As we have discussed previously on our blog the importance of switching to a DevOps way of software development, we now shift the conversation to containerization, which is a popular technology that is increasingly being used to make the implementation of DevOps smoother and easier. As we know, DevOps is a cultural practice of bringing together the ‘development’ and the ‘operation’ verticals so that both the teams work collaboratively instead of in siloes, whereas containerization is a technology that makes it easier to follow the DevOps practice. But what exactly is containerization? Let’s find out!
What is Containerization?
Containerization is the process of packaging an application along with its required libraries, frameworks, and configuration files together so that it can be run in various computing environments efficiently. In simpler terms, containerization is the encapsulation of an application and its required environment.
It has lately been gaining lots of traction as it overcomes the challenges that stem from running virtual machines. A virtual machine emulates an entire operating system inside the host operating system and requires a fixed percentage of hardware allocation that goes into running all the processes of an operating system. And this, therefore, leads to unnecessary wastage of computing resources due to large overhead.
Also, setting up a virtual machine takes time, and so does the process of setting up a particular application in each and every virtual machine. This results in a significant amount of time and effort being taken up in just setting up the environment. Containerization, popularized by the open-source project ‘Docker’, circumvents these problems and provides increased portability by packaging all the required dependencies in a portable image file along with the software.
Let us dive deeper into containerization, its benefits, how it works, ways of choosing the tool for containerization and how it trumps the usage of virtual machines (VMs).
Some popular container providers are:
- Linux Containers like LXC and LCD
- Windows Server Containers
What is Docker?
Docker has become a popular term in the IT industry, and rightly so. Docker can be defined as an open-source software platform which offers a simplified way of building, testing, securing, and deploying applications within containers. Docker encourages software developers to collaborate with cloud, Linux, and Windows operating systems for easy and faster delivery of services.
Docker is a platform that provides containerization. It allows for packaging of an application and its dependencies into a container, thereby, helping ease the development and accelerate the deployment of the software. It helps maximize output by doing away with the need to replicate the local environment on each machine on which the solution is supposed to be tested, thus saving valuable time and effort that would go into the furthering of the progress.
Docker file can be quickly transferred and tested among the workers. The process of container image management is also made simple by Docker and is quickly revolutionizing the way we develop and test applications at scale.
Containerization – Implementing DevOps
Let’s find out why containers are slowly becoming an integral part of the standard DevOps architecture.
Docker has popularized the concept of containerization. Applications in Docker containers have the capability of being able to run on multiple operating systems and cloud environments such as Amazon ECS and many more. Hence, there is no technology or vendor lock-in.
Let us understand the need for implementing DevOps with containerization.
Initially, software development, testing, deployment, and the supervising required were undertaken one after another in phases, where completion of one phase would lead to the beginning of another.
DevOps and Docker image management technologies, like AWS ECR, have made it easy for software developers to perform IT operations, share software, and collaborate with each other, and enhance productivity. Apart from encouraging developers to work together, they are successful in eliminating the conflict of different work environments that affected the application previously. To put it simply, containers, being dynamic in nature, allow IT professionals to build, test, and deploy pipelines without any complexities while, at the same time, bridging the gap between infrastructure and operating system distributions, which sums up the DevOps culture.
Software developers are benefited by containers in the following ways:
- The environment of the container can be changed for better production deployment.
- Quick startup and easy access to operating system resources.
- Provides enough space for more than one application to fit in a machine, unlike traditional systems.
- It provides agility to DevOps, which can help in switching between multiple frameworks easily.
- Helps in running working processes more efficiently.
Elucidated below are the steps to be followed to implement containerization successfully using Docker:
- The developer should make sure the code is in the repository, like the Docker Hub.
- The code should be compiled properly.
- Ensure proper packaging.
- Make sure that all the plugin requirements and dependencies are met.
- Create Container images using Docker.
- Shift it to any environment of your choice.
- For easy deployment, use clouds like Rackspace or AWS or Azure.
Benefits of using Containers
A number of companies are opting for containerization for the various number of benefits it entails. Here’s a list of advantages you will enjoy by using containerization technology:
Containerization packages the application along with its environmental dependencies, which ensures that an application developed in one environment works in another. This helps developers and testers work collaboratively on the application, which is exactly what DevOps culture is all about.
2. Multiple Cloud Platform
Conatiners can be run on multiple cloud platforms like GCS, Amazon ECS (Elastic Container Service), Amazon DevOps Server.
