Container Orchestration Introduction

Containers and container orchestration tools empower organizations to deliver applications and services faster, with less risk and cost, as well as scale and shrink resources based on need. Forbes cites containers and container orchestration as strategic enablers of digital transformation.

Here's how containerization works, why it's needed, and how it benefits your organization. 

Containers Overview

Containers are a type of virtualization for packaging an application with all its dependencies (such as specific versions of programming language runtimes and libraries required to run your software services) into a standardized unit.

Containers enable applications to run on any infrastructure without concern for the underlying operating system or how it is configured.

Containers solve the problem of how to deploy applications consistently across multiple environments. 

A typical enterprise containerized application has hundreds or thousands of containers. This introduces complexity if managed manually. Container orchestration removes this complexity. 

Why we need container orchestration

Container orchestration is a process and set of tools for automated deployment, configuration and management of containers.

It helps reduce manual effort, streamline workflow, and improve consistency in deployments. Containers handle tasks such as: 

• Automatically starts up the application when a new container is created
• Rolling new releases out incrementally to production
• Automatically updating monitoring, logging, and other metadata as the containers change

These automated features make container orchestration a perfect complement to automation processes for continuous integration.

How container orchestration works

When you use a container orchestration tool, such as Kubernetes, you describe the application’s configuration in the form of a configuration file known as a YAML file.

This file describes how to configure the application during deployment. Containers get created on host systems during deployment.

Once the container is running on the host, the orchestration tool manages its lifecycle according to the specifications you laid out in the container’s configuration file. 

Container orchestration features

Orchestration is a powerful concept that simplifies tasks for managing containers. These tools have many features benefiting developers and the operations teams.

The most notable features include:

Provisioning and deploying containers

Container orchestration automatically provisions and deploys containers. These steps are managed by the orchestration tool, which ensures each container has all the required resources — like CPU and memory.

Scaling

Container orchestration tools scale up the number of containers running on a host by adding more hosts to the cluster and scale down by removing hosts from the cluster. 

Load balancing

When you start up a new orchestration tool, it needs to know where to find the containers that will be load-balancing across the cluster.

This is accomplished in a couple of ways.

First, you set up a load-balancing system to expose the load-balancing endpoint for your containers and use a DNS entry to point the orchestration tool to that IP address.

Second, you set up a reverse proxy to distribute the load-balanced endpoint to the orchestration tool. 

Monitoring

Container orchestration tools are useful for performance monitoring. The tool monitors container performance metrics such as CPU utilization, memory utilization, network traffic, etc.

The data collected by the orchestration tool is used to troubleshoot when a performance problem is identified.

For example, if a container has high CPU utilization, the data collected by the tool is used to determine whether a container is consuming too much CPU or if the CPU utilization of the host is too high.

Resource allocation

Container orchestration tools allocate resources such as CPU, memory, network bandwidth, etc., as needed.

When the need for these resources changes, the orchestration tool will repartition the server’s resources accordingly. This process is called “re-balancing.”

Re-balancing allows the orchestration tool to maximize the utilization of the server’s resources. 

Security

In a cluster of hosts, there may be multiple security domains with different levels of trust. For example, a cluster may have hosts that have been verified as being in a secure data center and others that have not yet been verified.

The verification process may require collecting a host’s MAC address and IP address to be able to trace back to a physical location.

Teams may want to be able to run containers isolated from the rest of the cluster. For example, a heavy-duty SQL database.

They may also want to run containers using a higher level of trust than the rest of the cluster. For example, they may want a private Docker registry that is trusted and secure to be able to run on a cluster.

Logging

Container orchestration tools log events such as container start, stop and restart. Additional information such as the name of the application, host, IP address, port and other details are logged along with these events.

These logs are stored in a centralized log management and analysis tool. The log management tool helps in collecting, filtering, aggregating, and storing these logs.  

Kubernetes orchestration tool

Kubernetes is an open-source container orchestration tool for managing containers on one or more hosts in a cluster.

The basic architecture components of the tool are:

• Cluster: The basic unit of deployment in Kubernetes. A cluster consists of one or more nodes managed by the same master node.
• Master: Manages all nodes in the cluster. The master is configured to run any number of masters. 
• Node: A machine running Kubernetes 
• Pods: A group of one or more containers running on a node. A pod can be configured to run any number of containers.
• Kubelet: A daemon running on each node in the cluster. It is responsible for managing pods running on each node in the cluster.
• Deployment: The basic unit of deployment in Kubernetes. A deployment consists of one or more pods managed by a single kubelet.
• Scheduler: A daemon running on each node in the cluster. The scheduler is responsible for scheduling pods to run on nodes in the cluster.

Benefits of container orchestration

• Automation: Automate container deployment across environments and applications. 

• Consistency: Ensure all containers get deployed consistently across environments. 

• Scalability: Scale up or down applications without a negative impact on the environment or the application itself. 

• Security: Manage security policies for each container based on its role in the infrastructure (e.g., web server vs. database server).
  This makes it easy for developers and operations staff alike to understand what security policies are in place for each container. This helps teams to comply with those policies while also ensuring they can scale the application without a negative impact on security.
• Portability: Deploy containers across environments and applications. 

Conclusion

Container orchestration is an important part of the container ecosystem, as it helps you automate, manage, and scale your application.

Container orchestration is ideal for businesses looking to use automation to manage containers at scale. For more information on how your business can take advantage of container orchestration tools, our team of professionals will assist you.