Introduction
As Kubernetes continues to grow and evolve, one question that has risen is - do we need multi-container pods?
In this blog post, we will explore the reasons behind using them and the advantages they provide over single-container pods.
What are Multi-Container Pods?
A multi-container pod is a pod that contains more than one container within the same pod specification. All containers within a multi-container pod share the same Kubernetes node, namespace, and network. They can also share volumes and have access to the container state and processes.
The containers within a multi-container pod can coordinate and share functionality to provide additional functionalities to the pod. For example, you can run an application server and a database server in the same pod, so they can communicate via localhost.
Why Use Multi-Container Pods?
There are several compelling reasons to use multi-container pods:
1. Complex Applications
Some applications consist of several components that need to work together as a single unit. Using multi-container pods, we can deploy and manage these complex applications as a single entity, with no need to worry about container interdependence or communication.
2. Sharing Resources
Containers in a multi-container pod can share resources, such as volumes and network interfaces, which simplifies administration while still providing the runtime isolation that containers are known for.
3. Operational Convenience
Multi-container pods use just one pod specification to create and deploy several containers in a single pod with just one kubectl apply command. Multiple containers in a single pod allow an operator to consolidate pod-related functionality and reduce the amount of coordination needed to manage several pods.
4. Security
Multi-container pods can be more secure than having multiple, single-container pods. Using a single pod to run multiple containers can sometimes simplify security and reduce the risk of exposure to the Kubernetes API server.
Advantages of Multi-Container Pods
Let's now dive into the advantages of using multi-container pods:
1. Simplifies Interdependent Components
When multiple components are necessary for an application to function correctly, each component can be containerized and deployed within the same multi-container pod. This simplifies deployment management since interdependent components may be deployed in a way to reduce the complexity of managing large, interdependent components.
2. Simplifies Management of Stateful Pods
Multi-container pods provide a way to manage stateful applications easier. For example, running with a database, Elasticsearch, and file storage containers in the same part allows these persistent data components to have simpler and more centralized management.
3. Reduces Overhead
Multi-container pods reduce overhead. If several pods need a service to run, like logging or monitoring, with a single pod running all the related services, it will be easier to manage since it will be in a more consolidated manner.
4. Resource Management
The capacity of the container can be shared to limit the resources of the pod, ensuring that an individual container doesn't claim all resources allocated to the pod.
Conclusion
Multi-container pods in Kubernetes are an excellent way to simplify the deployment and management of complex applications. They also provide a way to centralize the management of persistent data that is related to the application. They offer a convenient way of managing intra-pod communication, as well as sharing resources, reducing overhead and managing resources more efficiently.
When it comes to container modularity, multi-container pods are a significant step forward, and as Kubernetes continues to grow and evolve, the use cases and possibilities for multi-container pods are expected to increase. They are worth considering when designing and deploying complex applications using Kubernetes.
source:- https://kubernetes.io/docs/concepts/workloads/pods/