AsgMaxSize,ParameterValue=8 \ ParameterKey=AsgMinSize,ParameterValue=2 \ ParameterKey=EmailAlerts,ParameterValue=email_for_alerts@domain.com \ ParameterKey=InstanceType,ParameterValue=m4.large \ ParameterKey=KeyName,ParameterValue=YOUR_INSTANCE_KEY \ ParameterKey=VpcId,ParameterValue=VPC_ID \ ParameterKey=SubnetID1,ParameterValue=SUBNET_IN_VPC_ID_1 \ ParameterKey=SubnetID2,ParameterValue=SUBNET_IN_VPC_ID_2 \ --capabilities CAPABILITY_IAM ```

Run the CloudFormation template in the AWS Console

Login to the AWS console and browse to the CloudFormation section
Select the cloudformation-template.yaml file
Before clicking "Create", make sure that you scroll down and tick the “I acknowledge that AWS CloudFormation might create IAM resources” checkbox
...drink coffee...
Go to the URL in the output section for the environment that you want to access

Resources created

1 AutoScaling Group
1 Elastic Load Balancer
1 S3 bucket (for data backup)
1 SNS topic (send monitoring alerts)

Autoscaling

The autoscaling groups uses the CpuUtilization alarm to autoscale automatically.

Because of this, you wouldn't have to bother making sure that your hosts can sustain the load.

Alarms

In order to be sure that you have set up the proper limits for your containers, the following alerts have been but into place:

NetworkInAlarm
RAMAlarmHigh
NetworkOutAlarm
IOWaitAlarmHigh
StatusAlarm

These CloudWatch alarms will send an email each time the limits are hit so that you will always be in control of what happens with your stack.

Monitoring

The stack launches NodeExporter (Prometheus exporter for hardware and OS metrics exposed by *NIX kernels, written in Go with pluggable metric collectors) on each host inside the cluster.

To view the monitoring data, all you need to setup is a Prometheus host and a Grafana dashboard and you're all set.

Data persistency

Due to the mechanics behind ElasticSearch, you don't need to set up any sort of data persistency, as the application itself ensures that all data is being replicated continuously throughout all existing and later-on created hosts.

Backup

Although the data persistency is covered, we should still have a backup for the data, just to be sure.

Because of this, a cronjob has been set up to run every 3 days on the ASG hosts that dump the data in an S3 bucket that is created inside the template.