Privileged containers are a type of container that has additional access privileges to the underlying host system. In simple terms, it means that privileged containers have more access to system resources and capabilities than regular containers.
Why Use Privileged Containers?
Privileged containers are useful when you need to run specific applications that require access to system-level resources that are not available to regular containers. These applications could be hardware drivers, security tools, or network monitoring tools that require kernel-level access.
How Privileged Containers Work?
By default, containers are not allowed access to the host system's resources, such as changing the host's network settings or accessing hardware devices. But with privileged containers, the container has elevated privileges compared to regular containers. In other words, privileged containers can do things that regular containers cannot.
Example of Privileged Containers
Let's take an example of a container that needs to access a network adapter directly on the host system. Without privileged access, the container would not be able to access the network adapter. But with privileged access, the container can access the network adapter, configure network settings, etc.
Here is an example of a Dockerfile that can be built to run a privileged container:
FROM ubuntu RUN apt-get update && apt-get install -y iproute2
CMD ip link set eth0 up && tail -f /dev/null
In this example, we have installed iproute2 package in the base Ubuntu image and started the container with the CMD command to set up the Ethernet interface.
Conclusion
Privileged containers are a powerful tool for specific use cases, where more access to system resources is needed. However, it is important to use them with caution and only when necessary. Understanding privileged containers can help in making informed decisions about their usage.