Using Portworx to Deploy and Manage an HA MySQL Cluster on IBM Cloud Kubernetes Service
27 min read
IBM Cloud Kubernetes Service and Portworx
IBM Cloud Kubernetes Service is a managed Kubernetes offering running in IBM Cloud. It is designed to deliver powerful tools, intuitive user experience, and built-in security for rapid delivery of applications that can be bound to cloud services related to IBM Watson, IoT, DevOps, and data analytics. As a CNCF-certified Kubernetes provider, IBM Cloud Kubernetes Service provides intelligent scheduling, self-healing, horizontal scaling, service discovery and load balancing, automated rollouts and rollbacks, and secret and configuration management. The service also has advanced capabilities around simplified cluster management, container security, and isolation policies, the ability to design a cluster with a custom configuration and integrated operational tools for consistency in deployment.
Portworx is a Kubernetes storage and data management platform that enables enterprises to confidently run mission-critical data services on IBM Cloud Kubernetes Service (as well as IBM Cloud Private). The addition of primitives (such as stateful sets and persistent volumes) to Kubernetes has made it possible, in theory, to run stateful services like databases on Kubernetes. But, these primitives alone do not address the core business challenges associated with running data-rich applications on Kubernetes: high availability, backup and recovery, data security, SLA-management, and more. Portworx provides a single data-management layer for all stateful services that directly addresses these challenging topics.
I’m really excited to work with Portworx and Janakiram MSV (@janakiramm), architect and advisor with Portworx, on this tutorial. The rest of the blog was authored by Jani.
Tutorial
This tutorial is a walkthrough of the steps involved in deploying and managing a highly available MySQL cluster on IBM Cloud Kubernetes Service.
In summary, to run HA MySQL on IBM Cloud Kubernetes Service you need to do the following:
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Launch an IBM Cloud Kubernetes Service cluster running on bare metal servers with software-defined storage (SDS).
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Install a cloud-native storage solution like Portworx as a Daemonset on IBM Cloud Kubernetes Service.
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Create a storage class defining your storage requirements like replication factor, snapshot policy, and performance profile,
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Deploy MySQL using Kubernetes,
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Test failover by killing or cordoning node in your cluster.
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Expand the volume size dynamically.
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Perform backup and restore through snapshots.
Launching an IBM Cloud Kubernetes Service Cluster
For running stateful workloads in a production environment backed by Portworx, it is highly recommended to launch an IBM Cloud Kubernetes Service cluster based on bare metal servers and software-defined storage. The minimum requirements of a worker node to successfully run Portworx include:
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4 CPU cores
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4GB memory
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128GB of raw unformatted storage
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10Gbps network speed
For details on launching a Kubernetes cluster with bare metal worker nodes, please refer to the documentation of IBM Cloud Kubernetes Service.
We are using an IBM Cloud Kubernetes Service cluster with four nodes, out of which three nodes are running bare metal servers with SDS based on the instance type ms2c.4x32.1.9tb.ssd.encrypted
. Only these machines that meet the prerequisite would be used by Portworx.
When we filter the nodes based on the label, we see the below nodes:
To exclude nodes that don’t meet Portworx prerequisites, you can apply a label to skip the installation of Portworx. For example, the below command applies a label on the node with name 10.185.22.14
which doesn’t run on a bare metal server:
Installing Portworx on IBM Cloud Kubernetes Service
Installing Portworx on IBM Cloud Kubernetes Service is not very different from installing it on any other Kubernetes cluster. It is recommended that you create an etcd instance through Compose for etcd. You can use the Helm Chart to install a Portworx cluster in IBM Cloud Kubernetes Service. Portworx documentation for IBM Cloud Kubernetes Service has the prerequisites and instructions to install and configure Portworx, STORK, and other components.
At the end of the installation, we will have Portworx Daemonset running on the nodes, excluding those that are filtered out in the previous step:
Creating a Kubernetes storage class for MySQL
Once the IBM Cloud Kubernetes Service cluster is up and running and Portworx is installed and configured, we will deploy a highly available MySQL database.
Through Kubernetes storage class objects, an admin can define different classes of Portworx volumes that are offered in a cluster. These classes will be used during the dynamic provisioning of volumes. The Storage Class defines the replication factor, I/O profile (e.g., for a database or a CMS), and priority (e.g., SSD or HDD). These parameters impact the availability and throughput of workloads and can be specified for each volume. This is important because a production database will have different requirements than a development Jenkins cluster.
