Hey there! With container adoption growing rapidly, you might be wondering – what is all the hype about and should you be using containers? By the end of this guide, you‘ll understand what containers are, their benefits, and why they are becoming so popular for deploying cloud-native applications. Let‘s get started!
What is Containerization?
In simple terms, containerization refers to bundling an application together with all its dependencies like libraries, binaries, and configuration files into a standardized unit called a container image.
This container image contains everything the application needs to run – the code, runtimes, tools, libraries, and settings. The image acts like a lightweight, portable capsule that can be quickly spun up on any infrastructure that supports containers.
This means you can build an application once and run it anywhere – on your laptop, data center, cloud etc. Containers ensure the application executes reliably and consistently across different environments.
Containers vs Virtual Machines
Containers may seem similar to virtual machines (VMs) at first glance. But under the hood, containers and VMs work very differently:
As you can see in the diagram above:
- VMs virtualize at the hardware layer and run multiple guest OS instances on a single physical server.
- Containers virtualize at the OS layer, allowing multiple isolated user-space instances to share the same kernel.
This means containers provide faster startup times and lower overhead. A 2019 study found containers use 50% – 70% fewer resources than VMs.
How Do Containers Work?
Under the hood, containers rely on Linux namespaces and control groups (cgroups) to provide isolation for processes, memory, CPU, network, and the filesystem.
Namespaces ensure that each container has a dedicated view of the underlying infrastructure like process IDs, network interfaces, filesystem mounts etc. Control groups limit and allocate resources like CPU time, memory usage, disk I/O for each container.
Together, namespaces and cgroups allow each container to run in isolation with its own dependencies while safely sharing the host kernel. Pretty cool!
Anatomy of a Container
A container image consists of multiple layers stacked on top of each other to create the final filesystem:
The lowest layer is the boot filesystem extracted from the base OS image. On top of this, you have layers for dependencies, libraries, binaries, and any filesystem changes.
The topmost layer stores environment variables, arguments, and the default command to run. All these layers are stacked together into one unified container image that you can instantiate using a container runtime.
Container Management 101
To start running containers in production, you need container management platforms that help with deployment, scaling, load balancing, scheduling etc.
Popular options include:
- Kubernetes: The de facto orchestration choice and a cloud native standard. Automates deployments, scaling, networking for container clusters.
- Docker Swarm: Docker‘s native clustering and scheduling tool. Simpler but less robust than Kubernetes.
- Apache Mesos: Abstracts CPU, memory, storage and offers resource isolation and sharing across data centers.
- HashiCorp Nomad: Focuses on cluster utilization and efficient task placement for high-performance computing workloads.
Choosing the right container management platform depends on your application architecture, environment, and scalability needs.
Why are Containers Gaining Popularity?
Here are some key reasons why Docker and other container technologies are seeing massive adoption:
- Portability – Container images run consistently across any infrastructure. Build once, run anywhere.
- Speed – Containers provide faster startup times than VMs. New instances can spawn in seconds.
- Agility – The lightweight nature of containers allows for rapid iteration of apps. Easy to build, share and deploy.
- Isolation – Containers safely isolate apps and their dependencies into self-contained units. Improves security.
- Scalability – You can easily scale applications up and down by launching more containers.
- Resource Efficiency – Containers allow you to get greater density and utilization compared to VMs.
According to recent forecasts by Allied Market Research, the global container market size will grow at a CAGR of 28% from $2.1 billion in 2020 to $8.6 billion by 2027. The future is certainly containerized!
Containerization Use Cases
Some common examples of how leading organizations leverage containerization:
- Netflix containerizes each tier of their streaming service separately for improved availability and scalability.
- Dropbox migrated their entire infrastructure from VMs to containers, reducing resource usage by 50% while doubling the number of users.
- Spotify uses Docker containers to package and run their microservices architecture with over 1200 internal services.
- Amazon runs services like Amazon Relational Database Service using containers for flexibility across on-premise, AWS cloud, and edge locations.
Best Practices for Container Security
Since containers share an OS kernel, hardening your environment is crucial:
- Use vetted base images from trusted repositories like Ubuntu, RedHat etc. Avoid untrusted public images.
- Scan images for known vulnerabilities using tools like Trivy, Anchore or Qualys.
- Limit container capabilities via read-only filesystems, SELinux, AppArmor, seccomp profiles.
- Restrict container-to-host access using forwarded ports instead of the Docker socket.
- Continuously monitor running containers for suspicious activity and anomalous behavior.
Adopting these practices will help boost the security posture for your container workloads.
Looking Ahead to 2023
We are only scratching the surface of what containerization enables! Here are two major trends to expect in 2023:
- Serverless platforms like AWS Lambda, Azure Functions, and Cloud Run will increasingly adopt container packaging for simplified deployment of microservices.
- As edge computing gains traction, containers will emerge as the optimal approach to deploy apps consistently across fragmented edge environments.
If you aren‘t leveraging containers for your cloud-native applications yet, 2023 might just be the year to get started! Reach out if you need any help. Chat soon!