Deploying applications in a container decouples parts of
the application. Consider a traditional application stack
like LAMP (Linux, Apache, MySQL, Perl/Python/PHP).
This was the foundation for many websites over the
years. To deploy a LAMP stack in a virtual environment,
you load an operating system and application on top of a
hypervisor and then repeat this process for however
many virtual machines you need to support the number
of users you expect. Include a load balancer in front of
these virtual machines, and you can add capacity as
needed. The problem with this design is that the virtual
machines run full operating systems, replicated a
number of times. You also have to maintain the virtual
machines the same as you would as if they were physical
servers. Capacity is handled manually, and you can easily
run out of resources if your website receives more
visitors than you planned for. Figure 13-11 shows a
LAMP deployment on virtual machines.
Figure 13-11 LAMP Stack on a Virtual Machine
Infrastructure
Now consider what happens if you deploy that same
application stack in a container infrastructure. You
decouple the components of the stack and deploy them