How to install CockroachDB on Linux 8

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CockroachDB is a highly scalable and indestructible, distributed database management system. Here, you will learn how to install CockroachDB on Linux servers. #centlinux #linux #cockroachdb

What is CockroachDB? :

CockroachDB is an elastic, indestructible SQL database for modern applications. It is developed by Cockroach Labs as an alternative to Google Spanner and available in CockroachCloud, CockroachDB Enterprise and Core editions.

Core edition is free and open source. Whereas, Enterprise edition requires a license. You may find the CockroachDB Enterprise Pricing on their official website.

This Database Management System is designed to store copies of data in multiple stores in order to deliver speedy access. Replication is automated and node addition and removal is very easy.

You can easily scale a CockroachDB cluster from a single node on your laptop to thousands of server nodes.

CockroachDB is designed to run in the cloud and be resilient to failures. The result is a database that is described as “almost impossible” to take down. Even if multiple servers or an entire datacenter were to go offline, CockroachDB would keep services online.

Environment Specification:

We are using two minimal CentOS 8 virtual machines with following specifications.

Node 1

  • CPU – 3.4 Ghz (2 cores)
  • Memory – 2 GB
  • Storage – 20 GB
  • Operating System – CentOS 8.2
  • Hostname –
  • IP Address – /24

Node 2

  • CPU – 3.4 Ghz (2 cores)
  • Memory – 2 GB
  • Storage – 20 GB
  • Operating System – CentOS 8.2
  • Hostname –
  • IP Address – /24

Update Linux Server Packages:

Use a SSH client to connect with as root user.

It is a best practice to update your Linux server packages frequently, especially before installation or configuration of a new software.

With the help of dnf command, update installed packages in your Linux operating system.

# dnf update -y

Check the Linux distro and kernel version of your servers, that are being used in this installation guide.

# uname -r

# cat /etc/redhat-release
CentOS Linux release 8.2.2004 (Core)

Configure Name Resolution of Cluster Nodes:

Name resolution is very critical while setting up a Linux cluster. Because, if a node is unable to resolve the hostname of the other nodes, then the cluster setup will raise different type of errors.

For this purpose, you can either configure an Authoritative DNS server or simply use the local DNS resolver.

Here, we are configuring the local DNS resolver for hostname resolution of the cluster nodes.

Edit /etc/hosts file by using vim editor.

# vi /etc/hosts

Add following entries in this file. crdb-node-01 crdb-node-02

These entries are quiet enough to configure name resolution of your cluster nodes.

Setup Time Synchronization on Linux Server:

Just like any other clustering setup, CockroachDB cluster also requires time synchronization across all the nodes.

If it unable to synchronize time on any of the cluster node and cause a time drift of more than 500ms, then that node won’t be started until its time is synchronized with the other CockroachDB nodes.

In Red Hat based Linux distros, Chrony is the preferred NTP client/server since RHEL 7.

Therefore, you can install Chrony by using dnf command.

# dnf install -y chrony

Enable and start Chrony service by using following Linux command.

# systemctl enable --now chronyd.service

Execute the following command to check the NTP sources and time synchronization status.

# chronyc sources -v
210 Number of sources = 4

  .-- Source mode  '^' = server, '=' = peer, '#' = local clock.
 / .- Source state '*' = current synced, '+' = combined , '-' = not combined,
| /   '?' = unreachable, 'x' = time may be in error, '~' = time too variable.
||                                                 .- xxxx [ yyyy ] +/- zzzz
||      Reachability register (octal) -.           |  xxxx = adjusted offset,
||      Log2(Polling interval) --.      |          |  yyyy = measured offset,
||                                     |          |  zzzz = estimated error.
||                                 |    |           
MS Name/IP address         Stratum Poll Reach LastRx Last sample
^+>     2   6    17     2  -3915us[-2554us] +/-   94ms
^+>     3   6    17     2    +25ms[  +27ms] +/-   83ms
^+>     2   6    17     2    -40ms[  -39ms] +/-  134ms
^*               2   6    17     2  +3885us[+5131us] +/-   88ms

Install CockroachDB Prerequisites:

CockroachDB requires some software packages, that are usually preinstalled on a minimal installed CentOS 8 operating system.

