Containers and Clusters

Containers and problems they solve

We have already discussed the containers and their advantages over traditional software development methodologies. As we know, they are an ideal choice for implementing the microservices architecture and drastically simplify the application deployment process for us. For example, if we are building a web application that has front-end and back-end components. We can create separate containers for the frontend, backend, and databases. Each of these containers can be deployed and scaled independently of each other.

When it comes to running the containers, we have a few options that we can use. One of the most straightforward options would be to spin up a VM and run all of our containers in that VM. By now, we understand that running a single VM doesn't guarantee high availability and is not a good solution for scaling our application. We have a single point of failure. If a VM goes down, our application goes down. This is where clusters can help us.

Using clusters to run containers

A cluster provides all the benefits, as we have already discussed, to container-based applications. Rather than running containers in a single VM, we can use a cluster of VMs to run containers that form our application. We can improve the availability, scalability, and performance of our application by using a cluster.

Everything works fine until a point, but container management becomes difficult as we run more containers.

Container management

When dealing with a couple of containers, running them on their own is fine. However, as we keep adding more containers, we must think of better strategies to manage them effectively. Otherwise, we’ll be doing a lot of manual and tedious work to keep our containers running and to ensure their health and security. This is where we can use container orchestration..

Container orchestrators help us automate the operational effort required to run container-based workloads. They take care of things like managing the lifecycle of containers, provisioning, deployment, scaling, load balancing, etc.

Kubernetes

Kubernetes is an open-source platform for managing containerized workloads. It was created by Google to run their massive-scale applications and was later made open source. The Cloud Native Computing Foundation (CNCF) now manages it. Kubernetes provides a framework to run distributed systems resiliently. It handles the scale and failover of applications. It has become a de facto standard for running container-based applications.

Architecturally, Kubernetes is a cluster, as shown in the reference architecture below: