The problem

I used inet:gethostbyname(Hoststr) in a docker environment with a couple containers for over a year without problems. Due to non recoverable read errors on the SSD which -- according to the provider -- is perfectly fine I was forced to reinstall from scratch with a CentOS image.
After restore I get a crash which boils down to

3> inet:gethostbyname("www").
{ok,{hostent,"www",
             ["www"],
             inet,4,
             [{10,0,1,205},{10,0,1,180}]}}

obviously because I get 2 IPs.
getaddr works fine:

4> inet:getaddr("www", inet).
{ok,{10,0,1,205}}

Question

I can replace gethostbyname with getaddr , no problem, but I would like to know why I get 2 IPs in the first place and how this misbehavior could creep in.
PHP does just fine:

id=$(docker ps -a  | grep "vx_www.1\." | grep -v "xited" | awk '{print $1}') && docker exec -it $id ash
php > echo gethostbyname('www');
10.0.1.205

Is it a docker problem?

The problem may lie on the docker side, as both addresses ping.
It gets even more interesting (from the host):

/ # ip a | grep -oE "\b([0-9]{1,3}\.){3}[0-9]{1,3}\b"
127.0.0.1
10.0.1.205
10.0.1.255
172.18.0.13
172.18.255.255
10.0.8.33
10.0.8.255
10.0.0.162
10.0.0.255
10.0.9.19
10.0.9.255

This should show addresses from within the docker system, if I understand correctly, and the latter address is not in the list. But it is somewhere:

# docker inspect sa3oizstflg3  | grep "10.0.1"
                    "Addr": "10.0.1.180/24"

What is a VirtualIP?

Actually I get this address with the ID of www as VirtualIP together with a bunch of others

"VirtualIPs": [
            {
                "NetworkID": "y3rf5yes97yjs1rfzpzf4aou8",
                "Addr": "10.0.0.148/24"
            },
            {
                "NetworkID": "swagio8bzavl2bf5u5bivmt13",
                "Addr": "10.0.1.180/24"
            },
            {
                "NetworkID": "tnmpad21shpvsps6fps5m4own",
                "Addr": "10.0.8.5/24"
            },

                {
                    "NetworkID": "mz9aogx7jxit8x2bflgpyh5lh",
                    "Addr": "10.0.9.2/24"
                }

The same container listens to 2 different IPs

Taking a different container with PHP on board, I get the second address given by inet:gethostbyname("www") for the same container, so both seem to be correct and usable:

# id=$(docker ps -a  | grep "vx_wsm.1\." | grep -v "xited" | awk '{print $1}') && docker exec -it $id ash
    / # php -a
    Interactive shell
    
    php > echo gethostbyname('www');
    10.0.1.180

Now I am confused. Anybody knows what is happening here?
inet:gethostbyname seems to be not wrong but more correct, then.

Erlang question

As an addendum: I am not that proficient in Erlang. In my code it reads:

get_ip_web(Web) ->                                          % e.g. www = > 100.0.1.226
    [case X of $, -> $.; _ -> X end || X <- lists:flatten(io_lib:format("~p",element(6, element(2, inet:gethostbyname(Web))))), X=/=${, X=/=$}].

How to rewrite this fine piece of code to pick one of the two addresses, but working also with only one result?
Well, this is mostly an academic question as I didn't understand this one-liner at all initially -- my comment was incomprehensible. This is no longer the case, but I still struggle with constructs easy to handle in other languages, especially if there is no routine for a long time.
For your information: I replaced the one-liner above with this much simpler one-liner:
inet:ntoa(element(2,inet:getaddr(Web, inet)))