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Four keys to designing Docker applications

Docker has become ubiquitous in container technology. Designing applications with portability in mind can help enterprises take advantage of all the container technology has to offer.

With the increasing popularity of Docker applications and containers, many businesses are looking at container technologies as the basis for their cloud operating system and application packaging. Businesses are choosing container systems over VMs because containers provide scalability, portability and efficiency. Unlike VMs, multiple containers can run on the same kernel of the host OS, resulting in less overhead and better performance.

Docker provides an environment for applications inside containers, which are portable between platforms. Docker is a popular choice because it eases application deployment and management. Because of its open source design, developers can contribute features specific to their businesses' unique needs. One advantage of Docker is that it's a widely used container management system; therefore, numerous support resources are available.

To optimize your application designs for Docker and containers, follow these four tips.

Think about your business and app goals

A container is a midpoint between dedicated servers and VMs. It offers more isolation than an operating system (OS) but less than a VM. Determine your goals for using containers and what you expect to get from them. The answer will frame how you design your Docker applications.

Docker provides an environment for applications inside containers, which are portable between platforms. Docker is a popular choice because it eases application deployment and management.

The best justification for container use is the ability to build a private cloud that is hybridized with public cloud services. Containers help unify a hybrid cloud in terms of operations practices; hybrid containers work best when there is a common OS platform. Because all containers operate on the same kernel, make sure the OS is consistent to prevent incompatibility. Use middleware services for container applications that match your OS version. If you run Docker applications on different OSes, treat them as independent Docker communities.

Adopt a collective mind-set

Docker works to its full potential if an application and its related components are built, moved and scaled in unison on the same server. By packaging the application and components together in one application specific container, you'll take advantage of one of Docker's strengths.

The key to packing an application with the needed components is to understand component workflows. Find natural groupings of components by following the trail of work among the components and identify where most exchanges occur.

Know your name

Docker gives each container its own namespace and file system. Make sure other processes can access this functionality and shared data. Network connectivity is one aspect of this, but another is controlling all your application directories, including a domain name system (DNS).

Think of these collected components and microservices as an independent subnetwork, like a set of servers hosting what's now a Docker container. You'd have to manage the URLs representing these servers, and you'll have to do the same with Docker containers. If you use Docker with SOA/SOAP, ensure service directories are updated when deploying or moving containers and collections.

Make a connection

Cloud containers are integrated with each other and often with noncontainerized application elements. Docker does a lot to manage container deployment but far less to manage workflow integration. When choosing to work with containers, find out what is offered and make sure it meets your requirements. The most common problem new Docker users report is an inability to access the Internet or the company network from Docker applications. Docker can facilitate wide-area connectivity but you will have to make the connections.

Docker can really be helpful for ensuring container compatibility. Unfortunately, there is no guarantee of compatibility when integrating workflows across cloud containers. Most workflows are integrated through a directory function, like a DNS. Be sure the directory is updated when you deploy or move a container.

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