Docker is an open platform for developing, shipping, and running applications. It enables developers to easily pack, ship, and run any application as a lightweight, portable, self-sufficient container which can run virtually anywhere. Docker is not a cloud but is complementary to and works very well with cloud computing platforms.
What is Docker?
Docker is a set of platform as a service products that use OS-level virtualization to deliver software in packages called containers. Containers are isolated from one another and bundle their own software, libraries and configuration files. They can communicate with each other through well-defined channels.
Docker enables developers to rapidly build, test, and deploy applications as portable, self-sufficient containers that can run virtually anywhere. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and deploy it as one package.
Some key features and benefits of Docker include:
- Portability – Docker guarantees that software running inside a container functions exactly the same, regardless of the infrastructure. This makes deployment much easier.
- Speed – Docker containers share the OS kernel and start very quickly, boosting efficiency for dev and test cycles.
- Agility – Docker’s lightweight containers foster agility and innovation as developers can quickly test ideas without waiting to provision VMs and infrastructure.
- Isolation – Docker guarantees isolation and segregation of duties among teams, applications, and microservices via completely isolated containers.
- Efficiency – Docker is very lightweight and has a small footprint, so it uses fewer resources than virtual machines which need a full OS image for every VM.
So in summary, Docker provides OS-level virtualization by delivering software in containers. This provides portability, speed, agility, isolation and efficiency benefits.
Is Docker a cloud platform?
Docker itself is not a cloud platform. Rather, Docker provides containerization functionality that enables applications to be easily portable across cloud providers and on-premises data centers.
Cloud platforms like AWS, GCP and Azure provide hosted compute, storage, networking, databases and other services. Docker does not provide any of that underlying infrastructure – rather it enables developers to easily deploy applications on whatever infrastructure they choose by packaging them into containers.
Some key differences between Docker and cloud platforms:
- Docker is containerization software for bundling and running apps in containers. Cloud platforms provide hosted infrastructure services.
- Docker gives portability across environments. Cloud ties you to a specific provider’s platform and services.
- Docker just manages containers. Cloud platforms provide full infrastructure stacks from compute to storage and services.
So in summary, Docker on its own is not a cloud platform. It provides complementary containerization functionality to enable application portability across cloud providers and on-prem infrastructure. Many cloud providers like AWS and Azure provide container services integrated with Docker.
How Docker complements cloud computing
While Docker itself is not a cloud platform, containers and Docker strongly complement and enhance cloud computing platforms like AWS, GCP and Azure in several ways:
Docker containers package up applications with their dependencies into standardized units that can run unchanged across cloud providers. This makes deployment dramatically simpler by avoiding “dependency hell”.
Docker containers run consistently regardless of the underlying infrastructure. This makes moving applications across cloud providers, or between cloud and on-prem, much easier.
Agile application lifecycles
The lightweight nature of containers enables rapid iteration of applications with minimal overhead. This aligns with the agile, continuous practices favored by many cloud-native applications.
Containers allow higher density and utilization than VMs, since multiple containers share an OS kernel. This improved efficiency can reduce cloud computing costs.
Most major cloud providers like AWS and Azure offer tight integration between their platform services and Docker containers to simplify management and deployment.
So in essence, containers and Docker strongly accelerate and simplify deployment on cloud platforms, while avoiding vendor lock-in. This makes Docker an ideal complement to enhance cloud-native development.
Common misconceptions about Docker and cloud
There are some common misconceptions about the relationship between Docker and cloud computing:
“Docker is a type of cloud platform”
This is incorrect – Docker just provides containerization capabilities, not the actual cloud infrastructure and services.
“Docker replaces cloud computing”
Docker complements cloud nicely, but still requires the actual cloud infrastructure. Docker alone doesn’t provide this infrastructure.
“Containers don’t work with cloud computing”
In fact most major cloud providers like AWS and Azure offer tight integration with Docker containers to simplify container deployment and management.
“Docker is only used for local development”
While Docker facilitates excellent local dev/test workflows, Docker containers are also commonly used in production deployments on cloud platforms.
So in summary – Docker adds portability, simplicity and velocity to deploying on cloud infrastructure, but isn’t a cloud platform by itself.
Can you run Docker without a cloud?
Yes, absolutely. While Docker pairs extremely well with cloud platforms, you do not need a cloud provider to run Docker containers.
Docker can run on-premises on bare metal servers or virtual machines in your own data center. The Docker host environment only requires Linux with kernel 3.10+ or Windows 10/Windows Server 2016.