3. Portable in Nature
Containers offer easy portability. A container image can be deployed to a new system easily, which can then be shared in the form of a file.
4. Faster Scalability
As environments are packaged into isolated containers, they can be scaled up faster, which is extremely helpful for a distributed application.
5. No Separate OS Needed
In the VM system, the bare-metal server has a different host OS from the VM. On the contrary, in containers, the Docker image can utilize the kernel of the host OS of the bare-metal physical server. Therefore, containers are comparatively more work-efficient than VMs.
6. Maximum Utilization of Resources
Containerization makes maximum utilization of computing resources like memory and CPU, and utilize far fewer resources than VMs.
7. Fast-Spinning of Apps
With the quick spinning of apps, the delivery takes place in less time, making the platform convenient for performing more development of systems. The machine does not need to restart to change resources.
With the help of automated scaling of containers, CPU usage and machine memory optimization can be done taking the current load into consideration. And unlike the scaling of Virtual Machines, the machine does not need to be restarted to modify the resource limit.
8. Simplified Security Updates
As containers provide process isolation, maintaining the security of applications becomes a lot more convenient to handle.
9. Value for Money
Containerization is advantageous in terms of supporting multiple containers on a singular infrastructure. So, despite investing in tools, CPU, memory, and storage, it is still a cost-effective solution for many enterprises.
A complete DevOps workflow, with containers implemented, can be advantageous for the software development team in the following ways:
- Offers automation of tests in every little step to detect errors, so there are fewer chances of defects in the end product.
- Faster and more convenient delivery of features and changes.
- Nature of the software is more user-friendly than VM-based solutions.
- Reliable and changeable environment.
- Promotes collaboration and transparency among the team members.
- Cost-efficient in nature.
- Ensures proper utilization of resources and limits wastage.
Difference Between Containers and Virtual Machines (VMs)
A Virtual Machine has the capability to run more than one instance of multiple OS’s on a host machine without overlapping. The host system allows the guest OS to run as a single entity. A docker container does not burden the system as much as a virtual machine, as running an OS requires extra resources, which can reduce the efficiency of the machine.
Docker containers do not tax the system and use only the minimum amount of resources required to run the solution without the need to emulate an entire OS. Since fewer resources are required to run the Docker application, it can allow for a larger number of applications to run on the same hardware, thereby cutting costs.
However, it reduces the isolation that VMs provide. It also increases homogeneity because if an application runs on Docker on one system, then it will run without any hiccups on Docker on other systems as well.
Both containers and VMs have the virtualization mechanism. But for containers, the virtualization of the Operating System takes place; while in the latter, the virtualization of the hardware takes place.
VMs show limited performance, while the compact and dynamic containers with Docker show advanced performance.
VMs require more memory, and therefore have more overhead, making them computationally heavy as compared to Docker containers.
Some of the commonly-used Docker terminologies are as followed:
- Dependencies – Contains the libraries, frameworks, and software required to form the environment, which can emulate the medium that executes the application.
- Container image – A package that provides all the dependencies and information one needs to create a container.
- Docker Hub – A public image-hosting registry where you can upload images and work on them.
- Dockerfile – A text file containing instructions on how to build a Docker image.
- Repository – A network-based or internet-based service that stores Docker images. There are both private and public Docker repositories.
- Registry – A service that stores repositories from multiple sources. It can be both public as well as private.
- Compose – A tool that aids in the defining and running of multiple container Docker applications.
- Docker Swarm – A cluster of machines created to run Docker.
- Azure Container Registry – A registry provider for storing Docker images.
- Orchestrator – A tool that helps in simplifying the management of clusters and Docker hosts.
- Docker Community Edition (CE) – Tools that offer development environment for Linux and Windows Containers.
- Docker Enterprise Edition (EE) – Another set of tools for Linux and Windows development.
Docker Containers, Images, and Registries
A service is created with Docker, and then it is packaged into a container image. A Docker image is a virtual representation of the service and its dependencies.
An instance of the image is used to create a container which is made to run on the Docker host. The image is then stored in a registry. A registry is needed for deployment to production orchestrators. Docker Hub is used to store it in its public registry at a framework level. An image, along with its dependencies, is then deployed into one’s choice of environment. It is important to note that some companies also offer private registries.
A business organisation can also create their own private registry to store Docker images. Private registries are provided if images are confidential and the organisation wants limited latency between an image and the environment where it is deployed.
