Like any other technologies, Docker has its own advantages and disadvantages. Docker is not a silver bullet and needs care in architecting and orchestrating docker containers keeping below points in mind.
Docker is not so fast compared to bare metal servers. Even though containers are lightweight and so easy to boot up it is subjected to decreased network performance. Performance of the containers are affected as a single operating system caters to multiple containers.
Integrability : Even though Docker is open source some of the container products don’t work with all. This may be due to the competition prevailing in the market. For eg: OpenShift which is a container-as-a-service platform from Red Hat, only works with the Kubernetes.
Data loss in containers : When the container exits the data will be lost. Data could be saved through volume mounting like Docker Data Volumes but more hard work needs to be done in this space.
Poor or no GUI : Containers were used mainly for deploying server application that doesn't require GUI. There are some methods to run GUI app inside containers but it’s somewhat clumsy these days.
More suitable for applications that use microservices : Generally the docker’s benefit is to ease the application delivery by providing a packaging mechanism but the true benefit comes when we use microservices.
There are other virtualization techniques like unikernels which is based on library operating systems. Unikernels provide improved security, more optimisation and boots faster.
