I am running openvpn client in a namespace. I am starting it as:
ip netns exec vpn openvpn --fast-io --config /etc/openvpn/OpenVPN-Configs/Random-TCP.ovpn
It works fine for a long time but sometimes it ends up printing:
Apr 26 13:48:43 ubuntu openvpn[5182]: RESOLVE: Cannot resolve host address: XXXXXXX:XXXX (Temporary failure in name resolution)
I ran strace on the process and found out that it is reading the default /etc/resolv.conf file. (I can see it as the first line in file is "# This file is managed") and it seems to be using 127.0.0.1 for DNS resolving but it won't work inside namespace!
sendto(3, "<27>Apr 26 13:53:43 openvpn[5182"..., 137, MSG_NOSIGNAL, NULL, 0) = 137
openat(AT_FDCWD, "/etc/resolv.conf", O_RDONLY|O_CLOEXEC) = 4
fstat(4, {st_mode=S_IFREG|0644, st_size=719, ...}) = 0
read(4, "# This file is managed by man:sy"..., 4096) = 719
read(4, "", 4096) = 0
close(4) = 0
getpid() = 5182
stat("/etc/resolv.conf", {st_mode=S_IFREG|0644, st_size=719, ...}) = 0
openat(AT_FDCWD, "/etc/hosts", O_RDONLY|O_CLOEXEC) = 4
lseek(4, 0, SEEK_CUR) = 0
fstat(4, {st_mode=S_IFREG|0644, st_size=287, ...}) = 0
read(4, "127.0.0.1\tlocalhost.localdomain\t"..., 4096) = 287
lseek(4, 0, SEEK_CUR) = 287
read(4, "", 4096) = 0
close(4) = 0
Normally I have an /etc/netns/vpn/resolv.conf file (which does NOT have a line like "# This file...") which should be used by processes running inside the namespace.
When I check the process with `ip netns identify OPENVPN_PID` I see that OpenVPN process is still inside the namespace it started in.
resolv.conf is a link: /etc/resolv.conf -> ../run/systemd/resolve/stub-resolv.conf
When I execute `ip netns exec vpn cat /etc/resolv.conf` I receive the contents of /etc/netns/vpn/resolv.conf as it should be...
Furthermore, DNS resolution works fine for other programs which are inside the namespace. So how come OpenVPN opens the wrong resolv.conf? Is this a bug?
Thanks!
