Resolving the "Not Found mysqlclient Library" Error in Zabbix: A Comprehensive Guide

As an experienced DevOps engineer and long-time Zabbix user, I have faced my share of cryptic dependency errors while getting the monitoring tool up and running. And few are as notorious as the "configure: error: Not found mysqlclient library" message.

This MySQL connectivity issue has stumped me for hours in the past. And search forums are full of questions from admins struggling with an abrupt Zabbix installation failure due to missing underlying libraries.

So in this post, let me provide a foolproof and extensively commented guide to detect, troubleshoot and fix this roadblock. I will share tips accrued from documenting hundreds of Zabbix deployments and even include references to specific error messages.

The MySQL Dependency Bedeviling Zabbix

Before diving into the nitty-gritty, let‘s take a closer look at why Zabbix needs these MySQL client libraries in the first place.

As you may know, Zabbix employs a database repository to organize and retrieve all the infrastructure metrics it collects. This includes historical time-series performance data along with configuration metadata of hosts, alerts and monitoring items.

MySQL is a popular open source database used as the persistence layer for Zabbix. It provides a scalable, cost-efficient and self-hosted storage backend able to handle the volume of monitoring data generated.

But there is no direct linkage between the Zabbix server process and MySQL database. The mysqlclient library acts as the intermediary connector facilitating communication between the two. It enables converting requests/queries between Zabbix and MySQL formats in both directions.

Zabbix components requiring the mysqlclient library

This is why the mysqlclient library is an essential dependency for Zabbix during both compilation and runtime.

Now let‘s see how its absence manifests in concrete installation errors and steps to resolve them.

Troubleshooting the "MySQL Library Not Found" Error

The exact error message may vary slightly, but generally looks like:

checking for mysql_config... no 
configure: error: MySQL library not found

This is triggered when the Zabbix configure script fails to find the mysql_config binary that comes with the mysqlclient library. Other common variants are –

Could not find platform independent libraries <prefix>
Could not find the mysqlclient library

In all cases, the root cause is – the MySQL development libraries are missing on the system. Let‘s see how to fix this:

Step 1: Install the MySQL Development Package

First, we need to install the package that contains the mysqlclient library and other header files for building MySQL-based applications:

On RHEL/CentOS using yum package manager:

$ sudo yum install mysql-devel

On modern RHEL/CentOS 8 and variants like Rocky Linux, use dnf instead of yum:

$ sudo dnf install mysql-devel

This will pull the latest mysql-devel package from your enabled repositories and install it.

Step 2: Download MySQL Packages Manually

If your Zabbix server does not have internet access, you will need to manually download the required RPM packages:

MySQL devel package for RHEL/CentOS 7:
https://rpmfind.net/linux/rpm2html/search.php?query=mysql-devel

Shared libraries package:
http://rpm.pbone.net/index.php3/stat/3/srodzaj/1/search/mysql-shared

Make sure to choose the relevant distro and architecture like x86_64 while downloading the RPM file.

Also have all the dependent packages handy before installing.

Step 3: Re-run Zabbix Configure

Once mysql-devel and other MySQL libraries are installed, we are finally ready to attempt re-configuring Zabbix:

$ ../configure --with-mysql --enable-server --enable-agent --enable-ipv6 --with-net-snmp --with-libcurl

You should see it succeed this time and generate the Makefile.

Understanding MySQL‘s Role as Zabbix Backend

Now that you have fixed the immediate roadblock, it helps to better understand the critical role of MySQL and what makes it suitable to power a monitoring tool like Zabbix:

Storage of time-series data: Zabbix metrics like CPU utilization etc are timestamped values that vary over time. MySQL‘s flexible schema allows modelling time-series data efficiently via the history & trends tables.

Handling data at scale: A typical Zabbix instance may track hundreds of thousands of metrics across server infrastructure. MySQL provides horizontal scalability using sharding to handle such volumes with acceptable performance.

Query capabilities: Rich support for joins, indexing and cached queries allow fast data access even for adhoc reporting queries across years of archived monitoring data.

Durability and backups: Being an ACID-compliant durable database, MySQL guarantees safe storage of business critical monitoring data and simplifies backup pipelines via binary logging.

Let‘s now look at some best practices to secure and scale the MySQL deployment backing Zabbix.

Securing and Optimizing the Zabbix MySQL Instance

Here are 5 key measures to ensure optimal performance and safety of the integrated Zabbix-MySQL platform:

1. Restrict database access – Limit MySQL permission to accept TCP connections only from the Zabbix server itself using the GRANT command. Disable remote root access.

2. Time-series optimization – Tune MySQL buffer sizes for handling time-series workloads per Zabbix best practices, like increasing InnoDB log files.

3. Storage provisioning – Align storage IOPS to expected data ingestion rates so that write latency remains low even during peaks. Partitioning also helps.

4. Replication – Set up an asynchronous MySQL slave to offload backups and analytics queries without affecting the primary instance running the Zabbix workload.

5. Monitoring 😉 – Lastly, use Zabbix itself or external tools to track MySQL disk space, memory utilization, replication lag and other critical metrics.

Conclusion

I hope this guide served as a one-stop resource to troubleshoot and fix the infamous "MySQL library not found error" in Zabbix – while also explaining the underlying moving pieces. Though it caused me grief for hours in the past, the steps are actually straightforward once you know.

Setting up and operating Zabbix does require some deeper understanding of its database dependencies and how to optimize them. So do spend the time to follow database best practices around security, backups, replication and sharding to ensure a smooth monitoring experience.

Let me know in the comments if any part of this article can be further improved! I have helped debug hundreds of Zabbix instances and love sharing that experience.