305-300 Exam Dumps : LPIC-3: Virtualization and Containerization - Exam 305, version 3.0

The WORKDIR instruction sets the working directory for any subsequent RUN, CMD, ENTRYPOINT, COPY and ADD instructions that follow it in the Dockerfile1. The RUN instruction executes commands in a new layer on top of the current image and commits the results2. The RUN cd command does not change the working directory for the next RUN instruction, because each RUN command runs in a new shell and a new environment3. Therefore, the file test is created in the root directory (/) of the container image, not in the /tmp directory. References:

Dockerfile reference: WORKDIR

Dockerfile reference: RUN

difference between RUN cd and WORKDIR in Dockerfile

 LXD supports the following network interface types for containers: macvlan, bridged, physical, sriov, and ovn1. Macvlan creates a virtual interface on the host that is connected to the same network as the parent interface2. Bridged connects the container to a network bridge that acts as a virtual switch3. Physical attaches the container to a physical network interface on the host2. Ipsec and wifi are not valid network interface types for LXD containers. References:

1: Bridge network - Canonical LXD documentation

2: How to create a network - Canonical LXD documentation

4: LXD containers and networking with static IP - Super User

The lxc-attach command allows the user to start a new process within a running LXC container12. It takes the name of the container as an argument and optionally a command to execute inside the container. If no command is specified, it creates a new shell inside the container1. For example, to list all the files in the home directory of a container named myContainer, one can use:

lxc-attach -n myContainer – ls -lh /home

References:

1: Executing a command inside a running LXC - Unix & Linux Stack Exchange