Production Ready Clickhouse Cluster

A Clickhouse-cluster implementation for production use

Components Used

Name:Version	Documentation	Purpose	Alternatives	Advantages
Terraform 1.5.4	Docs	Hardware Provisioner Initial Setup	Salt Ansible	1. Easy syntax 2. Sufficient community and documentation 3. Much better suited for hardware provisioning
Hetzner Provider 1.42.1	Docs	Deploying servers	Vultr DigitalOcean	1. Cheaper :) 2. Good community overlooking provider
Ansible 2.15.2	Docs	Automating Tasks	Salt	1. No footprint on target hosts
Ubuntu 22.04	Docs	Operating system	Debian Centos	1. Bigger community 2. Faster releases than debian 3. Bigger community than any other OS 4. Not cash grapping like centos (Yet :))
Victoriametrics latest	Docs	Time-series Database	InfluxDB Prometheus	1. High performance 2. Cost-effective 3. Scalable 4. Handles massive volumes of data 5. Good community and documentation
vmalert latest	Docs	Evaluating Alerting Rules	Prometheus Alertmanager	1. Works well with VictoriaMetrics 2. Supports different datasource types
vmagent latest	Docs	Collecting Time-series Data	Prometheus	1. Works well with VictoriaMetrics 2. Supports different data source types
Alertmanager latest	Docs	Handling Alerts	ElastAlert Grafana Alerts	1. Handles alerts from multiple client applications 2. Deduplicates, groups, and routes alerts 3. Can be plugged to multiple endpoints (Slack, Email, Telegram, Squadcast, ...)
Grafana latest	Docs	Monitoring and Observability	Prometheus Datadog New Relic	1. Create, explore, and share dashboards with ease 2.Huge community and documentation 3. Easy to setup and manage 4. Many out of the box solutions for visualization
Clickhouse latest	Docs	Super fast colomn based database	Casandra Postgresql sql	1. Supremely fast for OLAP 2. Good set of replication engines for every need 3. Able to handle two data sets with the same primary key (mergetree)
Nodeexporter latest	Docs	Hardware and OS Metrics	cAdvisor Collectd	1. Measure various machine resources 2. Pluggable metric collectors 3. Basic standard for node monitoing
Clickhouse Keeper latest	Docs	System cordinator, DDL handling, Metadata keeper	Zookeper	1. Perfect integration with clickhouse 2. Uses up much less ram 3. Configuration is compatible with zookeper which makes the migration a lot easier
Docker latest	Docs	Application Deployment and Management	containerd podman	1. Much more bells and wistels are included out of the box comparing to alternatives 2. Awsome community and documentation 3. Easy to work with

Before you begin

Note Each ansible role has a general and a specific Readme file. It is encouraged to read them before firing off

p.s: Start with the readme file of main setup playbook

• Create an Api on hetzner
• Create a server as terraform and ansible provisioner (Needless to say that ansible and terraform must be installed)
• Clone the project
• In modular_terraform folder create a terraform.tfvars
  • The file must contain the following variables
    • hcloud_token "APIKEY"
    • image_name = "ubuntu-22.04"
    • server_type = "cpx31"
    • location = "hel1"
• Run terraform init to create the required lock file
• Before firing off, run terraform plan to see if everything is alright
• Run terraform apply
• Go Drink a cup of coffe and come back in 10 minutes or so (Hopefully everything must be up and running by then (: )

Known issues

• No automation for scaling or maintenance (after the initial set up)
• Terraform is limited to Hetzner
• Grafana datasource must be set manually http://IP_ADDRESS_:8428

Work flow

• Run the following command for terraform to install dependencies and create the lock file

terraform init

• Run the following command and check if there are any problems with terraform

terraform plan

• Apply terraform modules and get started

terraform apply

• Check the replication schema on clickhouse cluster

clickhouse-client 
select * from system.clusters

• Check the replication schema on clickhouse cluster

clickhouse-client 
select * from kang.industry_data_distributed

Note Keep in mind that because of the replication engine which is being used in the demo db, each node only returns the chunk of data which it has and not the whole thing

• Checking the monitoring stack

Note All dashboard are provisioned To add custom dashbaord on load, add it to /Ansible/roles/Victoria_Metrics/files/Grafana/provisioning/dashboards as a .json file. It would automatically be loaded to Grafana Just keep in mind that you have to also copy the dashbaord using ansible to the remote destination

• To Clean up everything (including the nodes themselvs)

terraform destroy