Increase systemd service process limit

[peterfab9845]

resolvconf ends up calling itself several times due to subscriber scripts and may go over 10 processes, resulting in the below message and ultimately an empty resolv.conf:

/bin/resolvconf: fork: retry: Resource temporarily unavailable

[flichtenheld]

Hmm, I wonder whether it makes sense to increase this value or whether we should just remove it entirely. It is clearly a value that depends very much on the individual setup, especially which user openvpn is running under. 10 is probably a value that was chosen to be "high enough that it doesn't usually cause problems". To be fair, I haven't seen any other reports about this, so in most cases it seems indeed to work fine. (at least in older versions)

[peterfab9845]

In my case, openvpn is the only thing running under its user. However, if the decision is to increase rather than remove the limit, I suspect it should be TasksMax=N (limited per service) rather than LimitNPROC=N (per user, as you mentioned).

[flichtenheld]

We have #929 now so clearly there is some interest in getting this default changed.