How does Docker perform Containerisation?
Docker image containers or applications can run locally on Windows and Linux. This is achieved simply by the Docker engine interfacing with the operating system directly, making use of the system’s resources.
For managing clustering and composition, Docker provides Docker Compose, which aids in running multiple container applications without overlapping each other. Developers further connect all the Docker hosts to a single virtual host through the Docker Swarm Mode. After this, the Docker Swarm is used to scale the applications to a number of hosts.
Thanks to Docker Containers, developers have access to the components of a container, like application and dependencies. The developers also own the framework of the application. Multiple containers on a singular platform, and depending on each other, are called Deployment Manifest. In the meantime, however, the professionals can pay more attention to choosing the right environment for deploying, scaling, and monitoring. Docker helps in limiting the chances of errors, that can possibly occur during transferring of applications.
After the completion of the local deployment, they are further sent to code repository like Git repository. The Docker file in the code repository is used to build Continuous Integration (CI) pipelines that extract the base container images and build Docker images.
In the DevOps mechanism, the developers work on the transferring of files to multiple environments, while the managerial professionals look after the environment to check defects and send feedback to the developers.
Future-Proofing Containerization Strategy
It is always a good idea to anticipate the future and prepare for scalability post deciding upon the requirements of a project. With time, the project gets more complex, and therefore, it is necessary to implement large scale automation and offer faster delivery.
Containerized environments, being dense and complex, require proper handling. In this context, PaaS solutions can be adopted by software developers to focus more on coding. There are multiple choices when it comes to selecting the most convenient platform that offers better and advanced services. Hence, determining the right platform for an organization based on its application is quite taxing.
To make it easy for you, we’ve laid down some of the parameters to be considered before choosing the best platform for containerization:
1. Flexible in Nature
For smooth performance, it is important to hand-pick a platform which can be adjusted or altered easily and automated depending on the nature of the requirements.
2. Level of Lock-In
Being mostly proprietary in nature, PaaS solution vendors have the tendency to lock you into one infrastructure.
3. Room for Innovation
Choose a platform that has a wide range of in-built tools along with third-party integrated technologies for encouraging the developer to make way for further innovation.
4. Cloud Support Options
While choosing the right platform, it is crucial to find one which supports private, public, and hybrid cloud deployments, to cope with the new changes.
5. Pricing Model
As it is natural to pick a containerization platform that can support long-term commitments, it is important to know what pricing model is offered. There are plenty of platforms that offer different pricing models at different scales of operations.
6. Time and Effort
Another crucial aspect to keep in mind is that containerization does not happen overnight. The professionals need to invest their time in restructuring the architectural infrastructure. They should be encouraged to run micro-services.
To shift from the traditional structure, large applications need to be broken down into small parts which are further distributed into multiple connected containers. It is recommended, therefore, to hire experts who can put in the required efforts towards finding a convenient solution to handle both Virtual Machines and containers on a singular platform, as making an organisation completely dependent on containers takes time.
7. Inclusion of Legacy Apps
When it comes to modernization, legacy IT apps should not be ignored. With the help of containerization, IT professionals can reap the benefits of these classic apps for proper utilization of investment in legacy frameworks.
8. Multiple Application Management
Make the most of containerization by running more than one application on container platforms. Invest in new applications at minimal cost and modify each platform by making it friendly for both current as well as legacy apps.
As a containerized environment has the capability to change quicker than the traditional environment, it has some major security risks. The agility can benefit the developers by offering fast access. However, it will fail in its task if the required level of security is not ensured.
A major one, encountered while dealing with containers, is that handling container templates packaged by third-party or untrusted sources can be very risky. It’s, therefore, better to verify a publicly available template before using it.
An organisation needs to enhance and integrate its security processes for the hassle-free development and delivery of apps and services. With the modernization of platforms and applications, security should be a major priority for an enterprise.
To keep pace with the ever-changing IT industry, the professionals should keep on striving for better, and therefore, utilize new tools available in the market to enhance security.
Our experts at Maruti Techlabs have successfully migrated complex application architectures to containerized micro-services. We strategically plan and implement containerization in stages and measure the outcome of each step taken. Our DevOps experts also help you make an organizational shift to the DevOps culture in a phase-wise manner. We help you through each step of the transformative journey to ensure your business scales new heights in the long run. Simply drop us a note here for your end-to-end DevOps or application migration needs.