Budric's questions

I'm trying to write a general rule to fire alert when a discovered target goes missing. In particular kubernetes pods annotated for scraping and auto-discovered using kubernetes_sd_configs.

Expressions of the form: absent(up{job="kubernetes-pods"}==1) do not return any additional labels which were available as part of the up time series. If a pod is deleted (say by mistake), it disappears as a target from prometheus. An alert based on absent() is fired, but I have no information about what pod has gone missing.

I think the same happens for auto-discovered kubernetes services. If it's deleted by mistake, it just disappears as a monitored target. I'm not sure if the behavior is the same for target_groups (https://prometheus.io/blog/2015/06/01/advanced-service-discovery/) with ip range - that is if the physical node is turned off the metrics just stop and up == 0 is not available.

What is the correct way to detect when an auto-discovered target is gone in a general way? Or do I need to hard code rules for each service/node/pod explicitly, even though it was auto discovered?

Is there a way to configure dnsmasq to hand out IPs from different range to different wireless access points?

I have a basic Asus router configured as access point (it does no routing and doesn't run dhcpd of its own) with address 192.168.10.2 and my dnsmasq (on a different server) has these lines:

dhcp-range=set:ten,192.168.10.100,192.168.10.150,12h
dhcp-range=set:guest,192.168.30.100,192.168.30.150,12h

However the clients connecting to that access point get addresses in 192.168.30.0/24 range which I don't want.

I assumed the access point broadcasts dhcp requests on 192.168.10.255 given its IP is set to 192.168.10.2 and dnsmasq would implicitly figure out to hand out the 192.168.10.0/24 range. But that's not happening.

If this configuration is not possible with dnsmasq, please suggest a different dhcp server implementation I can look into.

With Linux ACL, can you have multiple groups with default access to a folder? I want this for sharing code repositories between different coding groups + several processes. My thinking is, if a user from one group creates contents inside the shared repository, even though the owner is that user, the default permissions are propagated to that new file and the other users can still access the contents.

Here's what I tried as root:

mkdir /tmp/temp
chmod 770 /tmp/temp
setfacl -dm g:www-data:r-x,g:sambashare:r-x /tmp/temp
getfacl /tmp/temp

# file: temp
# owner: root
# group: root
user::rwx
group::rwx
other::---
default:user::rwx
default:group::rwx
default:group:www-data:r-x
default:group:sambashare:r-x
default:mask::rwx
default:other::---

As testuser

id
uid=1004(testuser) gid=1007(testuser) groups=1007(testuser),110(sambashare)
cd /tmp/temp
bash: cd: temp: Permission denied

So clearly not working as I expected. Can anyone help me understand why it's not working and how I can fix this?

P.S. I'm setting default group permissions instead of just the regular group permission because those are supposed to propagate to children.

 setfacl -m g:sambashare:r-x /tmp/temp

Thanks.