However, you can also execute the dnf command to install these packages, if they are not already installed.

# dnf install -y glibc ncurses-libs tzdata

Install CockroachDB on Linux:

You can download CockroachDB Core edition, free of cost, from GitHub or Cockroach Labs website.

Download CockroachDB by using wget command.

# cd /tmp
# wget
--2020-10-30 22:52:11--
Resolving (,,, ...
Connecting to (||:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 73681901 (70M) [binary/octet-stream]
Saving to: âcockroach-v20.1.8.linux-amd64.tgzâ

cockroach-v20.1.8.l 100%[===================>]  70.27M   253KB/s    in 5m 50s

2020-10-30 22:58:04 (206 KB/s) - âcockroach-v20.1.8.linux-amd64.tgzâ saved [73681901/73681901]

Extract downloaded tarball by using tar command.

# tar xf cockroach-v20.1.8.linux-amd64.tgz

Create directories for CockroachDB software and related files.

# mkdir -p /opt/cockroachdb/{bin,certs,private}

Copy extracted files in /opt/cockroachdb/bin directory.

# cp -i cockroach-v20.1.8.linux-amd64/cockroach /opt/cockroachdb/bin/

Check the file permissions of the cockroach file.

# ls -al /opt/cockroachdb/bin/
total 163100
drwxr-xr-x. 2 root root        23 Oct 31 11:12 .
drwxr-xr-x. 5 root root        45 Oct 31 11:11 ..
-rwxr-xr-x. 1 root root 167014096 Oct 31 11:12 cockroach

Create a Linux user to own CockroachDB software and processes. Also grant the ownership of files to that user.

# useradd -r cockroach
# chown -R cockroach.cockroach /opt/cockroachdb/

Create a soft link for cockroach file in /usr/local/bin/ directory, to make it executable from anywhere.

# ln -s /opt/cockroachdb/bin/cockroach /usr/local/bin/cockroach

Verify the CockroachDB version by executing following command.

# cockroach version
Build Tag:    v20.1.8
Build Time:   2020/10/21 15:46:38
Distribution: CCL
Platform:     linux amd64 (x86_64-unknown-linux-gnu)
Go Version:   go1.13.9
C Compiler:   gcc 6.3.0
Build SHA-1:  ffd029f51aa134f2bce4a39ef1f3ad095c3856ad
Build Type:   release

Above steps (from start of this article) must be executed on each node to effectively install CockroachDB on Linux cluster. Whereas, the steps onwards are specific to nodes and must be executed on the mentioned nodes only.

Setup CockroachDB Secure Cluster on Linux:

You have install CockroachDB on Linux successfully. Now you need to configure Database Secure Cluster.

CockroachDB cluster can be configured in secure and insecure modes.

Configuration of CockroachDB cluster in Insecure mode is pretty simple but do not enforce encryption of inter-cluster communication.

Whereas, Secure mode uses SSL/TLS certificates to enforce encryption of inter-cluster communication and authorization.

First of all, you need to create a Certificate Authority (CA), that will be used to digitally sign any certificate that you will generate for your CockroachDB secure cluster.

You can use following cockroach command to create a certificate authority, or you can also create a certificate authority with openssl command.

# cockroach cert create-ca 
> --certs-dir=/opt/cockroachdb/certs 
> --ca-key=/opt/cockroachdb/private/ca.key

Generate a SSL/TLS certificate for our first CockroachDB node (crdb-node-01) with the help of following command.

# cockroach cert create-node 
> crdb-node-01 
> localhost 
> --certs-dir=/opt/cockroachdb/certs 
> --ca-key=/opt/cockroachdb/private/ca.key

Generate a SSL/TLS certificate for CockroachDB client by executing following command.

