# EUM'21 Q&A

## Mon Jan 25th

Before entering a question, copy the Q/A lines and add a new set.

### ReFrame

#### Q: For programs with nondeterministic tests, I presume there is a way to say: assert(answer == 5, within 2) or something so it would pass at 3,4,5,6,7?
*(by Bennet)*

A: Yes, via `assert_bound`.

#### Q: How to handle applications with varying output format (like a funny quote at the end)?

A: You can use regular expressions to grab the thing you care about from the generated output, via Python code.

#### Q: To what extent have you seen

#### Q: What mechanisms does it have to check more complex results, e.g. VTK? Should I again write a "checker" function?
*(by Gerasimo)*

A: *(will ask during tutorial)*

### CernVM-FS

#### Q: Can you elaborate a bit on the problems you have seen with getting HPC sites to adopt to making CernVM-FS repositories available on their system? What type of concerns are typically raised, and are they valid?
*(by Kenneth)*

A:
* Dealing with lack of outgoing network connectivity, tools are provided bu requires extra work
* Providing FUSE client, some sites do not like doing it
* Some tools have been implemented to make things easier.
* Lack of local disk on compute node => no CernVM-FS local cache possible. Can be fixed via RAMdisk, etc.

#### Q: Loading CernVM-FS cache seems to trigger quite a bit of load, which may cause jitter and affect scalability.
*(Alan)*

A:

#### Q: How much effort will be put into supporting CernVM-FS on different operating systems?
*(Victor)*

A: Service container is fallback option in case OS is not supported.
CernVM-FS is low-level enough that proper packages for OS is a strong requirement, so the project will need to deal with it.

#### Q: Can CernVM-FS be used to mount different repositories at the same time (for example for bioinfo data stuff)?
*(Erich)*

A: Yes, each repository can be used independently, and caching can be configured to be shared or separate.

### EasyBuild State of the Union

#### Q:

A: