By: Veerendra Prasad K S, Senior Technical Architect, LTIMindtree

1. Cloud Computing on Containers?

Containers are a good option for managing and deploying software in the cloud. They are used to conceptualize applications from the physical environment in which they are operating. Container files all dependencies related to a software element and runs them in a remote environment.

Normally running the Docker container engine, applications install constantly in any environment, whether a public cloud, a private cloud, or a bare metal machine. Products containerized are simpler to migrate. It is also making it easier to leverage the massive automation abilities of the cloud. Containers can easily be fitted, replicated, or altered using APIs provided by the container engine.

2. Containers Use Cases on Cloud

Containers are becoming gradually more important in cloud ecosystems. Various companies are considering containers as an option to Virtual Machines (VMs), earlier by tradition the preferred option for large-scale enterprise workloads.

The subsequent use cases are especially suitable for running containers in the cloud:

• Microservices: the containers are exceptionally light, producing them well suited for applications with microservices architectures comprising of many loosely coupled, individually deployable services.
• DevOps: several DevOps teams build applications using a microservices structural design and implement services using containers. They can also be used to install and gauge the DevOps infrastructure itself, such as CI/CD tools.
• Hybrid and Multi-Cloud: for businesses operating in two or more cloud environments, containers are extremely useful for migrating workloads. They are a dependable unit that can be compliantly moved between on-premises data centers and any public cloud.
• Modernization: application modernization is a traditional way to modernize a legacy application to containerize it, and change it as is to the cloud (“lift and shift”).

3. Cloud Containers Work

Container technology commenced with the division of partitions and chroot practices, launched as a part of Linux. Current container engines take the form of application containerization (Docker) and system containerization (Linux containers).

They depend on isolation, controlled at the operating system kernel level, to deploy and run applications. They use the operating system kernel and do not need to run a complete operating system—they only need to run the required files, libraries, and configuration to run workloads. The present operating system limits the container’s ability to consume physical resources.

Usually in cloud, a general pattern is to use containers to run an application instance. This can be a separate microservice, or a backend application such as a database or middleware component. They make it possible to run multiple applications on the same cloud VM, while ensuring that challenges with one container do not affect other containers or the entire VM.

Cloud providers offer several types of services you can use to run containers in the cloud:

• Container Hosted— lets you run containers directly on public cloud infrastructure, without the agent of a cloud VM. A good example is Azure Container Instances.
• Containers as a Service (CaaS)— runs containers at scale, typically with limited orchestration capabilities. A good example is Amazon Elastic Container Service or Amazon Fargate.
• Kubernetes as a Service (KaaS)— offers Kubernetes, the most widely held container orchestrator, as a managed service. Let’s you deploy clusters of containers on the public cloud. A notable example is Google Kubernetes Engine (GKE).

4. Containers and Virtual Machines on Cloud Environment

In many cloud computing environments, the basic unit used to deploy workloads is a virtual machine (VM). Like containers, virtual machines (VMs) are independent computing ecosystems abstracted from the hardware. Unlike containers, virtual machines require a full copy of the operating system to run.

Virtual machines can be used to run guest operating systems different from the host system, so if the host is running Windows, the VM can run Linux, or any other OS. In many technical scenarios, virtual machines provide improved isolation and security compared to containers.
Though a VM is a separate machine with its own operating system, it takes a lot longer to start up and run than a container. Virtual machines images that are used to create new VMs are heavier than container images and more difficult to automate.

In cloud, the most common scenario is running containers on top of compute instances, which are technically VMs. Cloud providers are now proposing the ability to run containers directly on their bare metal servers, without VMs as a mediator – a model known as “container instances.”

5. Associating Containers and the Cloud: Challenges and Solutions

Migration

Containers can drastically reduce costs, but in traditional computing environments, it can be difficult to transition  existing applications to containers. In many companies, IT staff does not have container experience and needs to be trained or assisted by consultants. Cloud computing on its own raises technical challenges for many operations teams, and containers may add another level of complexity.

Same with  any technology shift, organizations and technical teams must adapt to cloud native technology. The container ecosystem offers a variety of tools that can make adoption easier, including managed services that give emphasis to swift onboarding and ease of use.

6. Security for Container

Native cloud providers use a common responsibility model, where the cloud provider is responsible for securing the underlying infrastructure, and customers are responsible for correctly configuring security controls, to secure their workloads and data.
When containers are concerned, the cloud provider assumes responsibility for the underlying container hosts and the hypervisor, even though containers themselves and the persistent storage volumes they use must be secured by your organization. Securing containers includes several aspects:

• Container images can comprise vulnerable software components or malware.
• Default configuration of container engines like Docker provides wide privileges. Attackers can leverage the common kernel to infect other containers, and the host operating system if containers are not appropriately locked down.
• Containers are short-lived, making it harder to keep track of them, monitor them, and identify security concerns.
  Security is vital during the entire lifecycle of a container. Scan container images to make sure they are safe, use configuration best practices to lock down containers and eliminate unnecessary privileges, and restrict access and network traffic to a minimum. Ultimately, keep track of running containers using monitoring and security tools that support containerized environments.

7. Networking in Container

Container networks can be extremely complex, and this complexity can also lead to security issues. In a containerized environment, you cannot use conventional networking techniques. Container networking uses guidelines like Container Network Interface (CNI) and is managed using overlay networks—these create isolated, private networks for communication between containers and hosts.

On cloud, things get even more complicated, because cloud providers offer their own terminology for networking, such as virtual private clouds (VPC) and security groups to control access. When running separate containers on the cloud, you will need to manage their networking and make sure it supports private networks you have set up within the public cloud. If you get things wrong, you can end up revealing containers to the public Internet.

Many companies solve these matters by using managed container services, or adopting orchestrators like Kubernetes or Nomad, which have built-in networking management for clusters of containers.