# cockroach cert create-client 
> root 
> --certs-dir=/opt/cockroachdb/certs 
> --ca-key=/opt/cockroachdb/private/ca.key

Copy the SSL/TLS certificates on other nodes of database cluster.

# scp /opt/cockroachdb/certs/* 
> root@crdb-node-02:/opt/cockroachdb/certs/
root@crdb-node-02's password:
ca.crt                                        100% 1111    27.5KB/s   00:00
client.root.crt                               100% 1099   857.5KB/s   00:00
client.root.key                               100% 1675     1.5MB/s   00:00
node.crt                                      100% 1159     1.0MB/s   00:00
node.key                                      100% 1679   108.7KB/s   00:00

Copy the Certificate Authority key on other nodes, so we can create SSL/TLS on that nodes.

# scp /opt/cockroachdb/private/* root@crdb-node-02:/opt/cockroachdb/private/
root@crdb-node-02's password:
ca.key                                        100% 1679    81.3KB/s   00:00

Connect to as root user by using ssh command.

Remove the Node certificate/key that we have generated on the crdb-node-01 node.

# rm -f /opt/cockroachdb/certs/node.*

Generate a SSL/TLS certificate for crdb-node-02 node as follows.

# cockroach cert create-node 
> crdb-node-02 
> localhost 
> --certs-dir=/opt/cockroachdb/certs 
> --ca-key=/opt/cockroachdb/private/ca.key

Create Systemd Service Unit:

To enable auto-start of CockroachDB server during Linux startup, you are required to create a systemd service unit.

Connect with as root user by using ssh command.

Create a systemd service unit file by using vim editor.

# vi /etc/systemd/system/cockroachdb.service

Add following directives in this file.

Description=Cockroach Database cluster node

ExecStart=/usr/local/bin/cockroach start --certs-dir=/opt/cockroachdb/certs --advertise-addr=crdb-node-01 --join=crdb-node-01,crdb-node-02


You need to replace the –advertise-addr with the hostname of the CockroachDB node on which you are creating this systemd service.

Enable and start CockroachDB service.

# systemctl enable --now cockroachdb.service
Created symlink /etc/systemd/system/ â /etc/systemd/system/cockroachdb.service.

Check the CockroachDB service ports to verify that the CockroachDB service is started without any error.

# ss -tulpn | grep cockroach
tcp     LISTEN   0        128                    *:8080                 *:*      users:(("cockroach",pid=1692,fd=9))
tcp     LISTEN   0        128                    *:26257                *:*      users:(("cockroach",pid=1692,fd=15))

Configure Linux Firewall:

CockroachDB default service ports are 8080/tcp for Web Admin UI, 26257/tcp for SQL interface.

You are required to allow both of above service ports in your Linux firewall.

# firewall-cmd --permanent --add-port={8080,26257}/tcp
# firewall-cmd --reload

Initialize CockroachDB Secure Cluster:

CockroachDB configuration are completed, now you can execute the following command on any CockroachDB node to initialize the cluster.

# cockroach init --certs-dir=/opt/cockroachdb/certs --host=crdb-node-01:26257
Cluster successfully initialized

Accessing CockroachDB SQL Shell:

Connect to crdb-node-01 SQL shell by using following command.

# cockroach sql --certs-dir=/opt/cockroachdb/certs --host=crdb-node-01:26257
# Welcome to the CockroachDB SQL shell.
# All statements must be terminated by a semicolon.
# To exit, type: q.
# Server version: CockroachDB CCL v20.1.8 (x86_64-unknown-linux-gnu, built 2020/10/21 15:46:38, go1.13.9) (same version as client)
# Cluster ID: 50a8b514-7e6f-4a4a-936e-8a4d68aa1007
# Enter ? for a brief introduction.