In this example, the storage class that we deploy has a replication factor of 3 with I/O profile set to “db,” and priority set to “high.” This means that the storage will be optimized for low latency database workloads like MySQL and automatically placed on the highest performance storage available in the cluster. Notice that we also mention the filesystem—xfs—in the storage class:
Creating a MySQL PVC on Kubernetes
We can now create a Persistent Volume Claim (PVC) based on the Storage Class. Thanks to dynamic provisioning, the claims will be created without explicitly provisioning Persistent Volume (PV):
Deploying MySQL on IBM Cloud Kubernetes Service
Finally, let’s create a MySQL instance as a Kubernetes deployment object. For simplicity’s sake, we will just be deploying a single MySQL pod. Because Portworx provides synchronous replication for High Availability, a single MySQL instance might be the best deployment option for your MySQL database. Portworx can also provide backing volumes for multi-node MySQL cluster. The choice is yours:
The MySQL deployment defined above is explicitly associated with the PVC, px-mysql-pvc
created in the previous step.
This deployment creates a single pod running MySQL backed by Portworx:
We can inspect the Portworx volume by accessing the pxctl tool running with the MySQL pod:
The output from the above command confirms the creation of volumes that are backing MySQL database instance.
Failing over MySQL pod on Kubernetes
Populating sample data
Let’s populate the database with some sample data.
We will first find the pod that’s running MySQL to access the shell:
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.6.40 MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>
Now that we are inside the shell, we can populate create a sample database and table:
Let’s run a few queries on the table.
mysql> select `officeCode`,`city`,`phone`,`addressLine1`,`city` from `offices`;
7 rows in set (0.01 sec)
Find all the offices in the USA:
mysql> select `officeCode`, `city`, `phone` from `offices` where `country` = "USA";
3 rows in set (0.00 sec)
Exit from the MySQL shell to return to the host:
Simulating node failure
Now, let’s simulate the node failure by cordoning off the node on which MySQL is running:
The above command disabled scheduling on one of the nodes:
Now, let’s go ahead and delete the MySQL pod:
As soon as the pod is deleted, it is relocated to the node with the replicated data. STorage ORchestrator for Kubernetes (STORK), Portworx’s custom storage scheduler, allows co-locating the pod on the exact node where the data is stored. It ensures that an appropriate node is selected for scheduling the pod.
Let’s verify this by running the below command. We will notice that a new pod has been created and scheduled in a different node:
Finally, let’s verify that the data is still available.
Verifying that the data is intact
Let’s find the pod name and run the ‘exec’ command and then access the MySQL shell:
Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 1 Server version: 5.6.40 MySQL Community Server (GPL) Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql>
We will query the database to verify that the data is intact:
3 rows in set (0.00 sec)
Observe that the database table is still there and all the content is intact. Exit from the client shell to return to the host.
Performing storage operations on MySQL
After testing end-to-end failover of the database, let’s perform StorageOps on our IBM Cloud Kubernetes Service cluster.
Expanding the Kubernetes Volume with no downtime
Currently, the Portworx volume that we created at the beginning is 1Gib in size. We will now expand it to double the storage capacity.
First, let’s get the volume name and inspect it through the pxctl
tool:
Notice the current Portworx volume. It is 1GiB. Let’s expand it to 2GiB:
Check the new volume size:
Taking Snapshots of a Kubernetes volume and restoring the database
Portworx supports creating snapshots for Kubernetes PVCs.
Let’s create a snapshot for the Kubernetes PVC we created for MySQL:
Since snapshots are just like volumes—we can use it to start a new instance of MySQL. Let’s create a new instance of MySQL by restoring the snapshot data:
From the new PVC, we will create a MySQL pod:
Verify that the new pod is in a Running state:
Finally, let’s access the sample data created earlier in the walk-through:
3 rows in set (0.00 sec)
Notice that the collection is still there with the data intact. We can also push the snapshot to an Amazon S3-compatible object storage service if we want to create a disaster recovery backup in another region or location. Since Portworx snapshots work with any S3 compatible object storage, the backup can go to a different cloud or even an on-premises data center.
Summary
Portworx can be easily deployed on IBM Cloud Kubernetes Service to run stateful workloads in production. Through the integration of STORK, DevOps and StorageOps teams can seamlessly run highly available database clusters in IBM Cloud Kubernetes Service. They can perform traditional operations such as volume expansion, backup, and recovery for the cloud-native applications in an automated and efficient manner.