A. Trevelyan's questions

Prefacing this by saying I'm not a storage expert.

I have a storage array that I want to connect to a physical linux host running Ubuntu 18.04.06. The server has a 4-port SAS HBA, and the storage array is a dual-controller unit, each with 4 SAS ports per controller. The storage array is a Dell Powervault ME4024, and the server is a Dell Poweredge R640.

Here's a diagram for a quick explanation of how everything is connected:

The reason for the dual connection is because I was advised to do it like this since storage errors are very difficult to recover from, and this way accounts for things like one cable becoming disconnected for whatever reason, or a controller failure or something like that.

The array is small right now, but has a lot of empty drive bays I want to use to expand the storage later. For right now, there are 2 900GB drives installed in a RAID1 disk group:

The server appears to be seeing the storage from each connection twice though, as SDC and SDD:

$ lsblk -I 8
NAME                  MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sda                     8:0    0   4.4T  0 disk
├─sda1                  8:1    0   512M  0 part /boot/efi
└─sda2                  8:2    0   4.4T  0 part
  ├─ubuntu--vg-root   253:0    0   4.4T  0 lvm  /
  └─ubuntu--vg-swap_1 253:1    0   976M  0 lvm  [SWAP]
sdb                     8:16   0 223.5G  0 disk
sdc                     8:32   0 837.3G  0 disk
sdd                     8:48   0 837.3G  0 disk

The storage on SDC/SDD has not been formatted or anything yet.

How do I configure it so that the server knows SDC and SDD are redundant connections to the same RAID1 block of storage on the array? Does it have something to do with the way I configured it on the Powervault?

I'm trying to set up hostapd on linux machine as a network authenticator with 802.1x.

I've been mostly following this guide, with some adaptations since I'm using Ubuntu Jammy instead of RHEL, and using veth interfaces in the bridge instead of physical ones.

I created the hostapd.conf file as instructed with the content as they described - My bridge interface is br0 like in the sample, I changed the own_ip_addr to the IP on interface br0, and changed the nas_identifier, auth_server_addr, auth_server_shared_secret, acct_server_addr, and acct_server_shared_secret to match the config on my RADIUS server.

Everything else is the same as the example file, but for some reason hostapd wont start. /var/log/syslog says there is an error in the config file but doesn't really explain what the problem is:

Oct 25 13:47:13 blackfox systemd[1]: hostapd.service: Scheduled restart job, restart counter is at 320.
Oct 25 13:47:13 blackfox hostapd[347060]: 1 errors found in configuration file '/etc/hostapd/hostapd.conf'
Oct 25 13:47:13 blackfox hostapd[347060]: Failed to set up interface with /etc/hostapd/hostapd.conf
Oct 25 13:47:13 blackfox hostapd[347060]: Failed to initialize interface
Oct 25 13:47:13 blackfox systemd[1]: hostapd.service: Control process exited, code=exited, status=1/FAILURE
Oct 25 13:47:13 blackfox systemd[1]: hostapd.service: Failed with result 'exit-code'.
Oct 25 13:47:15 blackfox systemd[1]: hostapd.service: Scheduled restart job, restart counter is at 321.
Oct 25 13:47:15 blackfox hostapd[347062]: 1 errors found in configuration file '/etc/hostapd/hostapd.conf'
Oct 25 13:47:15 blackfox hostapd[347062]: Failed to set up interface with /etc/hostapd/hostapd.conf
Oct 25 13:47:15 blackfox hostapd[347062]: Failed to initialize interface
Oct 25 13:47:15 blackfox systemd[1]: hostapd.service: Control process exited, code=exited, status=1/FAILURE
Oct 25 13:47:15 blackfox systemd[1]: hostapd.service: Failed with result 'exit-code'.
Oct 25 13:47:17 blackfox systemd[1]: hostapd.service: Scheduled restart job, restart counter is at 322.
Oct 25 13:47:17 blackfox hostapd[347065]: 1 errors found in configuration file '/etc/hostapd/hostapd.conf'
Oct 25 13:47:17 blackfox hostapd[347065]: Failed to set up interface with /etc/hostapd/hostapd.conf
Oct 25 13:47:17 blackfox hostapd[347065]: Failed to initialize interface
Oct 25 13:47:17 blackfox systemd[1]: hostapd.service: Control process exited, code=exited, status=1/FAILURE
Oct 25 13:47:17 blackfox systemd[1]: hostapd.service: Failed with result 'exit-code'.

Does anyone have any idea what's going on?

This will probably be easier to explain with a diagram, so this is the basic setup:

There are 2 containers 10.0.0.1 & 10.0.0.2 running inside a host machine, and I've also created a linux bridge br0.

Each of the containers sees its own network interface as eth0, but the host machine sees it as vethxxxx. Looking at the picture in the basic setup, there is no connectivity between the containers.

What I can do easily is to add both veth interfaces into the bridge using brctl addif, and they will be able to communicate right away, but this is not exactly what I am looking to do.

What I want to do is to be able to have more granular control over the forwarding between the containers; to emulate a managed switch on br0 controlled by the host machine. If these were physical machines, I believe this could be done using nmcli with something like:

nmcli connection add type ethernet slave-type bridge con-name br0-port1 ifname <port name> master br0

and then connect the cables from the machines into the ports used in that command.

Is there a way to effectively achieve the same setup virtually (like in pic #3)?