Container Implementation: 9 Key Factors That Need Attention!
Containerization is no doubt a technology evolution that has been effective in addressing the application delivery concerns across organizations.
Containers are known for their lightweight architecture, immutable nature in delivering apps, high-speed initiation and executing abilities.
While containers are most commonly termed as ‘advancement to Virtual Machines (VM)’, that’s not enough to start off with applying them.
Effective implementation of containers demands a fresh mindset and better understanding of its key principles.
Here are 9 important factors that you should pay special attention to in dealing with container services:
1) Data Storage
Data storage in containers doesn’t work the way it does in traditional processes. Since the containers are flexible to updating, delete or replace functions, any irregularities or improper data storage planning can lead to loss of critical data. To avoid such concerns, experts recommend to store data in a volume while dealing with containers.
Even in that case, make sure no two containers write data on the same volume to avoid data corruption. Shared data storage is the ideal option!
2) Create Smaller Images
Containers only carry files and library resources specific to individual applications/processes. So, installing any unnecessary packages or larger images that demand additional files can abrupt the core ability of container services in generating distributed applications.
3) Application Deployment
Owing to a few similarities with Virtual Machines, people tend to take application deployment in containers similar to the deployment in VMs. Application deployment in containerization cannot take place on running containers. That might work in the development phase involving continuous deployment and debug operations. But for the continuous delivery pipeline involving QA and production, application should be part of images.
4) Layered Filesystem
To make the effective usage of layered file system in containerization, make use of different layers instead of using a single layer image. Create a base image layer for OS and individual layers for username definition, runtime installation, configuration and for application. This makes it easier to recreate, manage and distribute images.
5) Creating Images
Experts recommend not to use ‘docker commit’ for creating container images, owing to its limitations in generating images with reproducible ability. Instead, Dockerfile or any other source-to-image approach is highly recommendable. Storing images in a source control repository like Git allows you to track changes to Dockerfile.
6) Usage of Tags
Layered filesystem nature of containers allows usage of tags. However, the ‘Latest’ tag, similar to ‘Snapshot’ in Maven, is strictly not recommendable in containers. It does not mean latest and is just a tag applied to a container image by default. Usage of this tag can lead to misunderstanding within functionality and result in the retrieval of a wrong ‘latest’ version from the build cache.
This can also create a confusion when a new version that is backward incompatible replaces parent layer, making application disfunction.
7) Multiple Processes
Files and resources in every container package are limited only to the specific microservice that container is intended for. Because of this reason, containers are best suitable for running single process (application server or database or any other) Running more one process makes it difficult to manage, retrieve logs and update processes, individually.
8) Environment Variables
In a container environment, it’s not recommendable to store credentials like username and password in a container image. Instead, try to retrieve them from outside the container through environment variables.
9) IP Address
It’s not suggestible to rely on IP addresses much in containers, as every container has its own IP address that changes for every start or stop instance. This becomes a problem if an application or a microservice wants to communicate with other container on board. Instead, environment variables can be the best way to pass proper hostname and switch between containers.
On an End Note
Understanding technical aspects behind is more insightful and the best way to achieve success in a specific technology.
Wait no more! Get on to make the checklist for successful implementation of technology containers in your application ecosystem.
- (Infographic) 7 Key Containerization Benefits
- (Infographic) Container Technology Services Introduction