EX316 exam objectives

[jnmalledo]

Hi,

I've just finished the DO316 course and I'm preparing to get the certification through the EX316 exam. While reading course objectives, I found this one in particular:

"Connect virtual machines to external storage using Multus"

I'm having problems finding documentation that links "multus" with "storage". During the course we were instructed to create external PV resources (nfs/iSCSI) using external IPs, is that what they refer as "multus storage"? If this is not the case, is there any documentation I can look at regarding to this issue?

Thank you

[Natalie_Lind · Accepted solution]

I can't speak to the exam, but I can convey what the course meant about that objective.

You're on the right track with Multus and IPs to connect to external storage. You use a Network Attachment Definition, which calls on the Multus CNI plug-in to chain other CNI plug-ins (ex: Linux bridge), to connect your VM to networks that are external to the OpenShift cluster. After your VM is connected to this external network, your VM can then connect to storage resources that exist on that network. You can do this through a PV, which keeps the connection as a Kubernetes object (great for a DevOps/GitOps approach), or map to the networked storage directly inside the VM through features in the guest operating system.

So for this course objective, you use Multus (through a Network Attachment Definition) to connect a VM to a network where a storage resource resides and then connect the VM to that storage, either through a PV or inside the VM itself.

I hope this helps!