bind: cannot assign requested address

[git-Charlie]

centos7 , docker cmd:

 docker run --rm  -v /root/caddy:/config caddy/caddy

print logs

2020/03/10 17:21:28.594	INFO	using provided configuration	{"config_file": "/etc/caddy/Caddyfile", "config_adapter": "caddyfile"}
run: loading initial config: loading new config: starting caddy administration endpoint: listen tcp 37.152.88.55:2019: bind: cannot assign requested address

• the 37.152.... is not my IP address,
• I am test 4 server,
  • CentOS Linux release 7.6.1810 (Core) / Docker version 18.09.0, build 4d60db4 OK
  • CentOS Linux release 7.7.1908 (Core) / Docker version 19.03.5, build 633a0ea
    Error x2
  • Winddows 10 Docker version 19.03.5, build 633a0ea OK

[git-Charlie]

I am use global options block -> admin off ,
the problem was covered up

[hairyhenderson]

@git-Charlie I'm not sure why this'd be happening. What is the contents of /root/caddy when you start? is it empty?

[hairyhenderson]

When I run the same command, with an empty config mount, I see:

$ docker run --rm  -v $(pwd)/config:/config caddy/caddy
2020/03/11 01:44:27.150	INFO	using provided configuration	{"config_file": "/etc/caddy/Caddyfile", "config_adapter": "caddyfile"}
2020/03/11 01:44:27.154	INFO	admin	admin endpoint started	{"address": "localhost:2019", "enforce_origin": false, "origins": ["localhost:2019"]}
2020/03/11 01:44:27.155	INFO	http	server is listening only on the HTTP port, so no automatic HTTPS will be applied to this server	{"server_name": "srv0", "http_port": 80}
2020/03/11 01:44:27.155	INFO	tls	cleaned up storage units
2020/03/11 01:44:27.156	INFO	autosaved config	{"file": "/config/caddy/autosave.json"}
2020/03/11 01:44:27.156	INFO	serving initial configuration

[mholt]

Somehow localhost is resolving to 37.152.88.55?

[git-Charlie]

When I run the same command, with an empty config mount, I see:

$ docker run --rm  -v $(pwd)/config:/config caddy/caddy
2020/03/11 01:44:27.150	INFO	using provided configuration	{"config_file": "/etc/caddy/Caddyfile", "config_adapter": "caddyfile"}
2020/03/11 01:44:27.154	INFO	admin	admin endpoint started	{"address": "localhost:2019", "enforce_origin": false, "origins": ["localhost:2019"]}
2020/03/11 01:44:27.155	INFO	http	server is listening only on the HTTP port, so no automatic HTTPS will be applied to this server	{"server_name": "srv0", "http_port": 80}
2020/03/11 01:44:27.155	INFO	tls	cleaned up storage units
2020/03/11 01:44:27.156	INFO	autosaved config	{"file": "/config/caddy/autosave.json"}
2020/03/11 01:44:27.156	INFO	serving initial configuration

same error

[git-Charlie]

Somehow localhost is resolving to 37.152.88.55?

I don't think so ,
this is check step:

docker run -itd  caddy/caddy /bin/sh
# display like xxxxxx Container id
docker attach xxxxx
# attach to container
ping localhost

PING localhost (127.0.0.1): 56 data bytes
64 bytes from 127.0.0.1: seq=0 ttl=64 time=0.087 ms
64 bytes from 127.0.0.1: seq=1 ttl=64 time=0.121 ms
64 bytes from 127.0.0.1: seq=2 ttl=64 time=0.105 ms
64 bytes from 127.0.0.1: seq=3 ttl=64 time=0.111 ms
64 bytes from 127.0.0.1: seq=4 ttl=64 time=0.172 ms
^C
--- localhost ping statistics ---
5 packets transmitted, 5 packets received, 0% packet loss
round-trip min/avg/max = 0.087/0.119/0.172 ms

[git-Charlie]

I'm sure only a specific VPS provider has this problem (2 recently purchased VPS in same DC area).
But according to my understanding, shouldn't docker avoid this problem?
And I use the SSH connect to Vps Ping localhost , and the result is also 127.0.0.1

[git-Charlie]

I have a new discovery

ping localhost.es
PING localhost.es (37.152.88.55) 56(84) bytes of data.
64 bytes from parkingsrv0.dondominio.com (37.152.88.55): icmp_seq=1 ttl=54 time=165 ms
64 bytes from parkingsrv0.dondominio.com (37.152.88.55): icmp_seq=2 ttl=54 time=165 ms
64 bytes from parkingsrv0.dondominio.com (37.152.88.55): icmp_seq=3 ttl=54 time=164 ms

The hostname my VPS is xxx.es and yyy.es

In vps vim /etc/resolv.conf
remove line of search es
the problem is solved

[mholt]

Aye, that would do it; a misconfigured machine. Thanks for posting the solution!

[fabianlaule]

@mholt I'm a little bit confused why caddy automatically searches for "localhost" on the search path found in /etc/resolv.conf (as example mysearchpath.example.com) and tries to resolve it (so it tries localhost.mysearchpath.example.com). I ran today in the same issue and have never seen this behaviour in other tools.

[mholt]

I'm not sure; you'll have to ask the Go std lib maintainers or dig into the standard library to find the answer. Let us know what you find!