List down available databases in CockroachDB server.

root@crdb-node-01:26257/defaultdb> SHOW DATABASES;
(3 rows)

Time: 1.742219ms

Create a new database by using CREATE statement.

root@crdb-node-01:26257/defaultdb> CREATE DATABASE contacts;

Time: 11.39776ms

Create a new table in contacts database.

root@crdb-node-01:26257/defaultdb> USE contacts;

Time: 661.825µs

root@crdb-node-01:26257/contacts> CREATE TABLE emails (id INT PRIMARY KEY, email varchar(40));

Time: 164.404539ms

Insert a few rows in emails table.

root@crdb-node-01:26257/contacts> INSERT INTO emails VALUES (1,'');

Time: 2.482089ms

root@crdb-node-01:26257/contacts> INSERT INTO emails VALUES (2,'');

Time: 2.278789ms

root@crdb-node-01:26257/defaultdb> q

Now connect with second CockroachDB node, and check has changes been replicated to that database.

# cockroach sql --certs-dir=/opt/cockroachdb/certs --host=crdb-node-02:26257
# Welcome to the CockroachDB SQL shell.
# All statements must be terminated by a semicolon.
# To exit, type: q.
# Server version: CockroachDB CCL v20.1.8 (x86_64-unknown-linux-gnu, built 2020/10/21 15:46:38, go1.13.9) (same version as client)
# Cluster ID: 50a8b514-7e6f-4a4a-936e-8a4d68aa1007
# Enter ? for a brief introduction.
root@crdb-node-02:26257/defaultdb> SHOW DATABASES;
(4 rows)

Time: 10.066515ms

root@crdb-node-02:26257/defaultdb> USE contacts;

Time: 2.853712ms

root@crdb-node-02:26257/contacts> SELECT * FROM emails;
  id |       email
   1 |
   2 |
(2 rows)

Time: 123.407227ms

root@crdb-node-02:26257/contacts> q

Data has been replicated to second node, it shows that our CockroachDB cluster has been configured successfully.

Access CockroachDB Web Admin UI:

To access CockroachDB Web Admin UI, we require a user account. This user must be created within CockroachDB database.

Therefore, connect to SQL shell of any CockroachDB node and create a database user.

root@crdb-node-01:26257/defaultdb> CREATE USER ahmer WITH PASSWORD 'cockroach';

Time: 363.507317ms

You are also required to grant the admin privilege to ahmer user.

root@crdb-node-01:26257/defaultdb> GRANT admin TO ahmer;

Time: 1.425956943s

Open URL https://crdb-node-01:8080 in a web browser.

CockroachDB Web Login

Login as ahmer user.

CockroachDB Dashboard 1
CockroachDB Dashboard 2

Configure Load Balancer for CockroachDB Cluster:

Each node in CockroachDB cluster has its own SQL and Web Admin UI services, that can be access independently by using Node hostname or IP address.

Therefore, it is necessary to configure a reverse proxy load balancer, so the users/applications can access our cluster by a common address/port instead of accessing individual nodes with separate hostname/IP addresses.

For this purpose, you can use HAProxy to configure a software load balancer. You can easily generate a HAProxy configuration file by using cockroach command.

# cockroach gen haproxy --certs-dir=/opt/cockroachdb/certs --host=crdb-node-01

Check the content of haproxy.cfg file.

# cat haproxy.cfg

  maxconn 4096

    mode                tcp
    # Timeout values should be configured for your specific use.
    # See:
    timeout connect     10s
    timeout client      1m
    timeout server      1m
    # TCP keep-alive on client side. Server already enables them.
    option              clitcpka

listen psql
    bind :26257
    mode tcp
    balance roundrobin
    option httpchk GET /health?ready=1
    server cockroach1 $(hostname):26257 check port 8080

This file requires minor adjustments and then it will perfectly work on a HAProxy load balancer.

You can refer to our previous post to configure HAProxy load balancer.

Conclusion – Install CockroachDB on Linux:

In this article, you have learned, how to install CockroachDB on Linux. If you having difficulty understanding the steps in this article, then you should buy and read RHCSA Red Hat Enterprise Linux 8: Training and Exam Preparation Guide (EX200), First Edition (PAID LINK) by Asghar Ghori.