Key options for running Docker without a cloud:
- Bare metal – Install Docker engine directly on bare metal Linux servers
- Virtual machines – Run Docker inside local VMs or VMs hosted on-premises
- Edge and IoT – Deploy containerized apps on edge devices
- Local development – Run Docker directly on developer workstations
So Docker can definitely run without any cloud provider involved, by leveraging on-prem servers, VMs, edge devices or even local development machines.
However, by pairing Docker with cloud infrastructure you get autoscaling, high availability, managed services, serverless functions and many other benefits. So a mix of on-prem Docker with public cloud resources makes a very powerful combination.
Docker alternatives vs cloud alternatives
When evaluating technology alternatives, it’s important to distinguish between alternatives to Docker itself, vs alternatives to cloud computing platforms. Docker and cloud solve different problems.
Alternatives to Docker
These provide containerization or OS-level virtualization capabilities as an alternative to Docker:
- Podman – An open-source container engine, offers many Docker-compatible functions
- LXC – Linux containers, predecessor to Docker
- OpenVZ – Container-based virtualization for Linux
- Windows Server Containers – Native container support in Windows
Alternatives to cloud computing
These alternatives provide hosted infrastructure, platforms and services instead of using a public cloud provider:
- On-premises data centers with virtualization
- Colocation facilities
- Bare metal cloud providers
- Hybrid cloud
The above alternatives provide compute, storage and other infrastructure services. Docker would typically still run on top of these alternatives to deploy containerized applications, just as it runs on top of AWS, GCP or Azure cloud.
- Docker provides containerization capabilities to package, deploy and run portable applications – it is not a cloud platform itself.
- Docker complements cloud computing extremely well for simplified deployment, increased agility and avoiding lock-in.
- Containers can run on-premises or cloud with equal facility – Docker does not require cloud to run containers.
- When evaluating alternatives, distinguish between containerization alternatives to Docker vs hosted infrastructure alternatives to replace cloud platforms.
In summary, Docker is not a cloud platform itself – rather it provides complementary containerization functionality for simplified deployment of portable applications. Docker enables lightweight, agile application lifecycles that align well with cloud-native development.
Leading cloud platforms provide tight integration with Docker to more easily deploy and manage containers. This makes Docker an ideal technology for developing applications across hybrid and multi-cloud environments while avoiding lock-in.
By decoupling applications from underlying infrastructure, Docker delivers compelling benefits for both cloud and on-premises deployment models.
Frequently Asked Questions
Q: Is Docker a PaaS?
A: No, Docker is not a PaaS (platform as a service). It provides containerization capabilities to ease deployment on various platforms.
Q: Can Docker replace a cloud platform?
A: No. Docker relies on an underlying infrastructure platform, whether cloud, virtualization or bare metal.
Q: What does Docker run on if not the cloud?
A: Docker can run on-premises directly on Linux, inside local VMs, on edge devices, developer machines and bare metal servers.
Q: Is Docker a private cloud?
A: No. Docker focuses specifically on containerization, orchestration and application management – not the actual cloud infrastructure.
Q: Can containers run in the cloud?
A: Yes, all major cloud platforms provide integrations with Docker and Kubernetes to manage container deployments.
Q: Does Docker require virtualization?
A: No. Docker provides OS-level virtualization that is more lightweight than traditional VMs.
Q: Is Docker cheaper than cloud computing?
A: Not necessarily. Docker still requires the underlying infrastructure while cloud can enable consumption-based pricing.
Q: What does Docker offer over just using VMs?
A: Major advantages like portability across environments, file and density from shared OS resources, and agile application lifecycle management.
Q: What are the security implications of Docker vs cloud?
A: Both can be secured but take different approaches – cloud security controls access to infrastructure while Docker secures host kernel access.
Q: Can Docker containers connect to cloud services?
A: Yes, applications in Docker containers can connect to database, storage, messaging and other services hosted in the cloud.
Q: Does Docker manage infrastructure?
A: No, Docker just manages containers. Infrastructure platforms like Kubernetes, OpenStack or vSphere can manage Docker hosts and infrastructure.
Q: Is Docker open source?
A: Yes, Docker debuted in 2013 as an open source containerization platform and continues to release many open source components.
Q: Can I use Docker without an internet connection?
A: Yes, Docker does not require Internet connectivity – Docker hosts can run containers while disconnected or on a private network.
Q: Is Docker Host the same as a VM?
A: No. The container host provides the environment to run Docker containers at the OS level. A VM virtualizes hardware to run multiple OS instances.
Q: Who provides enterprise support for Docker?
A: Docker Inc. and all major cloud providers offer commercial Docker support services including training, consulting and troubleshooting.
Q: Is Docker containerization or virtualization?
A: Docker provides operating system-level containerization to isolate apps from each other but share host resources. Virtualization simulates dedicated hardware.